Sample records for material failure model

  1. Experiments for calibration and validation of plasticity and failure material modeling: 304L stainless steel.

    SciTech Connect (OSTI)

    Lee, Kenneth L.; Korellis, John S.; McFadden, Sam X.

    2006-01-01T23:59:59.000Z

    Experimental data for material plasticity and failure model calibration and validation were obtained from 304L stainless steel. Model calibration data were taken from smooth tension, notched tension, and compression tests. Model validation data were provided from experiments using thin-walled tube specimens subjected to path dependent combinations of internal pressure, extension, and torsion.

  2. Modeling the deformation and failure behavior of FCC and HCP nanocrystalline materials

    E-Print Network [OSTI]

    Wei, Yujie, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    As foreseen by Richard Feynman in his famous talk titled There's Plenty of Room at the Bottom in 1959, scientists nowadays are miniaturizing structures in materials to achieve better performance as concerned in technical ...

  3. Multiscale modeling and simulation of deformation and failure mechanisms of hierarchical alpha-helical protein materials

    E-Print Network [OSTI]

    Bertaud, Jeremie

    2009-01-01T23:59:59.000Z

    Alpha-helical (AH) protein structures are critical building blocks of life, representing the key constituents of biological materials such as cells, hair, hoof and wool, where they assemble to form hierarchical structures. ...

  4. Correlation of electrical reactor cable failure with materials degradation

    SciTech Connect (OSTI)

    Stuetzer, O.M.

    1986-03-01T23:59:59.000Z

    Complete circuit failure (shortout) of electrical cables typically used in nuclear power plant containments is investigated. Failure modes are correlated with the mechanical deterioration of the elastomeric cable materials. It is found that for normal reactor operation, electrical cables are reliable and safe over very long periods. During high temperature excursions, however, cables pulled across corners under high stress may short out due to conductor creep. Severe cracking will occur in short times during high temperatures (>150/sup 0/C) and in times of the order of years at elevated temperatures (100/sup 0/C to 140/sup 0/C). A theoretical treatment of stress distribution responsible for creep and for cracking by J.E. Reaugh of Science Applications, Inc. is contained in the Appendix. 29 refs., 32 figs.

  5. Modeling of microstructural effects on electromigration failure

    SciTech Connect (OSTI)

    Ceric, H. [Christian Doppler Laboratory for Reliability Issues in Microelectronics at the Institute for Microelectronics, TU Wien (Austria); Orio, R. L. de; Zisser, W.; Selberherr, S. [Institute for Microelectronics, TU Wien, Gußhausstraße 27-29, A-1040 Wien (Austria)

    2014-06-19T23:59:59.000Z

    Current electromigration models used for simulation and analysis of interconnect reliability lack the appropriate description of metal microstructure and consequently have a very limited predictive capability. Therefore, the main objective of our work was obtaining more sophisticated electromigration tools. The problem is addressed through a combination of different levels of atomistic modeling and already available, continuum level macroscopic models. A novel method for an ab initio calculation of the effective valence for electromigration is presented and its application on the analysis of EM behavior is demonstrated. Additionally, a simple analytical model for the early electromigration lifetime is obtained. We have shown that its application provides a reasonable estimate for the early electromigration failures including the effect of microstructure. A simulation study is also applied on electromigration failure in tin solder bumps, where it contributed the understanding of the role of tin crystal anisotropy in the degradation mechanism of solder bumps.

  6. A simple approach to modeling ductile failure.

    SciTech Connect (OSTI)

    Wellman, Gerald William

    2012-06-01T23:59:59.000Z

    Sandia National Laboratories has the need to predict the behavior of structures after the occurrence of an initial failure. In some cases determining the extent of failure, beyond initiation, is required, while in a few cases the initial failure is a design feature used to tailor the subsequent load paths. In either case, the ability to numerically simulate the initiation and propagation of failures is a highly desired capability. This document describes one approach to the simulation of failure initiation and propagation.

  7. Modelling of dependence between critical failure and preventive maintenance

    E-Print Network [OSTI]

    Langseth, Helge

    Modelling of dependence between critical failure and preventive maintenance: The repair alert model, or a preventive maintenance (PM) action, where the latter will prevent the failure. It is reasonable to expect that the failure can be avoided by a possible preventive maintenance (PM) at some random time Z. If Z

  8. Statistical Modeling of Corrosion Failures in Natural Gas Transmission Pipelines

    E-Print Network [OSTI]

    Cobanoglu, Mustafa Murat

    2014-03-28T23:59:59.000Z

    and deterioration processes in pipeline networks. Therefore, pipeline operators need to rethink their corrosion prevention strategies. These results of corrosion failures are forcing the companies to develop accurate maintenance models based on failure frequency...

  9. Ris-R-1736 (EN) Cohesive laws for assessment of materials failure

    E-Print Network [OSTI]

    Risø-R-1736 (EN) Cohesive laws for assessment of materials failure: Theory, experimental methods-opening reaches the critical s decreased to zero, 0 n . The bridging zone is further crack extension, the fracture laws for assessment of materials failure: Theory, experimental methods and application #12;#12;Cohesive

  10. Large-Scale Atomistic Simulations of Material Failure

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Abraham, Farid [IBM Almaden Research; Duchaineau, Mark [LLNL; Wirth, Brian [LLNL; Heidelberg,; Seager, Mark [LLNL; De La Rubia, Diaz [LLNL

    These simulations from 2000 examine the supersonic propagation of cracks and the formation of complex junction structures in metals. Eight simulations concerning brittle fracture, ductile failure, and shockless compression are available.

  11. Reactor Materials Program process water piping indirect failure frequency

    SciTech Connect (OSTI)

    Daugherty, W.L.

    1989-10-30T23:59:59.000Z

    Following completion of the probabilistic analyses, the LOCA Definition Project has been subject to various external reviews, and as a result the need for several revisions has arisen. This report updates and summarizes the indirect failure frequency analysis for the process water piping. In this report, a conservatism of the earlier analysis is removed, supporting lower failure frequency estimates. The analysis results are also reinterpreted in light of subsequent review comments.

  12. Modelling of dependence between critical failure and preventive maintenance

    E-Print Network [OSTI]

    Langseth, Helge

    Modelling of dependence between critical failure and preventive maintenance: The repair alert model, or a preventive maintenance (PM) action, where the latter will prevent the failure. It is reasonable to expect be avoided by a possible preventive maintenance (PM) at some random time Z. If Z

  13. Modeling Stress Strain Relationships and Predicting Failure Probabilities For Graphite Core Components

    SciTech Connect (OSTI)

    Duffy, Stephen

    2013-09-09T23:59:59.000Z

    This project will implement inelastic constitutive models that will yield the requisite stress-strain information necessary for graphite component design. Accurate knowledge of stress states (both elastic and inelastic) is required to assess how close a nuclear core component is to failure. Strain states are needed to assess deformations in order to ascertain serviceability issues relating to failure, e.g., whether too much shrinkage has taken place for the core to function properly. Failure probabilities, as opposed to safety factors, are required in order to capture the bariability in failure strength in tensile regimes. The current stress state is used to predict the probability of failure. Stochastic failure models will be developed that can accommodate possible material anisotropy. This work will also model material damage (i.e., degradation of mechanical properties) due to radiation exposure. The team will design tools for components fabricated from nuclear graphite. These tools must readily interact with finite element software--in particular, COMSOL, the software algorithm currently being utilized by the Idaho National Laboratory. For the eleastic response of graphite, the team will adopt anisotropic stress-strain relationships available in COMSO. Data from the literature will be utilized to characterize the appropriate elastic material constants.

  14. Cascade Failure in a Phase Model of Power Grids

    E-Print Network [OSTI]

    Sakaguchi, Hidetsugu

    2012-01-01T23:59:59.000Z

    We propose a phase model to study cascade failure in power grids composed of generators and loads. If the power demand is below a critical value, the model system of power grids maintains the standard frequency by feedback control. On the other hand, if the power demand exceeds the critical value, an electric failure occurs via step out (loss of synchronization) or voltage collapse. The two failures are incorporated as two removal rules of generator nodes and load nodes. We perform direct numerical simulation of the phase model on a scale-free network and compare the results with a mean-field approximation.

  15. A simple microscopic model for the dynamics of adhesive failure

    E-Print Network [OSTI]

    Dominic Vella; L. Mahadevan

    2005-12-27T23:59:59.000Z

    We consider a microscopic model for the failure of soft adhesives in tension based on ideas of bond rupture under dynamic loading. Focusing on adhesive failure under loading at constant velocity, we demonstrate that bi-modal curves of stress against strain may occur due to effects of finite polymer chain or bond length and characterise the loading conditions under which such bi-modal behaviour is observed. The results of this analysis are in qualitative agreement with experiments performed on unconfined adhesives in which failure does not occur by cavitation.

  16. Dynamic Modeling of Cascading Failure in Power Systems

    E-Print Network [OSTI]

    Song, Jiajia; Ghanavati, Goodarz; Hines, Paul D H

    2014-01-01T23:59:59.000Z

    The modeling of cascading failure in power systems is difficult because of the many different mechanisms involved; no single model captures all of these mechanisms. Understanding the relative importance of these different mechanisms is an important step in choosing which mechanisms need to be modeled for particular types of cascading failure analysis. This work presents a dynamic simulation model of both power networks and protection systems, which can simulate a wider variety of cascading outage mechanisms, relative to existing quasi-steady state (QSS) models. The model allows one to test the impact of different load models and protections on cascading outage sizes. This paper describes each module of the developed dynamic model and demonstrates how different mechanisms interact. In order to test the model we simulated a batch of randomly selected $N-2$ contingencies for several different static load configurations, and found that the distribution of blackout sizes and event lengths from the proposed dynamic...

  17. Transport and Failure in Li-ion Batteries | Stanford Synchrotron...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    is well predicted by the macrohomogeneous model of Newman and co-workers, predicting degradation and failure remains a challenge. It may be that, like most materials, failure...

  18. Failure by fracture and fatigue in 'NANO' and 'BIO'materials

    SciTech Connect (OSTI)

    Ritchie, R.O.; Muhlstein, C.L.; Nalla, R.K.

    2003-12-19T23:59:59.000Z

    The behavior of nanostructured materials/small-volumestructures and biologi-cal/bio-implantable materials, so-called "nano"and "bio" materials, is currently much in vogue in materials science. Oneaspect of this field, which to date has received only limited attention,is their fracture and fatigue properties. In this paper, we examine twotopics in this area, namely the premature fatigue failure ofsilicon-based micron-scale structures for microelectromechanical systems(MEMS), and the fracture properties of mineralized tissue, specificallyhuman bone.

  19. Modeling Different Failure Mechanisms in Metals 

    E-Print Network [OSTI]

    Zhang, Liang

    2012-02-14T23:59:59.000Z

    . Keeler [1] and Goodwin [2] first introduced the concept of the forming limit diagram (FLD). The FLD plots the limiting major and minor strains that can be achieved along different stress or strain paths. It characterizes the sheet metal formability..., the quadratic yield criterions are still often employed to examine the validity of new models. 6 Keeler and Brazier [7] observed that, for steel sheets, the limiting major strain under plane strain conditions increases with increasing sheet thickness...

  20. Bayesian failure probability model sensitivity study. Final report

    SciTech Connect (OSTI)

    Not Available

    1986-05-30T23:59:59.000Z

    The Office of the Manager, National Communications System (OMNCS) has developed a system-level approach for estimating the effects of High-Altitude Electromagnetic Pulse (HEMP) on the connectivity of telecommunications networks. This approach incorporates a Bayesian statistical model which estimates the HEMP-induced failure probabilities of telecommunications switches and transmission facilities. The purpose of this analysis is to address the sensitivity of the Bayesian model. This is done by systematically varying two model input parameters--the number of observations, and the equipment failure rates. Throughout the study, a non-informative prior distribution is used. The sensitivity of the Bayesian model to the noninformative prior distribution is investigated from a theoretical mathematical perspective.

  1. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    SciTech Connect (OSTI)

    Fok, Alex

    2013-10-30T23:59:59.000Z

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  2. Critical Material Parameters for Modeling Devices Made from an Epoxy-Based Shape Memory Polymer 

    E-Print Network [OSTI]

    Erel, Veysel

    2014-06-17T23:59:59.000Z

    the material. The strain to failure was small, and insufficient for extracting hyperelastic parameters. Using narrower gage width specimens, or perhaps a new specimen design, would benefit modeling and analysis for this material....

  3. RECONFIGURING POWER SYSTEMS TO MINIMIZE CASCADING FAILURES: MODELS AND ALGORITHMS

    SciTech Connect (OSTI)

    Bienstock, Daniel

    2014-04-11T23:59:59.000Z

    the main goal of this project was to develop new scientific tools, based on optimization techniques, with the purpose of controlling and modeling cascading failures of electrical power transmission systems. We have developed a high-quality tool for simulating cascading failures. The problem of how to control a cascade was addressed, with the aim of stopping the cascade with a minimum of load lost. Yet another aspect of cascade is the investigation of which events would trigger a cascade, or more appropriately the computation of the most harmful initiating event given some constraint on the severity of the event. One common feature of the cascade models described (indeed, of several of the cascade models found in the literature) is that we study thermally-induced line tripping. We have produced a study that accounts for exogenous randomness (e.g. wind and ambient temperature) that could affect the thermal behavior of a line, with a focus on controlling the power flow of the line while maintaining safe probability of line overload. This was done by means of a rigorous analysis of a stochastic version of the heat equation. we incorporated a model of randomness in the behavior of wind power output; again modeling an OPF-like problem that uses chance-constraints to maintain low probability of line overloads; this work has been continued so as to account for generator dynamics as well.

  4. ISSUES ASSOCIATED WITH PROBABILISTIC FAILURE MODELING OF DIGITAL SYSTEMS

    SciTech Connect (OSTI)

    CHU,T.L.; MARTINEZ-GURIDI,G.; LEHNER,J.; OVERLAND,D.

    2004-09-19T23:59:59.000Z

    The current U.S. Nuclear Regulatory Commission (NRC) licensing process of instrumentation and control (I&C) systems is based on deterministic requirements, e.g., single failure criteria, and defense in depth and diversity. Probabilistic considerations can be used as supplements to the deterministic process. The National Research Council has recommended development of methods for estimating failure probabilities of digital systems, including commercial off-the-shelf (COTS) equipment, for use in probabilistic risk assessment (PRA). NRC staff has developed informal qualitative and quantitative requirements for PRA modeling of digital systems. Brookhaven National Laboratory (BNL) has performed a review of the-state-of-the-art of the methods and tools that can potentially be used to model digital systems. The objectives of this paper are to summarize the review, discuss the issues associated with probabilistic modeling of digital systems, and identify potential areas of research that would enhance the state of the art toward a satisfactory modeling method that could be integrated with a typical probabilistic risk assessment.

  5. Dynamic model failure tests of dam structures Dalian University of Technology, Dalian 116024, China

    E-Print Network [OSTI]

    Spencer Jr., B.F.

    Dynamic model failure tests of dam structures Gao Lin Dalian University of Technology, Dalian failure tests of a number of concrete gravity dams, concrete arch dams and embankment dams have been index for the safety assessment of concrete dams and is predicted through dynamic model failure tests

  6. Critical points and transitions in an electric power transmission model for cascading failure blackouts

    E-Print Network [OSTI]

    Dobson, Ian

    Critical points and transitions in an electric power transmission model for cascading failure September 2002 Cascading failures in large-scale electric power transmission systems are an important cause, we examine cascading failure in a simplified transmission system model as load power demand

  7. Atomistc Models of LMRNMC Materials

    Broader source: Energy.gov (indexed) [DOE]

    Atomistic models of LMRNMC Materials Project ID ES: 193 Hakim Iddir Voltage Fade Team Annual Merit Review Washington DC, June 16-20, 2014 This presentation does not contain any...

  8. 318 IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY, VOL. 14, NO. 1, MARCH 2014 Thermomechanical Failure Analysis of

    E-Print Network [OSTI]

    Huang, Rui

    Thermomechanical Failure Analysis of Through-Silicon Via Interface Using a Shear-Lag Model With Cohesive Zone Suk for dam- age initiation and fracture initiation, respectively. It is found that via extrusion]­[17] as shown in Fig. 1. The via extrusion can cause interfacial failure of a TSV and/or cracking in Si near

  9. A coupled biventricular finite element and lumped-parameter circulatory system model of heart failure

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    Circulatory System Model of Heart Failure Jonathan F. Wenk,contracting regions of the heart. These single ventricledilation and help remodel the heart towards a normal state.

  10. Log-periodic behavior of a hierarchical failure model with ...

    E-Print Network [OSTI]

    earthquakes are accepted to be a type example of self— organization. ' We ?rst ..... the expected frictional heating on faults is not observed. [35]. The failure ...

  11. In-Vessel Coil Material Failure Rate Estimates for ITER Design Use

    SciTech Connect (OSTI)

    L. C. Cadwallader

    2013-01-01T23:59:59.000Z

    The ITER international project design teams are working to produce an engineering design for construction of this large tokamak fusion experiment. One of the design issues is ensuring proper control of the fusion plasma. In-vessel magnet coils may be needed for plasma control, especially the control of edge localized modes (ELMs) and plasma vertical stabilization (VS). These coils will be lifetime components that reside inside the ITER vacuum vessel behind the blanket modules. As such, their reliability is an important design issue since access will be time consuming if any type of repair were necessary. The following chapters give the research results and estimates of failure rates for the coil conductor and jacket materials to be used for the in-vessel coils. Copper and CuCrZr conductors, and stainless steel and Inconel jackets are examined.

  12. Modeling Stochastic Correlated Failures and their Effects on Network Reliability

    E-Print Network [OSTI]

    Hayat, Majeed M.

    --The physical infrastructure of communication net- works is vulnerable to spatially correlated failures arising geographically. In general, physical infrastructure of communication networks is vulnerable to failures-Naeini, Jorge E. Pezoa, Ghady Azar, Nasir Ghani, and Majeed M. Hayat Department of Electrical and Computer

  13. A robust Bayesian approach to modeling epistemic uncertainty in common-cause failure models

    SciTech Connect (OSTI)

    Matthias C. M. Troffaes; Gero Walter; Dana Kelly

    2014-05-01T23:59:59.000Z

    In a standard Bayesian approach to the alpha-factor model for common-cause failure, a precise Dirichlet prior distribution models epistemic uncertainty in the alpha-factors. This Dirichlet prior is then updated with observed data to obtain a posterior distribution, which forms the basis for further inferences. In this paper, we adapt the imprecise Dirichlet model of Walley to represent epistemic uncertainty in the alpha-factors. In this approach, epistemic uncertainty is expressed more cautiously via lower and upper expectations for each alpha-factor, along with a learning parameter which determines how quickly the model learns from observed data. For this application, we focus on elicitation of the learning parameter, and find that values in the range of 1 to 10 seem reasonable. The approach is compared with Kelly and Atwood's minimally informative Dirichlet prior for the alpha-factor model, which incorporated precise mean values for the alpha-factors, but which was otherwise quite diffuse. Next, we explore the use of a set of Gamma priors to model epistemic uncertainty in the marginal failure rate, expressed via a lower and upper expectation for this rate, again along with a learning parameter. As zero counts are generally less of an issue here, we find that the choice of this learning parameter is less crucial. Finally, we demonstrate how both epistemic uncertainty models can be combined to arrive at lower and upper expectations for all common-cause failure rates. Thereby, we effectively provide a full sensitivity analysis of common-cause failure rates, properly reflecting epistemic uncertainty of the analyst on all levels of the common-cause failure model.

  14. Statistical Modeling of Corrosion Failures in Natural Gas Transmission Pipelines 

    E-Print Network [OSTI]

    Cobanoglu, Mustafa Murat

    2014-03-28T23:59:59.000Z

    Natural gas pipelines are a critical component of the U.S. energy infrastructure. The safety of these pipelines plays a key role for the gas industry. Therefore, the understanding of failure characteristics and their consequences are very important...

  15. Material models of dark energy

    E-Print Network [OSTI]

    Jonathan A. Pearson

    2014-09-16T23:59:59.000Z

    We review and develop a new class of "dark energy" models, in which the relativistic theory of solids is used to construct material models of dark energy. These are models which include the effects of a continuous medium with well defined physical properties at the level of linearized perturbations. The formalism is constructed for a medium with arbitrary symmetry, and then specialised to isotropic media (which will be the case of interest for the majority of cosmological applications). We develop the theory of relativistic isotropic viscoelastic media whilst keeping in mind that we ultimately want to observationally constrain the allowed properties of the material model. We do this by obtaining the viscoelastic equations of state for perturbations (the entropy and anisotropic stress), as well as identifying the consistent corner of the theory which has constant equation of state parameter $\\dot{w}=0$. We also connect to the non-relativistic theory of solids, by identifying the two quadratic invariants that are needed to construct the energy-momentum tensor, namely the Rayleigh dissipation function and Lagrangian for perturbations. Finally, we develop the notion that the viscoelastic behavior of the medium can be thought of as a non-minimally coupled massive gravity theory. This also provides a tool-kit for constructing consistent generalizations of coupled dark energy theories.

  16. HYPERELASTIC MODELS FOR GRANULAR MATERIALS

    SciTech Connect (OSTI)

    Humrickhouse, Paul W; Corradini, Michael L

    2009-01-29T23:59:59.000Z

    A continuum framework for modeling of dust mobilization and transport, and the behavior of granular systems in general, has been reviewed, developed and evaluated for reactor design applications. The large quantities of micron-sized particles expected in the international fusion reactor design, ITER, will accumulate into piles and layers on surfaces, which are large relative to the individual particle size; thus, particle-particle, rather than particle-surface, interactions will determine the behavior of the material in bulk, and a continuum approach is necessary and justified in treating the phenomena of interest; e.g., particle resuspension and transport. The various constitutive relations that characterize these solid particle interactions in dense granular flows have been discussed previously, but prior to mobilization their behavior is not even fluid. Even in the absence of adhesive forces between particles, dust or sand piles can exist in static equilibrium under gravity and other forces, e.g., fluid shear. Their behavior is understood to be elastic, though not linear. The recent “granular elasticity” theory proposes a non-linear elastic model based on “Hertz contacts” between particles; the theory identifies the Coulomb yield condition as a requirement for thermodynamic stability, and has successfully reproduced experimental results for stress distributions in sand piles. The granular elasticity theory is developed and implemented in a stand- alone model and then implemented as part of a finite element model, ABAQUS, to determine the stress distributions in dust piles subjected to shear by a fluid flow. We identify yield with the onset of mobilization, and establish, for a given dust pile and flow geometry, the threshold pressure (force) conditions on the surface due to flow required to initiate it. While the granular elasticity theory applies strictly to cohesionless granular materials, attractive forces are clearly important in the interaction of micron-sized particles; extension of the theory to account for these effects is also considered. A set of continuum models are proposed for use in the future dust transport modeling.

  17. Waves and propagation failure in discrete space models with nonlinear coupling and

    E-Print Network [OSTI]

    Waves and propagation failure in discrete space models with nonlinear coupling and feedback Markus by the linearisation ahead of the wave front. Wave propagation (and failure) is studied when the homogeneous dynamics are bistable. Simulations show that waves may propagate in either direction, or may be pinned. A Lyapunov

  18. The Impact of the Topology on Cascading Failures in a Power Grid Model

    E-Print Network [OSTI]

    Van Mieghem, Piet

    allocation according to Kirchoff Laws. Experimental verification on synthetic power systems showsThe Impact of the Topology on Cascading Failures in a Power Grid Model Yakup Koça,1 Martijn on the IEEE 118 bus power system to improve its robustness against cascading failures. 1. Introduction

  19. A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids

    E-Print Network [OSTI]

    Hayat, Majeed M.

    systems. The control system of a reliable power grid requires (1) a good understanding of the current in the control/communication systems) factors can affect cascading failures in power grids. These factors can1 A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids Mahshid

  20. Common-Cause Failure Treatment in Event Assessment: Basis for a Proposed New Model

    SciTech Connect (OSTI)

    Dana Kelly; Song-Hua Shen; Gary DeMoss; Kevin Coyne; Don Marksberry

    2010-06-01T23:59:59.000Z

    Event assessment is an application of probabilistic risk assessment in which observed equipment failures and outages are mapped into the risk model to obtain a numerical estimate of the event’s risk significance. In this paper, we focus on retrospective assessments to estimate the risk significance of degraded conditions such as equipment failure accompanied by a deficiency in a process such as maintenance practices. In modeling such events, the basic events in the risk model that are associated with observed failures and other off-normal situations are typically configured to be failed, while those associated with observed successes and unchallenged components are assumed capable of failing, typically with their baseline probabilities. This is referred to as the failure memory approach to event assessment. The conditioning of common-cause failure probabilities for the common cause component group associated with the observed component failure is particularly important, as it is insufficient to simply leave these probabilities at their baseline values, and doing so may result in a significant underestimate of risk significance for the event. Past work in this area has focused on the mathematics of the adjustment. In this paper, we review the Basic Parameter Model for common-cause failure, which underlies most current risk modelling, discuss the limitations of this model with respect to event assessment, and introduce a proposed new framework for common-cause failure, which uses a Bayesian network to model underlying causes of failure, and which has the potential to overcome the limitations of the Basic Parameter Model with respect to event assessment.

  1. A MAINTENANCE MODEL FOR COMPONENTS EXPOSED TO SEVERAL FAILURE MECHANISMS

    E-Print Network [OSTI]

    Langseth, Helge

    . The preventive maintenance (PM) is performed periodically with some fixed period , but PM can also be performed describe the "goodness" of the maintenance crew; their ability to prevent failures by performing thorough is assumed to undergo preventive maintenance (PM), usually at fixed time periods > 0. In addition

  2. ARRA: Reconfiguring Power Systems to Minimize Cascading Failures - Models and Algorithms

    SciTech Connect (OSTI)

    Dobson, Ian [Iowa State University] [Iowa State University; Hiskens, Ian [Unversity of Michigan] [Unversity of Michigan; Linderoth, Jeffrey [University of Wisconsin-Madison] [University of Wisconsin-Madison; Wright, Stephen [University of Wisconsin-Madison] [University of Wisconsin-Madison

    2013-12-16T23:59:59.000Z

    Building on models of electrical power systems, and on powerful mathematical techniques including optimization, model predictive control, and simluation, this project investigated important issues related to the stable operation of power grids. A topic of particular focus was cascading failures of the power grid: simulation, quantification, mitigation, and control. We also analyzed the vulnerability of networks to component failures, and the design of networks that are responsive to and robust to such failures. Numerous other related topics were investigated, including energy hubs and cascading stall of induction machines

  3. An Attempt to Calibrate and Validate a Simple Ductile Failure Model Against Axial-Torsion Experiments on Al 6061-T651.

    SciTech Connect (OSTI)

    Reedlunn, Benjamin; Lu, Wei-Yang [Sandia National Laboratories, Livermore, CA

    2015-01-01T23:59:59.000Z

    This report details a work in progress. We have attempted to calibrate and validate a Von Mises plasticity model with the Johnson-Cook failure criterion ( Johnson & Cook , 1985 ) against a set of experiments on various specimens of Al 6061-T651. As will be shown, the effort was not successful, despite considerable attention to detail. When the model was com- pared against axial-torsion experiments on tubes, it over predicted failure by 3 x in tension, and never predicted failure in torsion, even when the tube was twisted by 4 x further than the experiment. While this result is unfortunate, it is not surprising. Ductile failure is not well understood. In future work, we will explore whether more sophisticated material mod- els of plasticity and failure will improve the predictions. Selecting the appropriate advanced material model and interpreting the results of said model are not trivial exercises, so it is worthwhile to fully investigate the behavior of a simple plasticity model before moving on to an anisotropic yield surface or a similarly complicated model.

  4. A Predictive Model of Fragmentation using Adaptive Mesh Refinement and a Hierarchical Material Model

    SciTech Connect (OSTI)

    Koniges, A E; Masters, N D; Fisher, A C; Anderson, R W; Eder, D C; Benson, D; Kaiser, T B; Gunney, B T; Wang, P; Maddox, B R; Hansen, J F; Kalantar, D H; Dixit, P; Jarmakani, H; Meyers, M A

    2009-03-03T23:59:59.000Z

    Fragmentation is a fundamental material process that naturally spans spatial scales from microscopic to macroscopic. We developed a mathematical framework using an innovative combination of hierarchical material modeling (HMM) and adaptive mesh refinement (AMR) to connect the continuum to microstructural regimes. This framework has been implemented in a new multi-physics, multi-scale, 3D simulation code, NIF ALE-AMR. New multi-material volume fraction and interface reconstruction algorithms were developed for this new code, which is leading the world effort in hydrodynamic simulations that combine AMR with ALE (Arbitrary Lagrangian-Eulerian) techniques. The interface reconstruction algorithm is also used to produce fragments following material failure. In general, the material strength and failure models have history vector components that must be advected along with other properties of the mesh during remap stage of the ALE hydrodynamics. The fragmentation models are validated against an electromagnetically driven expanding ring experiment and dedicated laser-based fragmentation experiments conducted at the Jupiter Laser Facility. As part of the exit plan, the NIF ALE-AMR code was applied to a number of fragmentation problems of interest to the National Ignition Facility (NIF). One example shows the added benefit of multi-material ALE-AMR that relaxes the requirement that material boundaries must be along mesh boundaries.

  5. Material model library for explicit numerical codes

    SciTech Connect (OSTI)

    Hofmann, R.; Dial, B.W.

    1982-08-01T23:59:59.000Z

    A material model logic structure has been developed which is useful for most explicit finite-difference and explicit finite-element Lagrange computer codes. This structure has been implemented and tested in the STEALTH codes to provide an example for researchers who wish to implement it in generically similar codes. In parallel with these models, material parameter libraries have been created for the implemented models for materials which are often needed in DoD applications.

  6. Failure Mode Analysis of a Proposed Manipulator-based Hazardous Material Retrieval System

    E-Print Network [OSTI]

    Cavallaro, Joseph R.

    for manipulators involved in hazardous waste management operations, where failure could be both expensive (supplied by Westinghouse Hanford Company), a design report on the Hose Management Arm (HMA),1 modes of a robot manipulator-based system for tank waste retrieval. The advantages and limitations

  7. Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling

    SciTech Connect (OSTI)

    Du, Qiang

    2014-11-12T23:59:59.000Z

    The rational design of materials, the development of accurate and efficient material simulation algorithms, and the determination of the response of materials to environments and loads occurring in practice all require an understanding of mechanics at disparate spatial and temporal scales. The project addresses mathematical and numerical analyses for material problems for which relevant scales range from those usually treated by molecular dynamics all the way up to those most often treated by classical elasticity. The prevalent approach towards developing a multiscale material model couples two or more well known models, e.g., molecular dynamics and classical elasticity, each of which is useful at a different scale, creating a multiscale multi-model. However, the challenges behind such a coupling are formidable and largely arise because the atomistic and continuum models employ nonlocal and local models of force, respectively. The project focuses on a multiscale analysis of the peridynamics materials model. Peridynamics can be used as a transition between molecular dynamics and classical elasticity so that the difficulties encountered when directly coupling those two models are mitigated. In addition, in some situations, peridynamics can be used all by itself as a material model that accurately and efficiently captures the behavior of materials over a wide range of spatial and temporal scales. Peridynamics is well suited to these purposes because it employs a nonlocal model of force, analogous to that of molecular dynamics; furthermore, at sufficiently large length scales and assuming smooth deformation, peridynamics can be approximated by classical elasticity. The project will extend the emerging mathematical and numerical analysis of peridynamics. One goal is to develop a peridynamics-enabled multiscale multi-model that potentially provides a new and more extensive mathematical basis for coupling classical elasticity and molecular dynamics, thus enabling next generation atomistic-to-continuum multiscale simulations. In addition, a rigorous study of nite element discretizations of peridynamics will be considered. Using the fact that peridynamics is spatially derivative free, we will also characterize the space of admissible peridynamic solutions and carry out systematic analyses of the models, in particular rigorously showing how peridynamics encompasses fracture and other failure phenomena. Additional aspects of the project include the mathematical and numerical analysis of peridynamics applied to stochastic peridynamics models. In summary, the project will make feasible mathematically consistent multiscale models for the analysis and design of advanced materials.

  8. Analysis and dynamic modeling of a moraine failure and glacier lake outburst flood at Ventisquero Negro, Patagonian Andes (Argentina)

    E-Print Network [OSTI]

    Stoffel, Markus

    Outburst hydrograph s u m m a r y Although moraine dams are inherently prone to failure because and the application of a dynamic dam break model. Results indicate that the moraine failure was caused most probably erosion and finally to dam failure. The lake volume of ca. 10 Â 106 m3 was released in ca. 3 h, producing

  9. ATOMISTIC MODELING OF ELECTRODE MATERIALS

    Broader source: Energy.gov (indexed) [DOE]

    life and rate * High cost of electrode materials * Project lead: Venkat Srinivasan (LBNL) * Marca Doeff (LBNL): Al-substituted layered Li-TM-O 2 * Phil Ross (LBNL) and Gerbrand...

  10. Atomistic Modeling of Electrode Materials

    Broader source: Energy.gov (indexed) [DOE]

    and rate * High cost of electrode materials * Project lead: John Newman * Marca Doeff (LBNL) on layered Li-TM-O 2 for effects of Al substitution * Phil Ross (LBNL) on nano-LiFePO...

  11. LLNL-TR-632239 Modeling Thermally Induced Failure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tural models used to represent thermal spallation at the grain scale. The explicit grain-scale model is used to investigate the grain spallation for a va- riety of different...

  12. Micromechanical Damage Models for Continuous Fiber Reinforced Composite Materials

    E-Print Network [OSTI]

    Wu, Yi

    2013-01-01T23:59:59.000Z

    2008). Micromechanical modeling of damage and fracture ofmatrix viscoplasticity and evolving damage, Journal of theW.A. (1998). Stochastic damage evolution and failure in

  13. Waste Form Degradation Model Integration for Engineered Materials...

    Office of Environmental Management (EM)

    Waste Form Degradation Model Integration for Engineered Materials Performance Waste Form Degradation Model Integration for Engineered Materials Performance The collaborative...

  14. A Bayesian Bivariate Failure Time Regression Model by Paul Damien

    E-Print Network [OSTI]

    West, Mike

    . In engineering studies, reliability is defined as the probability that the system has not failed at time t . The reliability of a system using the model in (1) is given by R(t) = P (T 1 ? t; T 2 ? t) = exp(\\Gammaâ??t)[1 using Markov Chain Monte Carlo methods. Keywords: Gumbel Distribution, Gibbs Sampling, Correlation

  15. MODELISATION DU TAUX DE DEFAILLANCE EN MECANIQUE MECHANICAL FAILURE RATE MODEL

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . Summary Electromechanical and mechanical equipment reliability databases do not seem as widespread of the reliability of (electro-)mechanical equipment and the dispersion of failure rates for apparently similar. This statement explains itself by the nature of its which do not propose prediction reliability model but present

  16. Deformation rate effects on failure modes of open-cell Al foams and textile cellular materials

    E-Print Network [OSTI]

    Barthelat, Francois

    September 2005 Abstract The compressive behavior of open-cell aluminum alloy foam and stainless steel woven: Metallic cellular materials; Dynamic compression; Aluminum foams; Woven textile lattice 0020-7683/$ - see are of attracting interest for a variety of automotive, locomotive, marine, and aerospace applications (Gibson

  17. Scientists use world's fastest computer to model materials under...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Materials under extreme conditions Scientists use world's fastest computer to model materials under extreme conditions Materials scientists are for the first time attempting to...

  18. Extended Rayleigh model of bubble evolution with material strength compared to detailed dynamic simulations

    SciTech Connect (OSTI)

    Glinsky, M.E.; Amendt, P.A.; Bailey, D.S.; London, R.A.; Rubenchik, A.M. [Lawrence Livermore National Lab., CA (United States); Strauss, M. [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1997-03-04T23:59:59.000Z

    The validity of an extended Rayleigh model for laser generated bubbles in soft tissue is examined. This model includes surface tension, viscosity, a realistic water equation of state, material strength and failure, stress wave emission, and linear growth of interface instabilities. It is compared to dynamic simulations using LATIS, which include stress wave propagation, water equation of state, material strength and failure, and viscosity. The model and the simulations are compared using 1-D spherical geometry with bubble in center and a 2-D cylindrical geometry of a laser fiber in water with a bubble formed at the end of the fiber. The model executes over 300x faster on computer than the dynamic simulations.

  19. Failure of the Shockley-Haynes Mobility Experiment with organic semiconducting materials

    E-Print Network [OSTI]

    Boehme, Hollis Clyde

    1961-01-01T23:59:59.000Z

    requirements for the degree of NASTER OF SCIENCE August 1961 Major Subjectt Physics PAILUHE OP THE SHOCKLEY-HAYNES MO31LITY EXPERIMENT I/ITH ORGANIC SEMICONDUCTING MATERIALS s nl A rA X W R i 0 0 g A Thesis HOLLIS CLYDE BOEHME Approved... s . ~pa '"e iii List of Tables I. Intro4uotion II. Sample Prepare. tion III. Nobility FEeasurement Attempts IV. Contacts. V. Discussion of Results BlblioEErap?y 16 52 LIST Oy r IQURr', S ~pa e l. Experimental arrangement of Shockley and Haynes...

  20. Scaling of structural failure

    SciTech Connect (OSTI)

    Bazant, Z.P. [Northwestern Univ., Evanston, IL (United States); Chen, Er-Ping [Sandia National Lab., Albuquerque, NM (United States)

    1997-01-01T23:59:59.000Z

    This article attempts to review the progress achieved in the understanding of scaling and size effect in the failure of structures. Particular emphasis is placed on quasibrittle materials for which the size effect is complicated. Attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, nonlocal finite element models and discrete element models. Extensions to compression failure and to the rate-dependent material behavior are also outlined. The damage constitutive law needed for describing a microcracked material in the fracture process zone is discussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber composites, rocks and ceramics are presented.

  1. Theory and Modeling of Weakly Bound/Physisorbed Materials for...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Theory and Modeling of Weakly BoundPhysisorbed Materials for Hydrogen Storage Theory and Modeling of Weakly BoundPhysisorbed Materials for Hydrogen Storage Presentation on the...

  2. DYNAMIC FAILURE OF METALLIC CELLULAR MATERIALS S. LEE and H.D. ESPINOSA

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    interest in the protection design in automotive, locomotive, naval structures, and aerospace. Metallic not observe any rate dependency for the crashing stress of aluminum foams. These discrepancies from different within the specimen at very high strain rates. A model for shock waves in closed cell aluminum foams

  3. Cascading dynamics and mitigation assessment in power system disturbances via a hidden failure model

    E-Print Network [OSTI]

    Dobson, Ian

    system reliability; Protective relaying hidden failures; Blackout mitigation 1. Introduction, which is often referred to as a hidden failure [7]. Hidden failures in protective relays disturbances involved relaying systems, not necessarily as the initiating event, but contributing

  4. NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION

    SciTech Connect (OSTI)

    Koeppel, Brian J.; Liu, Wenning N.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-11-01T23:59:59.000Z

    Numerical modeling was used to simulate the constrained sintering process of the cathode contact layer during assembly of solid oxide fuel cells (SOFCs). A finite element model based on the continuum theory for sintering of porous bodies was developed and used to investigate candidate low-temperature cathode contact materials. Constitutive parameters for various contact materials under investigation were estimated from dilatometry screening tests, and the influence of processing time, processing temperature, initial grain size, and applied compressive stress on the free sintering response was predicted for selected candidate materials. The densification behavior and generated stresses within a 5-cell planar SOFC stack during sintering, high temperature operation, and room temperature shutdown were predicted. Insufficient constrained densification was observed in the stack at the proposed heat treatment, but beneficial effects of reduced grain size, compressive stack preload, and reduced thermal expansion coefficient on the contact layer densification and stresses were observed.

  5. Modelling Inter-Industry Material Flows

    E-Print Network [OSTI]

    ............................................................................................ 4 3.1.2. Life-cycle Analysis. The development of energy-materials-economic models arose out of the need for tools to aid the development, capable of representing complex systems and interactions in a comprehensive and concise way. However

  6. Failure of semiclassical models to describe resistivity of nanometric, polycrystalline tungsten films

    SciTech Connect (OSTI)

    Choi, Dooho [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Korea Railroad Research Institute, 360-1 Woulam, Uiwang, Kyunggi 437-757 (Korea, Republic of); Liu, Xuan [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Schelling, Patrick K. [Advanced Materials Processing and Analysis Center and Department of Physics, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States); Coffey, Kevin R. [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States); Barmak, Katayun [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Department of Applied Physics and Applied Mathematics, Columbia University, 500 West 120th Street, New York, New York 10027 (United States)

    2014-03-14T23:59:59.000Z

    The impact of electron scattering at surfaces and grain boundaries in nanometric polycrystalline tungsten (W) films was studied. A series of polycrystalline W films ranging in thickness from 10 to 310?nm and lateral grain size from 74 to 133?nm were prepared on thermally oxidized Si. The Fuchs-Sondheimer surface-scattering model and Mayadas-Shatzkes grain-boundary scattering model were employed for quantitative analyses. Predictions from the theoretical models were found to deviate systematically from the experimental data. Possible reasons for the failure of the theoretical models to describe the experimental data are explored. Finally, a discussion of the crucial features lacking from existing models is presented, along with possible avenues for improving the models to result in better agreement with experimental data.

  7. Comparison of Hyperelastic Models for Granular Materials

    SciTech Connect (OSTI)

    Paul W. Humrickhouse; J. Phil Sharpe; Michael L. Corradini

    2010-01-01T23:59:59.000Z

    Three recently proposed hyperelastic models for granular materials are compared with experiment data. Though all three are formulated to give elastic moduli that are power law functions of the mean stress, they have rather different dependencies on individual stresses, and generally differ from well established experimental forms. Predicted static stress distributions are in qualitative agreement with experiments, but do not differ greatly from isotropic linear elasticity, and similarly fail to account for variability in experiment data that presumably occurs due to a preparation dependence of granular materials.

  8. A Mid-Layer Model for Human Reliability Analysis: Understanding the Cognitive Causes of Human Failure Events

    SciTech Connect (OSTI)

    Stacey M. L. Hendrickson; April M. Whaley; Ronald L. Boring; James Y. H. Chang; Song-Hua Shen; Ali Mosleh; Johanna H. Oxstrand; John A. Forester; Dana L. Kelly; Erasmia L. Lois

    2010-06-01T23:59:59.000Z

    The Office of Nuclear Regulatory Research (RES) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method’s middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identified human failure events, analysts identify potential failure mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.

  9. A mid-layer model for human reliability analysis : understanding the cognitive causes of human failure events.

    SciTech Connect (OSTI)

    Shen, Song-Hua (US Nuclear Regulatory Commission, Washington, DC); Chang, James Y. H. (US Nuclear Regulatory Commission, Washington, DC); Boring,Ronald L. (Idaho National Laboratory, Idaho Falls, ID); Whaley, April M. (Idaho National Laboratory, Idaho Falls, ID); Lois, Erasmia (US Nuclear Regulatory Commission, Washington, DC); Hendrickson, Stacey M. Langfitt; Oxstrand, Johanna H. (Vattenfall Ringhals AB, Varobacka, Sweden); Forester, John Alan; Kelly, Dana L. (Idaho National Laboratory, Idaho Falls, ID); Mosleh, Ali (University of Maryland, College Park, MD)

    2010-03-01T23:59:59.000Z

    The Office of Nuclear Regulatory Research (RES) at the US Nuclear Regulatory Commission (USNRC) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method's middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identified human failure events, analysts identify potential failure mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.

  10. Failure probability of axially cracked steam generator tubes; A probabilistic fracture mechanics model

    SciTech Connect (OSTI)

    Mavko, B.; Cizelj, L. (Jozef Stefan Inst., Reactor Engineering Div., P.O. Box 100, 61111 Ljubljana, Slovenia (YU))

    1992-05-01T23:59:59.000Z

    In this paper a model for estimating the failure probability of axially cracked steam generator tubes is proposed. The model compares observed crack length distribution with critical crack length distribution by means of probabilistic fracture mechanics. The observed crack length is influenced by measured data, measurement reliability, sizing accuracy, and predicted crack growth rate. The critical crack length is defined by a deterministic mechanical model. All cracks are conservatively assumed to extend through the tube wall. The effect of the plugging limit is studied along with the number of cracked tubes to perform risk-based lifetime optimization of steam generators. A numerical example presented considers hypothetical accidental operating conditions during a feedwater line break.

  11. Materials Theory, Modeling and Simulation | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Materials Characterization Materials Theory and Simulation Quantum Monte Carlo Density Functional Theory Monte Carlo Ab Initio Molecular Dynamics Chemical and Materials Theory...

  12. Patient-specific modeling of cardiac electromechanics in dyssynchronous heart failure

    E-Print Network [OSTI]

    Shin, Jun Seob

    2009-01-01T23:59:59.000Z

    1.3 Congestive Heart1.1: Longitudinal cross-section of the heart . . . . . . .Classification of heart failure . . . . . . . . . . . .

  13. The equal load-sharing model of cascade failures in power grids

    E-Print Network [OSTI]

    Scala, Antonio

    2015-01-01T23:59:59.000Z

    Electric power-systems are one of the most important critical infrastructures. In recent years, they have been exposed to extreme stress due to the increasing demand, the introduction of distributed renewable energy sources, and the development of extensive interconnections. We investigate the phenomenon of abrupt breakdown of an electric power-system under two scenarios: load growth (mimicking the ever-increasing customer demand) and power fluctuations (mimicking the effects of renewable sources). Our results indicate that increasing the system size causes breakdowns to become more abrupt; in fact, mapping the system to a solvable statistical-physics model indicates the occurrence of a first order transition in the large size limit. Such an enhancement for the systemic risk failures (black-outs) with increasing network size is an effect that should be considered in the current projects aiming to integrate national power-grids into "super-grids".

  14. Theory and models of material erosion and lifetime during plasma instabilities in a tokamak environment.

    SciTech Connect (OSTI)

    Hassanein, A.; Konkashbaev, I.

    1999-11-08T23:59:59.000Z

    Surface and structural damage to plasma-facing components (PFCs) due to the frequent loss of plasma confinement remains a serious problem for the tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure, and frequent plasma contamination. Surface damage consists of vaporization, spallation, and liquid splatter of metallic materials. Structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. To evaluate the lifetimes of plasma-facing materials and nearby components and to predict the various forms of damage that they experience, comprehensive models (contained in the HEIGHTS computer simulation package) are developed, integrated self-consistently, and enhanced. Splashing mechanisms such as bubble boiling and various liquid magnetohydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials are being examined. The design requirements and implications of plasma-facing and nearby components are discussed, along with recommendations to mitigate and reduce the effects of plasma instabilities on reactor components.

  15. Multiscale Modeling of Materials - Concepts and Illustration

    E-Print Network [OSTI]

    Aditi Mallik; Keith Runge; James W. Dufty; Hai-Ping Cheng

    2005-07-24T23:59:59.000Z

    The approximate representation of a quantum solid as an equivalent composite semi-classical solid is considered for insulating materials. The composite is comprised of point ions moving on a potential energy surface. In the classical bulk domain this potential energy is represented by pair potentials constructed to give the same structure and elastic properties as the underlying quantum solid. In a small local quantum domain the potential is determined from a detailed quantum calculation of the electronic structure. The primary new ingredients are 1) a determination of the pair potential from quantum data for equilibrium and strained structures, 2) development of pseudo-atoms for a realistic treatment of charge densities where bonds have been broken to define the quantum domain, and 3) inclusion of polarization effects on the quantum domain due to its environment. This formal structure is illustrated in detail for an silica nanorod. For each configuration considered, the charge density of the entire solid is calculated quantum mechanically to provide the reference by which to judge the accuracy of the modeling.It is then shown that the quantum rod, the rod constructed from the classical pair potentials, and the composite classical/quantum rod all have the same equilibrium structure and response to elastic strain. The accuracy of the modeling is shown to apply for two quite different quantum chemical methods for the underlying quantum mechanics: transfer Hamiltonian and density functional methods.

  16. Computational modeling of materials processing and processes

    SciTech Connect (OSTI)

    Lowe, T.C.; Zhu, Yuntian; Bingert, J.F. [and others

    1998-12-31T23:59:59.000Z

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Anisotropic mechanical properties of densified BSCCO powders are of paramount importance during thermo-mechanical processing of superconducting tapes and wires. Maximum current transport requires high relative density and a high degree of alignment of the single crystal planes of the BSCCO. Unfortunately this configuration causes high stresses that can lead to cracking, and thus reduce the density, and the conductive properties of the tape. The current work develops a micromechanical material mode to model is calibrated and compared to experimental results, and then employed to analyze the effects of initial texture and confinement pressure and shear strains in the core of oxide powder-in-tube (OPIT) processed tapes are calculated by finite-element analysis. The calculated deformations were then applied as boundary conditions to the micromechanical model. Our calculated results were used to interpret a set of prototypical rolling experiments. 11 refs., 5 figs.

  17. Cascading Dynamics and Mitigation Assessment in Power System Disturbances via a Hidden Failure Model

    E-Print Network [OSTI]

    ; Protective Relaying hidden failures; Blackout mitigation Introduction An overriding factor in power system failures in protective relays and their impact on power transmission system reliability have been examined shown that over a long interval, more than 70% of the major disturbances involved relaying systems

  18. Modeling the pressure increase in liquid helium cryostats after failure of the insulating vacuum

    SciTech Connect (OSTI)

    Heidt, C.; Grohmann, S. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany and Karlsruhe Institute of Technology, Institute for Technical Thermodynamics and Refrigeration, Engler-Bunte (Germany); Süßer, M. [Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2014-01-29T23:59:59.000Z

    The pressure relief system of liquid helium cryostats requires a careful design, due to helium's low enthalpy of vaporization and due to the low operating temperature. Hazard analyses often involve the failure of the insulating vacuum in the worst-case scenario. The venting of the insulating vacuum and the implications for the pressure increase in the helium vessel, however, have not yet been fully analyzed. Therefore, the dimensioning of safety devices often requires experience and reference to very few experimental data. In order to provide a better foundation for the design of cryogenic pressure relief systems, this paper presents an analytic approach for the strongly dynamic process induced by the loss of insulating vacuum. The model is based on theoretical considerations and on differential equation modeling. It contains only few simplifying assumptions, which will be further investigated in future experiments. The numerical solutions of example calculations are presented with regard to the heat flux into the helium vessel, the helium pressure increase and the helium flow rate through the pressure relief device. Implications concerning two-phase flow and the influence of kinetic energy are discussed.

  19. On the predictive capability and stability of rubber material models

    E-Print Network [OSTI]

    Zheng, Haining

    2008-01-01T23:59:59.000Z

    Due to the high non-linearity and incompressibility constraint of rubber materials, the predictive capability and stability of rubber material models require specific attention for practical engineering analysis. In this ...

  20. Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP6, Kinetics and Microstructure Modelling, H. K. D. H. Bhadeshia

    E-Print Network [OSTI]

    Cambridge, University of

    Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP6, Kinetics in metallurgy. To form a complete design­technology, it is consequently necessary to re- sort to careful

  1. Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP10, Process Modelling, H. K. D. H. Bhadeshia

    E-Print Network [OSTI]

    Cambridge, University of

    Materials Science & Metallurgy Master of Philosophy, Materials Modelling, Course MP10, Process.­E. Svensson. The metallurgy of the welded joint can be categorised into two major regions, the fusion zone

  2. The tunneling model of laser-induced ionization and its failure at low frequencies

    E-Print Network [OSTI]

    H. R. Reiss

    2014-05-11T23:59:59.000Z

    The tunneling model of ionization applies only to longitudinal fields: quasistatic electric fields that do not propagate. Laser fields are transverse: plane wave fields that possess the ability to propagate. Although there is an approximate connection between the effects of longitudinal and transverse fields in a useful range of frequencies, that equivalence fails completely at very low frequencies. Insight into this breakdown is given by an examination of radiation pressure, which is a unique transverse-field effect whose relative importance increases rapidly as the frequency declines. Radiation pressure can be ascribed to photon momentum, which does not exist for longitudinal fields. Two major consequences are that the near-universal acceptance of a static electric field as the zero frequency limit of a laser field is not correct; and that the numerical solution of the dipole-approximate Schr\\"{o}dinger equation for laser effects is inapplicable as the frequency declines. These problems occur because the magnetic component of the laser field is very important at low frequencies, and hence the dipole approximation is not valid. Some experiments already exist that demonstrate the failure of tunneling concepts at low frequencies.

  3. Validation of Material Models for Automotive Carbon Fiber Composite...

    Broader source: Energy.gov (indexed) [DOE]

    Validation of Material Models for Automotive Carbon Fiber Composite Structures (VMM) Libby Berger (General Motors), Omar Faruque (Ford) Co-Principal Investigators US Automotive...

  4. Water Transport in PEM Fuel Cells: Advanced Modeling, Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Testing and Design Optimization Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization Part of a 100 million fuel cell award...

  5. Water Transport in PEM Fuel Cells: Advanced Modeling, Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Testing, and Design Optimization Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing, and Design Optimization This presentation, which focuses on...

  6. FLUID FLOW MODELING OF RESIN TRANSFER MOLDING FOR COMPOSITE MATERIAL WIND TURBINE BLADE STRUCTURES

    E-Print Network [OSTI]

    FLUID FLOW MODELING OF RESIN TRANSFER MOLDING FOR COMPOSITE MATERIAL WIND TURBINE BLADE STRUCTURES.............................................................................................................7 Composite Materials...................................................................................................7 Material Properties

  7. Detecting and modeling cement failure in high pressure/ high temperature wells using finite-element method

    E-Print Network [OSTI]

    Shahri, Mehdi Abbaszadeh

    2006-04-12T23:59:59.000Z

    conditions and are investigated simultaneously to more accurately predict cement failure. The results of this study show the relevant dependency of stress principles with temperature and pressure. These results clarify the deformation caused by any...

  8. December 6, 1995 A MODEL FOR MATERIALS DATABASES

    E-Print Network [OSTI]

    Wiederhold, Gio

    believe are the most closely related to future development of materials database management. Broadly advanced materials are unsuitable. 5. Interfaces provided by existing database management systemsDecember 6, 1995 A MODEL FOR MATERIALS DATABASES Gio Wiederhold Laie Caindec John McCarthy Ken

  9. Fusion materials modeling: Challenges and opportunities

    E-Print Network [OSTI]

    Wirth, B. D.

    The plasma facing components, first wall, and blanket systems of future tokamak-based fusion power plants arguably represent the single greatest materials engineering challenge of all time. Indeed, the United States National ...

  10. Materialized community ground models for large-scale earthquake simulation

    E-Print Network [OSTI]

    Shewchuk, Jonathan

    Materialized community ground models for large-scale earthquake simulation Steven W. Schlosser to ground motion sim- ulations, in which ground model datasets are fully materi- alized into octress stored as a service techniques in which scientific computation and storage services become more tightly intertwined. 1

  11. Novel approaches to multiscale modelling in materials science

    E-Print Network [OSTI]

    Elliott, James

    of nanocrystalline metals and alloys, crack propagation in brittle solids, polymer chain relaxation in nanocomposites, Materials modelling, Molecular dynamics, Monte Carlo, Finite element analysis, Hierarchical/hybrid models in polymer nanocomposites and the control of nucleation in biomimetic materials is also given. Many

  12. NON-DESTRUCTIVE FAILURE PREDICTION FOR BRITTLE SOLIDS

    E-Print Network [OSTI]

    Evans, A.G.

    2013-01-01T23:59:59.000Z

    on the basis of detailed failure analyses conducted on thisprobabilities enter the analysis: the failure probability,failure model, Such techniques involve the detection and analysis

  13. Digital control systems in nuclear power plants: Failure information, modeling concepts, and applications. Revision 1

    SciTech Connect (OSTI)

    Galyean, W.J.

    1993-06-23T23:59:59.000Z

    This report briefly describes some current applications of advanced computerized digital display and control systems at US commercial nuclear power plants and presents the results of a literature search that was made to gather information on the reliability of these systems. Both hardware and software reliability were addressed in this review. Only limited failure rate information was found, with the chemical process industry being the primary source of information on hardware failure rates and expert opinion the primary source for software failure rates. Safety-grade digital control systems are typically installed on a functional like-for-like basis, replacing older analog systems without substantially changing interactions with other plant systems. Future work includes performing a limited probabilistic risk assessment of a representative DCS to assess its risk significance.

  14. Digital control systems in nuclear power plants: Failure information, modeling concepts, and applications

    SciTech Connect (OSTI)

    Galyean, W.J.

    1993-06-23T23:59:59.000Z

    This report briefly describes some current applications of advanced computerized digital display and control systems at US commercial nuclear power plants and presents the results of a literature search that was made to gather information on the reliability of these systems. Both hardware and software reliability were addressed in this review. Only limited failure rate information was found, with the chemical process industry being the primary source of information on hardware failure rates and expert opinion the primary source for software failure rates. Safety-grade digital control systems are typically installed on a functional like-for-like basis, replacing older analog systems without substantially changing interactions with other plant systems. Future work includes performing a limited probabilistic risk assessment of a representative DCS to assess its risk significance.

  15. Preprint December 2003 A Loading-Dependent Model of Probabilistic Cascading Failure

    E-Print Network [OSTI]

    of a large cascading failure. Keywords: Blackout; Electric power transmission system; Infrastructure; Power Benjamin A. Carreras David E. Newman Abstract: Large blackouts of electric power transmission systems- outs of electric power transmission systems. For exam- ple, long, intricate cascades of events caused

  16. Combining Functional Modelling and Qualitative Fault Propagation to Enable Failure Mode Analysis of

    E-Print Network [OSTI]

    Snooke, Neal

    of Software Systems Neal Snooke and Jonathan Bell 1 Abstract. Failure Modes and Effects Analysis (FMEA- ware, and qualitative fault propagation, enables automated Software FMEA (SFMEA). The result is a broad in extending FMEA into the soft- ware itself [3, 14, 6, 8] however there has been little progress in developing

  17. Using Failure Models for Controlling Data Availability in Wireless Sensor Networks

    E-Print Network [OSTI]

    Kravets, Robin

    life-cycle, batteries are charged and nodes have just been tested, so the failure probability of a node how the solution provided by Pirrus achieves good performance with a sustainable computational cost, such as depletion of the available battery energy, hardware defects in the node and harsh environmental conditions

  18. Materials Theory, Modeling and Simulation | ORNL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighand Retrievals from a New 183-GHzMARSecurityMaterialsMPA » MPA-11

  19. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.

    SciTech Connect (OSTI)

    Dunn, Martin L. (University of Colorado, Boulder, CO); Talmage, Mellisa J. (University of Colorado, Boulder, CO); McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO); Spark, Kevin (University of Colorado, Boulder, CO); Diao, Jiankuai (University of Colorado, Boulder, CO); Horstemeyer, Mark F. (Mississippi State University , MS); Zimmerman, Jonathan A.; Gall, K (Georgia Institute of Technology, Atlanta, GA)

    2006-10-01T23:59:59.000Z

    Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

  20. Electrochemical Modeling of LMR-NMC Materials and Electrodes

    Broader source: Energy.gov (indexed) [DOE]

    Modeling of LMR-NMC Materials and Electrodes Project ID: ES189 Presented by Dennis Dees Voltage Fade Team and CAMP Facility Team 2014 DOE Vehicle Technologies Office Annual Merit...

  1. A continuum constitutive model for amorphous metallic materials

    E-Print Network [OSTI]

    Su, Cheng, Ph. D. Massachusetts Institute of Technology

    2007-01-01T23:59:59.000Z

    A finite-deformation, Coulomb-Mohr type constitutive theory for the elastic-viscoplastic response of pressure-sensitive and plastically-dilatant isotropic materials has been developed. The constitutive model has been ...

  2. Calibrating the Abaqus Crushable Foam Material Model using UNM Data

    SciTech Connect (OSTI)

    Schembri, Philip E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Matthew W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-27T23:59:59.000Z

    Triaxial test data from the University of New Mexico and uniaxial test data from W-14 is used to calibrate the Abaqus crushable foam material model to represent the syntactic foam comprised of APO-BMI matrix and carbon microballoons used in the W76. The material model is an elasto-plasticity model in which the yield strength depends on pressure. Both the elastic properties and the yield stress are estimated by fitting a line to the elastic region of each test response. The model parameters are fit to the data (in a non-rigorous way) to provide both a conservative and not-conservative material model. The model is verified to perform as intended by comparing the values of pressure and shear stress at yield, as well as the shear and volumetric stress-strain response, to the test data.

  3. Geometric control of failure behavior in perforated sheets

    E-Print Network [OSTI]

    Michelle M. Driscoll

    2014-11-20T23:59:59.000Z

    Adding perforations to a continuum sheet allows new modes of deformation, and thus modifies its elastic behavior. The failure behavior of such a perforated sheet is explored, using a model experimental system: a material containing a one-dimensional array of rectangular holes. In this model system, a transition in failure mode occurs as the spacing and aspect ratio of the holes are varied: rapid failure via a running crack is completely replaced by quasi-static failure which proceeds via the breaking of struts at random positions in the array of holes. I demonstrate that this transition can be connected to the loss of stress enhancement which occurs as the material geometry is modified.

  4. Dynamic failure of metallic pyramidal truss core materials Experiments and modeling

    E-Print Network [OSTI]

    Barthelat, Francois

    ) buckling induced lateral motion. These findings are con- sistent with prior theoretical and computational and buckling of truss struts played a significant role. This effect appears to dominate the early truss core plastic wave propagation and column buckling. Journal of Applied Mechanics 72 (1), 1­8]. At larger

  5. A multifluid mix model with material strength effects

    SciTech Connect (OSTI)

    Chang, C. H. [Los Alamos National Laboratory; Scannapieco, A. J. [Los Alamos National Laboratory

    2012-04-23T23:59:59.000Z

    We present a new multifluid mix model. Its features include material strength effects and pressure and temperature nonequilibrium between mixing materials. It is applicable to both interpenetration and demixing of immiscible fluids and diffusion of miscible fluids. The presented model exhibits the appropriate smooth transition in mathematical form as the mixture evolves from multiphase to molecular mixing, extending its applicability to the intermediate stages in which both types of mixing are present. Virtual mass force and momentum exchange have been generalized for heterogeneous multimaterial mixtures. The compression work has been extended so that the resulting species energy equations are consistent with the pressure force and material strength.

  6. Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

    SciTech Connect (OSTI)

    Hancock, David, W.

    2012-02-14T23:59:59.000Z

    Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology for air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed over the course of this project could be used to drive fuel cell commercialization. The fuel cell system studied in this project was Plug Power's commercially available GenDrive platform providing battery replacement for equipment in the material handling industry. The fuel cell stacks were Ballard's commercially available FCvelocity 9SSL (9SSL) liquid-cooled PEM fuel cell stack and FCvelocity 1020ACS (Mk1020) air-cooled PEM fuel cell stack.

  7. Modeling of Sulfate Resistance of Flyash Blended Cement Concrete Materials

    E-Print Network [OSTI]

    Mobasher, Barzin

    Modeling of Sulfate Resistance of Flyash Blended Cement Concrete Materials Barzin Mobasher1. A simplified model is presented which used cement chemistry, concrete physics, and mechanics to develop of hardened concrete, principally the cement paste, caused by exposure of concrete to sulfates and moisture

  8. TAMCN: a tool for aggregate modeling of civil nuclear materials

    E-Print Network [OSTI]

    Watson, Aaron Michael

    2002-01-01T23:59:59.000Z

    substantial quantity of material to the amount of civil separated plutonium present today, so we thought it wise to begin here. We have developed a model of the nuclear fuel cycle in Western Europe and Japan using STELLA®. Our model uses the simple "stock...

  9. A physically-based abrasive wear model for composite materials

    SciTech Connect (OSTI)

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01T23:59:59.000Z

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  10. Application Of A New Semi-Empirical Model For Forming Limit Prediction Of Sheet Material Including Superposed Loads Of Bending And Shearing

    SciTech Connect (OSTI)

    Held, Christian [Hochschul Institute Neckarsulm, Gottlieb-Daimler-Strasse 40, 74172 Neckarsulm (Germany); Liewald, Mathias; Schleich, Ralf [Institute for Metal Forming Technology, Universitaet Stuttgart, Stuttgart (Germany); Sindel, Manfred [AUDI AG, Neckarsulm (Germany)

    2010-06-15T23:59:59.000Z

    The use of lightweight materials offers substantial strength and weight advantages in car body design. Unfortunately such kinds of sheet material are more susceptible to wrinkling, spring back and fracture during press shop operations. For characterization of capability of sheet material dedicated to deep drawing processes in the automotive industry, mainly Forming Limit Diagrams (FLD) are used. However, new investigations at the Institute for Metal Forming Technology have shown that High Strength Steel Sheet Material and Aluminum Alloys show increased formability in case of bending loads are superposed to stretching loads. Likewise, by superposing shearing on in plane uniaxial or biaxial tension formability changes because of materials crystallographic texture. Such mixed stress and strain conditions including bending and shearing effects can occur in deep-drawing processes of complex car body parts as well as subsequent forming operations like flanging. But changes in formability cannot be described by using the conventional FLC. Hence, for purpose of improvement of failure prediction in numerical simulation codes significant failure criteria for these strain conditions are missing. Considering such aspects in defining suitable failure criteria which is easy to implement into FEA a new semi-empirical model has been developed considering the effect of bending and shearing in sheet metals formability. This failure criterion consists of the combination of the so called cFLC (combined Forming Limit Curve), which considers superposed bending load conditions and the SFLC (Shear Forming Limit Curve), which again includes the effect of shearing on sheet metal's formability.

  11. A method for estimating common cause failure probability and model parameters : the inverse stress-strength interference (ISSI) technique

    E-Print Network [OSTI]

    Guey, Ching Ning

    1984-01-01T23:59:59.000Z

    In this study, an alternative for the analysis of common cause failures (CCFs) is investigated. The method studied consists of using the Licensee Event Report (LER) data to get single component failure probability and using ...

  12. Modeling thermal/chemical/mechanical response of energetic materials

    SciTech Connect (OSTI)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J. [and others

    1995-07-01T23:59:59.000Z

    An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.

  13. Compendium of Material Composition Data for Radiation Transport Modeling

    SciTech Connect (OSTI)

    McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert

    2011-03-04T23:59:59.000Z

    Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library file or mechanism for revising the data in a consistent and traceable manner. The authors of this revision have addressed that problem by first compiling all of the information (i.e., numbers and references) for all the materials into a single database, maintained at PNNL, that was then used as the basis for this document.

  14. Dielectric breakdown model for composite materials F. Peruani,1

    E-Print Network [OSTI]

    Peruani, Fernando

    Dielectric breakdown model for composite materials F. Peruani,1 G. Solovey,1 I. M. Irurzun,1,2 E. E on the breakdown of fuse net- works, while others have concentrated on dielectric break- down in networks. Mola,2, * A. Marzocca,1 and J. L. Vicente2 1 Departamento de Fisica, ``Juan Jose´ Giambiagi,'' FCEy

  15. A network model of parametric working memory. Supplementary Material

    E-Print Network [OSTI]

    Brody, Carlos

    obeys the current balance equation: CM dVi dt = -gL [Vi - VL]-gESE,i [Vi - VE]-gISI,i [Vi - VIA network model of parametric working memory. Supplementary Material Paul Miller1 , Carlos D Brody2

  16. Failure modes at room and elevated temperatures. Technical report

    SciTech Connect (OSTI)

    Braun, L.M.

    1995-04-01T23:59:59.000Z

    Successful development of reliable ceramic composites will depend on an understanding of matrix cracking and damage mechanisms in these materials. Therefore, the objective of the Failure Models subtask is to investigate failure and damage mechanisms in fiber reinforced ceramic composites. Issues such as how fiber coatings, the fiber/matrix interface, residual stresses, and fiber volume fraction affect frictional stresses, fiber debonding, fiber pull-out and failure modes will be examined. The effect of these microstructural parameters on matrix crack initiation, propagation and damage will also be determined. The resulting observations and measurements data will be used to develop theoretical models for damage mechanisms in fiber reinforced composites. This report presents results concerning the effect of temperature on the failure modes of continuous fiber ceramic composites performed during the last quarter of FY 1993 and FY 1994. The Raman stress measurements and calculations were performed during the last quarter of FY 1994 and the first quarter of FY 1995.

  17. Seismic Performance, Modeling, and Failure Assessment of Reinforced Concrete Shear Wall Buildings

    E-Print Network [OSTI]

    Tuna, Zeynep

    2012-01-01T23:59:59.000Z

    J.W. , (2009). Testing and Reinforced Concrete Coupling2010). "Testing and Modeling of Reinforced Concrete Couplingscale testing of four-story reinforced concrete and post-

  18. Exascale Co-design for Modeling Materials in Extreme Environments

    SciTech Connect (OSTI)

    Germann, Timothy C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-08T23:59:59.000Z

    Computational materials science has provided great insight into the response of materials under extreme conditions that are difficult to probe experimentally. For example, shock-induced plasticity and phase transformation processes in single-crystal and nanocrystalline metals have been widely studied via large-scale molecular dynamics simulations, and many of these predictions are beginning to be tested at advanced 4th generation light sources such as the Advanced Photon Source (APS) and Linac Coherent Light Source (LCLS). I will describe our simulation predictions and their recent verification at LCLS, outstanding challenges in modeling the response of materials to extreme mechanical and radiation environments, and our efforts to tackle these as part of the multi-institutional, multi-disciplinary Exascale Co-design Center for Materials in Extreme Environments (ExMatEx). ExMatEx has initiated an early and deep collaboration between domain (computational materials) scientists, applied mathematicians, computer scientists, and hardware architects, in order to establish the relationships between algorithms, software stacks, and architectures needed to enable exascale-ready materials science application codes within the next decade. We anticipate that we will be able to exploit hierarchical, heterogeneous architectures to achieve more realistic large-scale simulations with adaptive physics refinement, and are using tractable application scale-bridging proxy application testbeds to assess new approaches and requirements. Such current scale-bridging strategies accumulate (or recompute) a distributed response database from fine-scale calculations, in a top-down rather than bottom-up multiscale approach.

  19. A 4D geometrical modeling of a material aging

    E-Print Network [OSTI]

    A. Chudnovsky; S. Preston

    2006-04-16T23:59:59.000Z

    4-dim intrinsic (material) Riemannian metric $G$ of the material 4-D space-time continuum $P$ is utilized as the characteristic of the aging processes developing in the material. Manifested through variation of basic material characteristics such as density, moduli of elasticity, yield stress, strength, and toughness., the aging process is modeled as the evolution of the metric $G$ (most importantly of its time component $G_{00}$) of the material space-time $P$ embedded into 4-D Newtonian space-time with Euclidean metric.\\par The evolutional equation for metric $G$ is derived by the classical variational approach. Construction of a Lagrangian for an aging elastic media and the derivation of a system of coupled elastostatic and aging equations constitute the central part of the work. The external and internal balance laws associated with symmetries of material and physical space-time geometries are briefly reviewed from a new viewpoint presented in the paper. Examples of the stress relaxation and creep of a homogeneous rod, cold drawing, and chemical degradation in a tubing are discussed.

  20. Modeling shear failure and permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs

    SciTech Connect (OSTI)

    Kelkar, Sharad [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of an Enhanced Geothermal System (EGS). Rock deformation and in-situ stress changes induced by injected fluids can lead to shear failure on preexisting fractures which can generate microseismic events, and also enhance the permeability and accessible surface area of the geothermal formation. Hence, the ability to accurately model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. The locations of the microseismic events can serve as indicators of the zones of enhanced permeability, thus providing vital information for verification of the coupled THM models. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled THM processes during multiphase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method.

  1. Evaluation of a semi-implicit numerical algorithm for a rate-dependent ductile failure model.

    SciTech Connect (OSTI)

    Zocher, M. A. (Marvin Anthony); Zuo, Q. K. (Qiuhai K.); Mason, T. A. (Thomas A.)

    2002-09-01T23:59:59.000Z

    A survey conducted in the mid-80's revealed that the mathematical descriptions of ductile fracture tended to apply to either tensile tests or spa11 tests. The objective behind the development of the TEPLA was then a unification of these disparate phenomena into a single model.

  2. Model-based Failure Modes and Effects Analysis of Neal Snooke 1

    E-Print Network [OSTI]

    Snooke, Neal

    embedded software developers who are already familiar with the benefits of FMEA analysis. Several au- thors discuss experiences of performing manual FMEA of software however there has been no attempt at automating of software and the success of model based automated FMEA for hardware. 1 Introduction The notion of Software

  3. Micromechanical Damage Models for Continuous Fiber Reinforced Composite Materials

    E-Print Network [OSTI]

    Wu, Yi

    2013-01-01T23:59:59.000Z

    plastic matrix composite, Material and Design, 31: Zhou,scheme for composite materials, International Journal ofelastic energy of materials with misfitting inclusions, Acta

  4. Modeling Creep-Fatigue-Environment Interactions in Steam Turbine Rotor Materials for Advanced Ultra-supercritical Coal Power Plants

    SciTech Connect (OSTI)

    Shen, Chen

    2014-01-20T23:59:59.000Z

    The goal of this project is to model creep-fatigue-environment interactions in steam turbine rotor materials for advanced ultra-supercritical (A-USC) coal power Alloy 282 plants, to develop and demonstrate computational algorithms for alloy property predictions, and to determine and model key mechanisms that contribute to the damages caused by creep-fatigue-environment interactions. The nickel based Alloy 282 is selected for this project because it is one of the leading candidate materials for the high temperature/pressure section of an A-USC steam turbine. The methods developed in the project are expected to be applicable to other metal alloys in similar steam/oxidation environments. The major developments are: ? failure mechanism and microstructural characterization ? atomistic and first principles modeling of crack tip oxygen embrittlement ? modeling of gamma prime microstructures and mesoscale microstructure-defect interactions ? microstructure and damage-based creep prediction ? multi-scale crack growth modeling considering oxidation, viscoplasticity and fatigue The technology developed in this project is expected to enable more accurate prediction of long service life of advanced alloys for A-USC power plants, and provide faster and more effective materials design, development, and implementation than current state-of-the-art computational and experimental methods. This document is a final technical report for the project, covering efforts conducted from January 2011 to January 2014.

  5. 8. MATERIAL MODELLING Abstract --The aim of this study consists in modelling the

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to more severe operating conditions. Because of self-heating due to losses or the proximity of heat electrical application where skin effect in the material is insignificant, a macroscopic dynamical model (1

  6. Modeling air emissions from contaminated sediment dredged materials

    SciTech Connect (OSTI)

    Valsaraj, K.T.; Thibodeaux, L.J. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Chemical Engineering; Reible, D.D. [Louisiana State Univ., Baton Rouge, LA (United States); [Univ. of Sydney, New South Wales (Australia)

    1995-12-31T23:59:59.000Z

    Volatilization rates for hydrophobic organic compounds from a confined disposal facility (CDF) containing contaminated dredged material are presently unknown. The primary purpose of this study is to indicate the availability of theoretical models for the evaluation of volatile emission from a CDF. Four emission locales are identified and modeled: the sediment relocation (dredging) locale, the exposed sediment locale, the ponded sediment locale, and the vegetation-covered sediment locale. Rate expressions are derived to estimate the volatile organic chemical (VOC) emission from each locale. Emission rates (in mass of total VOCs per unit time) are primarily dependent on the chemical concentration at the source, the surface area of the source, and the degree to which the dredged material is in direct contact with air. The relative magnitude of these three parameters provides a basis upon which a tentative ranking of emission rates from the different locales can be given. Exposed sediment results in the greatest estimated emissions of volatiles followed by water with high levels of suspended sediments, such as might occur during dredging or during placement in a CDF. Expected to be lower in volatile emissions are dredged materials covered by a quiescent water column or vegetation.

  7. Sandia National Laboratories: Sandian Presents on PV Failure...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Modeling & SimulationSandian Presents on PV Failure Analysis at European PV Solar Energy Conference and Exhibition (EU PVSC) Sandian Presents on PV Failure Analysis...

  8. RECERTIFICATION OF THE MODEL 9977 RADIOACTIVE MATERIAL PACKAGING

    SciTech Connect (OSTI)

    Abramczyk, G.; Bellamy, S.; Loftin, B.; Nathan, S.

    2013-06-05T23:59:59.000Z

    The Model 9977 Packaging was initially issued a Certificate of Compliance (CoC) by the Department of Energy’s Office of Environmental Management (DOE-EM) for the transportation of radioactive material (RAM) in the Fall of 2007. This first CoC was for a single radioactive material and two packing configurations. In the five years since that time, seven Addendums have been written to the Safety Analysis Report for Packaging (SARP) and five Letter Amendments have been written that have authorized either new RAM contents or packing configurations, or both. This paper will discuss the process of updating the 9977 SARP to include all the contents and configurations, including the addition of a new content, and its submittal for recertification.

  9. Report for the ASC CSSE L2 Milestone (4873) - Demonstration of Local Failure Local Recovery Resilient Programming Model.

    SciTech Connect (OSTI)

    Heroux, Michael A.; Teranishi, Keita [Sandia National Laboratories, Livermore, CA

    2014-06-01T23:59:59.000Z

    Recovery from process loss during the execution of a distributed memory parallel application is presently achieved by restarting the program, typically from a checkpoint file. Future computer system trends indicate that the size of data to checkpoint, the lack of improvement in parallel file system performance and the increase in process failure rates will lead to situations where checkpoint restart becomes infeasible. In this report we describe and prototype the use of a new application level resilient computing model that manages persistent storage of local state for each process such that, if a process fails, recovery can be performed locally without requiring access to a global checkpoint file. LFLR provides application developers with an ability to recover locally and continue application execution when a process is lost. This report discusses what features are required from the hardware, OS and runtime layers, and what approaches application developers might use in the design of future codes, including a demonstration of LFLR-enabled MiniFE code from the Matenvo mini-application suite.

  10. Materials Science and Engineering A, 2011, 528(1-2): p. 7596 7605 High strain rate compressive response ofsyntactic foams: trends in mechanical properties and failure mechanisms

    E-Print Network [OSTI]

    Gupta, Nikhil

    comprising hollow particles dispersed in a matrix material. Available studies on high strain rate compressive with respect to the material composition. Syntactic foams reinforced with micro- and nano-sized fibers are a class of porous materials in which thin-walled hollow particles are dispersed in a matrix material

  11. CASTING DEFECT MODELING IN AN INTEGRATED COMPUTATIONAL MATERIALS ENGINEERING APPROACH

    SciTech Connect (OSTI)

    Sabau, Adrian S [ORNL

    2015-01-01T23:59:59.000Z

    To accelerate the introduction of new cast alloys, the simultaneous modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. The required models related to casting defects, such as microporosity and hot tears, are reviewed. Three aluminum alloys are considered A356, 356 and 319. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Examples are given for predicting microporosity defects and microstructure distribution for a plate casting. Models to predict fatigue life and yield stress are briefly highlighted here for the sake of completion and to illustrate how the length scales of the microstructure features as well as porosity defects are taken into account for modeling the mechanical properties. Thus, the data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the component. ACKNOWLEDGEMENTS This work was performed under a Cooperative Research and Development Agreement (CRADA) with the Nemak Inc., and Chrysler Co. for the project "High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines. The author would also like to thank Amit Shyam for reviewing the paper and Andres Rodriguez of Nemak Inc. Research sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, as part of the Propulsion Materials Program under contract DE-AC05-00OR22725 with UT-Battelle, LLC. Part of this research was conducted through the Oak Ridge National Laboratory's High Temperature Materials Laboratory User Program, which is sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.

  12. Concrete Material Models Concrete_1: Concrete Model with No Tensile Strength

    E-Print Network [OSTI]

    Filippou, Filip C.

    Concrete Material Models Concrete_1: Concrete Model with No Tensile Strength INPUT Concrete_1, matID ¢f fc cu u, , ,e e0 Definitions (Fig. 1): fc : concrete compressive strength at 28 days (compression is negative) A0 : concrete strain at maximum strength (compression is negative) fcu : concrete crushing

  13. MASTER OF PHILOSOPHY, Modelling of Materials Friday 26th April 2002 9 12

    E-Print Network [OSTI]

    Cambridge, University of

    MASTER OF PHILOSOPHY, Modelling of Materials Friday 26th April 2002 9 ­ 12 MODELLING OF MATERIALS of the valence electrons. (e) FORTRAN is a contraction of "formula translation." What features of the language exam- ples. (f) Materials modelling is applied over a wide range of length scales, from an atom

  14. An Ion Diffusion Model in Semi-Permeable Clay Materials. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Here we proposed a model by coupling electrodynamics and nonequilibrium thermodynamics to describe ion diffusion in the clay materials. The developed model was validated...

  15. Abduction Compared with Negation by Failure

    E-Print Network [OSTI]

    Koehn, Philipp

    Abduction Compared with Negation by Failure K. Eshghi * Hewlett Packard Laboratories programming can be extended to include abduction with integrity constraints. In the resulting extension for negation by failure, which generalises the stable model semantics of negation by failure. The abductive

  16. FEMA: a Finite Element Model of Material Transport through Aquifers

    SciTech Connect (OSTI)

    Yeh, G.T.; Huff, D.D.

    1985-01-01T23:59:59.000Z

    This report documents the construction, verification, and demonstration of a Finite Element Model of Material Transport through Aquifers (FEMA). The particular features of FEMA are its versatility and flexibility to deal with as many real-world problems as possible. Mechanisms included in FEMA are: carrier fluid advection, hydrodynamic dispersion and molecular diffusion, radioactive decay, sorption, source/sinks, and degradation due to biological, chemical as well as physical processes. Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Prescribed concentration on the Dirichlet boundary, given gradient on the Neumann boundary segment, and flux at each Cauchy boundary segment can vary independently of each other. The aquifer may consist of as many formations as desired. Either completely confined or completely unconfined or partially confined and partially unconfined aquifers can be dealt with effectively. FEMA also includes transient leakage to or from the aquifer of interest through confining beds from or to aquifers lying below and/or above.

  17. Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding, material microstructure and properties in friction stir welding welds of AA5083 (a non welding, Johnson-Cook material model 1. Introduction In this study, an attempt is made to modify

  18. Modeling and Simulation of Hazardous Material Releases for Homeland Security Applications

    E-Print Network [OSTI]

    Magee, Joseph W.

    i Modeling and Simulation of Hazardous Material Releases for Homeland Security Applications DRAFT in the breakout track on Hazardous Material Release at the workshop on Homeland Security Modeling & Simulation...........................................................................................................................................................1 2. Introduction to Hazardous Material Releases (HMR) and Associated DHS Guidance

  19. Modeling the thermoelectric properties of bulk and nanocomposite thermoelectric materials

    E-Print Network [OSTI]

    Minnich, Austin (Austin Jerome)

    2008-01-01T23:59:59.000Z

    Thermoelectric materials are materials which are capable of converting heat directly into electricity. They have long been used in specialized fields where high reliability is needed, such as space power generation. Recently, ...

  20. Application for managing model-based material properties for simulation-based engineering

    DOE Patents [OSTI]

    Hoffman, Edward L. (Alameda, CA)

    2009-03-03T23:59:59.000Z

    An application for generating a property set associated with a constitutive model of a material includes a first program module adapted to receive test data associated with the material and to extract loading conditions from the test data. A material model driver is adapted to receive the loading conditions and a property set and operable in response to the loading conditions and the property set to generate a model response for the material. A numerical optimization module is adapted to receive the test data and the model response and operable in response to the test data and the model response to generate the property set.

  1. A review of macroscopic ductile failure criteria.

    SciTech Connect (OSTI)

    Corona, Edmundo; Reedlunn, Benjamin

    2013-09-01T23:59:59.000Z

    The objective of this work was to describe several of the ductile failure criteria com- monly used to solve practical problems. The following failure models were considered: equivalent plastic strain, equivalent plastic strain in tension, maximum shear, Mohr- Coulomb, Wellman's tearing parameter, Johnson-Cook and BCJ MEM. The document presents the main characteristics of each failure model as well as sample failure predic- tions for simple proportional loading stress histories in three dimensions and in plane stress. Plasticity calculations prior to failure were conducted with a simple, linear hardening, J2 plasticity model. The resulting failure envelopes were plotted in prin- cipal stress space and plastic strain space, where the dependence on stress triaxiality and Lode angle are clearly visible. This information may help analysts select a ductile fracture model for a practical problem and help interpret analysis results.

  2. Light water reactor lower head failure analysis

    SciTech Connect (OSTI)

    Rempe, J.L.; Chavez, S.A.; Thinnes, G.L. [EG and G Idaho, Inc., Idaho Falls, ID (United States)] [and others

    1993-10-01T23:59:59.000Z

    This document presents the results from a US Nuclear Regulatory Commission-sponsored research program to investigate the mode and timing of vessel lower head failure. Major objectives of the analysis were to identify plausible failure mechanisms and to develop a method for determining which failure mode would occur first in different light water reactor designs and accident conditions. Failure mechanisms, such as tube ejection, tube rupture, global vessel failure, and localized vessel creep rupture, were studied. Newly developed models and existing models were applied to predict which failure mechanism would occur first in various severe accident scenarios. So that a broader range of conditions could be considered simultaneously, calculations relied heavily on models with closed-form or simplified numerical solution techniques. Finite element techniques-were employed for analytical model verification and examining more detailed phenomena. High-temperature creep and tensile data were obtained for predicting vessel and penetration structural response.

  3. Solar Thermal Reactor Materials Characterization

    SciTech Connect (OSTI)

    Lichty, P. R.; Scott, A. M.; Perkins, C. M.; Bingham, C.; Weimer, A. W.

    2008-03-01T23:59:59.000Z

    Current research into hydrogen production through high temperature metal oxide water splitting cycles has created a need for robust high temperature materials. Such cycles are further enhanced by the use of concentrated solar energy as a power source. However, samples subjected to concentrated solar radiation exhibited lifetimes much shorter than expected. Characterization of the power and flux distributions representative of the High Flux Solar Furnace(HFSF) at the National Renewable Energy Laboratory(NREL) were compared to ray trace modeling of the facility. In addition, samples of candidate reactor materials were thermally cycled at the HFSF and tensile failure testing was performed to quantify material degradation. Thermal cycling tests have been completed on super alloy Haynes 214 samples and results indicate that maximum temperature plays a significant role in reduction of strength. The number of cycles was too small to establish long term failure trends for this material due to the high ductility of the material.

  4. Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle material

    E-Print Network [OSTI]

    Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle are derived either at microscale with random distribution of material properties or at a mesoscale

  5. Nanotechnology Nanotechnology comprises measurement, design, modeling and fabrication of materials and systems at the atomic scale.

    E-Print Network [OSTI]

    Glowinski, Roland

    Nanotechnology Nanotechnology comprises measurement, design, modeling and fabrication of materials are able to customize their education by specializing in areas such as nanotechnology, computational

  6. Materials

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home andDisposition | NationalMaterials

  7. Advanced Modeling and Materials in Kraft Pulp Mills

    SciTech Connect (OSTI)

    Keiser, J.R.; Gorog, J.P.

    2002-05-15T23:59:59.000Z

    This CRADA provided technical support to the Weyerhaeuser Company on a number of issues related to the performance and/or selection of materials at a number of locations in a pulp and paper mill. The studies related primarily to components for black liquor recovery boilers, but some effort was directed toward black liquor gasifiers and rolls for paper machines. The purpose of this CRADA was to assist Weyerhaeuser in the evaluation of materials exposed in various paper mill environments and to provide direction in the selection of alternate materials, when appropriate.

  8. Export Failure and its Consequences: Theory and Evidence

    E-Print Network [OSTI]

    Mora, Jesse

    2015-01-01T23:59:59.000Z

    for export success . . . . . . . . . . . . . . . VA Model with Export Failure, Marketing Costs, and Financial2 Export Expansions of Products and Destinations I

  9. Modeling transport of disposed dredged material from placement sites in Grays Harbor, WA

    E-Print Network [OSTI]

    US Army Corps of Engineers

    Modeling transport of disposed dredged material from placement sites in Grays Harbor, WA E- to mid- term dredge material management strategies for the Federal Navigation Project at Grays Harbor dredging quantities. However, the most heavily used dredged material placement sites lie in proximity

  10. Stochastic multiscale models for fracture analysis of functionally graded materials

    E-Print Network [OSTI]

    Rahman, Sharif

    Chakraborty, Sharif Rahman * Department of Mechanical and Industrial Engineering, College of Engineering three multiscale models, including sequential, invasive, and concurrent models, for fracture analysis-intensity factors or accurate probability of fracture initiation. The concurrent multiscale model is sufficiently

  11. Assessing Models of Public Understanding In ELSI Outreach Materials

    SciTech Connect (OSTI)

    Bruce V. Lewenstein, Ph.D.; Dominique Brossard, Ph.D.

    2006-03-01T23:59:59.000Z

    Advances in the science of genetics have implications for individuals and society, and have to be taken into account at the policy level. Studies of ethical, legal and social issues related to genomic research have therefore been integrated in the Human Genome Project (HGP) since the earliest days of the project. Since 1990, three to five percent of the HGP annual budget has been devoted to such studies, under the umbrella of the Ethical, Legal, and Social Implications (ELSI) Programs of the National Human Genome Research Institute of the National Institute of Health, and of the Office of Biological and Environmental Research of the U.S. Department of Energy (DOE). The DOE-ELSI budget has been used to fund a variety of projects that have aimed at ?promoting education and help guide the conduct of genetic research and the development of related medical and public policies? (HGP, 2003). As part of the educational component, a significant portion of DOE-ELSI funds have been dedicated to public outreach projects, with the underlying goal of promoting public awareness and ultimately public discussion of ethical, legal, and social issues surrounding availability of genetic information (Drell, 2002). The essential assumption behind these projects is that greater access to information will lead to more knowledge about ethical, legal and social issues, which in turn will lead to enhanced ability on the part of individuals and communities to deal with these issues when they encounter them. Over the same period of time, new concepts of ?public understanding of science? have emerged in the theoretical realm, moving from a ?deficit? or linear dissemination of popularization, to models stressing lay-knowledge, public engagement and public participation in science policy-making (Lewenstein, 2003). The present project uses the base of DOE-funded ELSI educational project to explore the ways that information about a new and emerging area of science that is intertwined with public issues has been used in educational public settings to affect public understanding of science. After a theoretical background discussion, our approach is three-fold. First, we will provide an overview, a ?map? of DOE-funded of outreach programs within the overall ELSI context to identify the importance of the educational component, and to present the criteria we used to select relevant and representative case studies. Second, we will document the history of the case studies. Finally, we will explore an intertwined set of research questions: (1) To identify what we can expect such projects to accomplish -in other words to determine the goals that can reasonably be achieved by different types of outreach, (2) To point out how the case study approach could be useful for DOE-ELSI outreach as a whole, and (3) To use the case study approach as a basis to test theoretical models of science outreach in order to assess to what extent those models accord with real world outreach activities. For this last goal, we aim at identifying what practices among ELSI outreach activities contribute most to dissemination, or to participation, in other words in which cases outreach materials spark action in terms of public participation in decisions about scientific issues.

  12. Use of UHPC in Bridge Structures: Material Modeling and Design

    E-Print Network [OSTI]

    Gunes, Oguz

    Ultra-high-performance concrete (UHPC) is a promising new class of concrete material that is likely to make a significant contribution to addressing the challenges associated with the load capacity, durability, sustainability, ...

  13. Failure Stress and Apparent Elastic Modulus of Diesel Particulate...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    test specimen geometries and test methods for brittle materials are adapted to DPF architecture to evaluate failure initiation stress and apparent elastic modulus of the ceramics....

  14. Modeling of Damage in Cement-Based Materials Subjected to External Sulfate Attack. I: Formulation

    E-Print Network [OSTI]

    Mobasher, Barzin

    Modeling of Damage in Cement-Based Materials Subjected to External Sulfate Attack. I: Formulation subject headings: Damage; Models; Sulfates; Cements. Introduction A majority of the durability issues. Portland cement-based materials subjected to attack from external sulfates may suffer from two types of dam

  15. A RATE-INDEPENDENT MODEL FOR PERMANENT INELASTIC EFFECTS IN SHAPE MEMORY MATERIALS

    E-Print Network [OSTI]

    Stefanelli, Ulisse

    A RATE-INDEPENDENT MODEL FOR PERMANENT INELASTIC EFFECTS IN SHAPE MEMORY MATERIALS MICHELA ELEUTERI for isothermal stress-induced transforma- tion in shape memory polycrystalline materials in presence of permanent of the model to reduced/former ones by means of a rigorous -convergence analysis. 1. Introduction Shape-memory

  16. Modeling of a Nickel-Hydrogen Cell Phase Reactions in the Nickel Active Material

    E-Print Network [OSTI]

    Modeling of a Nickel-Hydrogen Cell Phase Reactions in the Nickel Active Material B. Wu and R. E of South Carolina, Columbia, South Carolina 29208, USA A nonisothermal model of a nickel-hydrogen cell has been developed with the consideration of multiple phases in the nickel active material. Important

  17. Abstract--The analysis of follow-up data from patients suffering from heart failure is a difficult task, due to the complex and multifactorial nature of this pathology. In this paper, we present a coupled model, integrating a pulsatile heart into a model

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Abstract--The analysis of follow-up data from patients suffering from heart failure a coupled model, integrating a pulsatile heart into a model of the short to long-term regulations decompensated heart failure episode on a patient undergoing cardiac resynchronization therapy. Index Terms

  18. A broken material approach to modeling oil sand under dynamic load Tim Grain Joseph, Ph.D., P.Eng.,

    E-Print Network [OSTI]

    Joseph, Tim Grain

    by Joseph (2003), providing a unique material behaviour relationship, allows the compounding problem and early structural damage via fatigue failure mechanisms. The root cause has been identified by Joseph process to production measurement and structural component life. For the most part this work has

  19. Modeling - Scale-Bridging Simulations Active Materials in Li...

    Broader source: Energy.gov (indexed) [DOE]

    Design Using Coupled Kinetic, Thermal and Mechanical Modeling Overview of the Batteries for Advanced Transportation Technologies (BATT) Program Electrochemistry Diagnostics...

  20. Surface Finish Modeling in Micromilling of Biocompatible Materials

    E-Print Network [OSTI]

    Berestovskyi, Dmytro V

    2013-06-05T23:59:59.000Z

    the requirements listed above. Computer controlled micromilling on a high speed machine system in minimum quantity lubrication was used to remove most materials and define a channel pattern. Microchannels were machined with ball end mills of diameters from Ø152?m...

  1. Surface Finish Modeling in Micromilling of Biocompatible Materials 

    E-Print Network [OSTI]

    Berestovskyi, Dmytro V

    2013-06-05T23:59:59.000Z

    of 6061-T6 Aluminum Alloy and A36 Low Carbon Steel ............................................................................................. 68 Table 10. Solutions for Chemical Etching of 304 Stainless Steel and CP Titanium ....... 72 Table 11... aspect ratio channels. In addition, chemical etching requires 2 intricate expensive mask and utilization of unique chemical solution for each material. This makes the etching process complex and time consuming. Conventional micromilling has...

  2. The Impact of Protection System Failures on Power System Reliability Evaluation 

    E-Print Network [OSTI]

    Jiang, Kai

    2012-11-05T23:59:59.000Z

    Figure 6-11. Reliability modeling of power systems with perfect protections. ............ 145 Figure 6-12. Reliability modeling of power systems with protection failures. ............. 146 Figure 6-13. 24-bus IEEE Reliability Test System (RTS... is reprinted from copyrighted material with permission from IEEE. ?2010 IEEE. Reprinted, with permission, from Kai Jiang and Chanan Singh, ?Reliability modeling of all-digital protection systems including impact of repair?? IEEE Trans. Power Delivery, vol...

  3. Recent advances in modeling discontinuities in anisotropic and heterogeneous materials in eddy current NDE

    SciTech Connect (OSTI)

    Aldrin, John C. [Computational Tools, Gurnee, IL 60031 (United States); Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H. [Victor Technologies LLC, Bloomington, IN 47401 (United States)

    2011-06-23T23:59:59.000Z

    Recent advances are presented to model discontinuities in random anisotropies that arise in certain materials, such as titanium alloys. A numerical model is developed to provide a full anisotropic representation of each crystalline in a gridded region of the material. Several simulated and experimental demonstrations are presented highlighting the effect of grain noise on eddy current measurements. Agreement between VIC-3D(c) model calculations and experimental data in titanium alloy specimens with known flaws is demonstrated.

  4. Summer 2014 Undergraduate Research Experience in Physics: Materials and Modeling

    E-Print Network [OSTI]

    ) nuclear reactor found on a college campus. The MU Research Reactor (MURR) provides advanced research experiments, theory, and modeling and span a variety of research projects (see http

  5. CFD MODELING AND SIMULATION IN MATERIALS PROCESSES Edited by TMS (The Minerals, Metals & Materials Society), 2004

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    Society), 2004 Solidification and Macrosegregation in Aluminum Alloys on Uneven Surfaces Deep Samanta1 school of Mechanical and Aerospace Engineering, Cornell University; Ithaca, NY 14853-3801, USA Keywords of metal aluminum and aluminum alloys is modeled on uneven surfaces char- acterized by sinusoidal curves

  6. Novel failure prognostics approach with dynamic thresholds for machine degradation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Novel failure prognostics approach with dynamic thresholds for machine degradation Kamran Javed-processing and prognostics modeling. To estimate RUL of a degrading machinery, prognostics modeling phase requires precise knowledge about failure thresh- old (FT) (or failure definition). Practically, degrading machinery can have

  7. Scientists use world's fastest computer to model materials under extreme

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebook Twitter PrincipalfuelTorusconditions Materials under extreme

  8. Modeling - Scale-Bridging Simulations Active Materials in Li...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Society, v. 154 (10), pp. A978-A986. 3. Wang, C.-W. and Sastry, A.M., 2007, "Mesoscale Modeling of a Li-Ion Poly Cell," Journal of the Electrochemical Society, v. 154...

  9. MASTER OF PHILOSOPHY Modelling of Materials Examiners' Solutions to Paper 1

    E-Print Network [OSTI]

    Cambridge, University of

    ? ---- Which programming language, compiler or numerical solver ? ---- How fast is the chosen model? How muchMASTER OF PHILOSOPHY Modelling of Materials Examiners' Solutions to Paper 1 SECTION A 1(a) [source are the dependent and independent variables? ---- How empirical should the model be? (i.e. degree of data fitting

  10. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar

    E-Print Network [OSTI]

    Grujicic, Mica

    /multi-length scale architecture of the material microstructure; (b) nonlinear, rate-dependent and often pressure twisting, interfiber friction/sliding, etc. Material models currently employed in the computational under high-deformation rate, large-strain, and high- pressure loading conditions, the conditions

  11. Dielectric breakdown model for conductor-loaded and insulator-loaded composite materials P. Bergero,1

    E-Print Network [OSTI]

    Peruani, Fernando

    Dielectric breakdown model for conductor-loaded and insulator-loaded composite materials P. Bergero strength is highly desirable, and in the past years composite materials such as resin matrix filled- tors, and composites containing carbon black and titanium dioxide have recently been tested

  12. The automatic generation of semantic annotations for didactic materials and the use of models in the material development to improve its reusability

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    The automatic generation of semantic annotations for didactic materials and the use of models.es, aedo@ia.inf.uc3m.es Abstract The didactic material reusability, understood as its capability to be used in the MD2 approach to automatically generate semantic annotations within the didactic material development

  13. First-Principles Models of Properties of LMR-NMC Materials

    Broader source: Energy.gov (indexed) [DOE]

    First-Principles Models of Properties of LMR-NMC Materials Project Id: ES193 R. Benedek, H. Iddir DOE Vehicle Technologies Program Annual Merit Review Arlington, VA May 13 - 17,...

  14. Material characterization of high-voltage lithium-ion battery models for crashworthiness analysis

    E-Print Network [OSTI]

    Meier, Joseph D. (Joseph David)

    2013-01-01T23:59:59.000Z

    A three-phased study of the material properties and post-impact behavior of prismatic pouch lithium-ion battery cells was conducted to refine computational finite element models and explore the mechanisms of thermal runaway ...

  15. Modeling a solar energy collector with an integrated phase-change material

    E-Print Network [OSTI]

    Guerra, Alexander Adrian

    2009-01-01T23:59:59.000Z

    In this thesis, a finite-element computer model was created to simulate a solar air heater with an integrated-phase change material. The commercially available finite element package ADINA-Fluid was used to generate the ...

  16. Vehicle Technologies Office Merit Review 2014: Validation of Material Models for Automotive Carbon Fiber Composite Structures

    Broader source: Energy.gov [DOE]

    Presentation given by General Motors at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about validation of material models...

  17. Development of Apple Workgroup Cluster and Parallel Computing for Phase Field Model of Magnetic Materials 

    E-Print Network [OSTI]

    Huang, Yongxin

    2010-01-16T23:59:59.000Z

    using MPI. The results show the cluster system can simultaneously support up to 32 processes for MPI program with high performance of interprocess communication. The parallel computations of phase field model of magnetic materials implemented by a MPI...

  18. International Conference "Computational Modeling and Simulation of Materials" Sicily 2004

    E-Print Network [OSTI]

    Webb, Roger P.

    how the deformation of a silicon surface caused by a high energy C60 impact can eject a large cages. But also the use of C60 ions in secondary mass spectrometry (SIMS) as a probing beam is showing in collaboration with the University of Karlsruhe, the simulation models have been verified for both low energy

  19. Page 1 of 9 MASTER OF PHILOSOPHY, Modelling of Materials

    E-Print Network [OSTI]

    Cambridge, University of

    computer models are those in which the future state of the system is completely determined by the initial of random numbers, and thus the future state of the system is inherently unpredictable given the same a phase transition (e.g. for studying pure systems); cooling curves (changes in cooling rates at a phase

  20. A prototype homogenization model for acoustics of granular materials

    E-Print Network [OSTI]

    Panchenko, Alexander

    initially by the Coulomb's law with normal compliance. These inequality-type conditions are approximatedÃ?cult to specify the required constitutive laws for the extra variables. A notable representative to model slow Article submitted to Royal Society T E X Paper #12; 2 Gilbert, Panchenko and Xie deformations

  1. The development of a flood routing model for the flow analyses of mine tailings materials

    E-Print Network [OSTI]

    Rokohl, Don Richard

    1984-01-01T23:59:59.000Z

    THE DEVELOPMENT OF A FLOOD ROUTING MODEL FOR THE FLOW ANALYSES OF MINE TAILINGS MATERIALS A Thesis DON RICHARD ROKOHL Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1984 Major Subject: Civil Engineering THE DEVELOPMENT OF A PLOOD ROUTING MODEL POR THE FLOW ANALTSES OF MINE TAILINGS MATERIALS A Thesis by DON RICHARD ROKOHL Approved as to style and content by: Harry M. Coyle (Co...

  2. A hierarchical framework for the multiscale modeling of microstructure evolution in heterogeneous materials.

    SciTech Connect (OSTI)

    Luscher, Darby J.

    2010-04-01T23:59:59.000Z

    All materials are heterogeneous at various scales of observation. The influence of material heterogeneity on nonuniform response and microstructure evolution can have profound impact on continuum thermomechanical response at macroscopic “engineering” scales. In many cases, it is necessary to treat this behavior as a multiscale process thus integrating the physical understanding of material behavior at various physical (length and time) scales in order to more accurately predict the thermomechanical response of materials as their microstructure evolves. The intent of the dissertation is to provide a formal framework for multiscale hierarchical homogenization to be used in developing constitutive models.

  3. Stress and Failure Analysis of Rapidly Rotating Asteroid (29075) 1950 DA

    E-Print Network [OSTI]

    Hirabayashi, Masatoshi

    2014-01-01T23:59:59.000Z

    Rozitis et al. recently reported that near-Earth asteroid (29075) 1950 DA, whose bulk density ranges from 1.0 g/cm3 to 2.4 g/cm3, is a rubble pile and requires a cohesive strength of at least 44 Pa to 74 Pa to keep from failing due to its fast spin period. Since their technique for giving failure conditions required the averaged stress over the whole volume, it discarded information about the asteroid's failure mode and internal stress condition. This paper develops a finite element model and revisits the stress and failure analysis of 1950 DA. For the modeling, we do not consider material-hardening and softening. Under the assumption of an associated flow rule and uniform material distribution, we identify the deformation process of 1950 DA when its constant cohesion reaches the lowest value that keeps its current shape. The results show that to avoid structural failure the internal core requires a cohesive strength of at least 75 Pa - 85 Pa. It suggests that for the failure mode of this body, the internal c...

  4. Creep failure of a reactor pressure vessel lower head under severe accident conditions

    SciTech Connect (OSTI)

    Pilch, M.M.; Ludwigsen, J.S.; Chu, T.Y. [Sandia National Labs., Albuquerque, NM (United States); Rashid, Y.R. [Anatech, San Diego, CA (United States)

    1998-08-01T23:59:59.000Z

    A severe accident in a nuclear power plant could result in the relocation of large quantities of molten core material onto the lower head of he reactor pressure vessel (RPV). In the absence of inherent cooling mechanisms, failure of the RPV ultimately becomes possible under the combined effects of system pressure and the thermal heat-up of the lower head. Sandia National Laboratories has performed seven experiments at 1:5th scale simulating creep failure of a RPV lower head. This paper describes a modeling program that complements the experimental program. Analyses have been performed using the general-purpose finite-element code ABAQUS-5.6. In order to make ABAQUS solve the specific problem at hand, a material constitutive model that utilizes temperature dependent properties has been developed and attached to ABAQUS-executable through its UMAT utility. Analyses of the LHF-1 experiment predict instability-type failure. Predicted strains are delayed relative to the observed strain histories. Parametric variations on either the yield stress, creep rate, or both (within the range of material property data) can bring predictions into agreement with experiment. The analysis indicates that it is necessary to conduct material property tests on the actual material used in the experimental program. The constitutive model employed in the present analyses is the subject of a separate publication.

  5. Application of micromechanical models of ductile fracture initiation to reactor pressure vessel materials

    SciTech Connect (OSTI)

    Chaouadi, R.; Walle, E. van; Fabry, A.; Velde, J. van de [SCK-CEN, Mol (Belgium); Meester, P. de [KUL, Heverlee (Belgium). Metals and Materials Science Dept.

    1996-12-31T23:59:59.000Z

    The aim of the current study is the application of local micromechanical models to predict crack initiation in ductile materials. Two reactor pressure vessel materials have been selected for this study: JRQ IAEA monitor base metal (A533B Cl.1) and Doel-IV weld material. Charpy impact tests have been performed in both un-irradiated and irradiated conditions. In addition to standard tensile tests, notched tensile specimens have been tested. The upper shelf energy of the weld material remains almost un-affected by irradiation, whereas a decrease of 20% is detected for the base metal. Accordingly, the tensile properties of the weld material do not reveal a clear irradiation effect on the yield and ultimate stresses, this in contrast to the base material flow properties. The tensile tests have been analyzed in terms of micromechanical models. A good correlation is found between the standard tests and the micromechanical models, that are able to predict the ductile damage evolution in these materials. Additional information on the ductility behavior of these materials is revealed by this micromechanical analysis.

  6. SYNTHETIC SLING FAILURE - EVALUATIONS & RECOMMENDATIONS

    SciTech Connect (OSTI)

    MACKEY TC; HENDERSON CS

    2009-10-26T23:59:59.000Z

    The information and evaluations provided in this report were compiled to address the recurring problem of synthetic sling failure. As safety is the number one priority in all work aspects, a solution must be devised to prevent accidents from occurring. A total of thirteen cases regarding synthetic sling failure were evaluated in order to determine their causes, effects, and preventative measures. From the collected data, it was found that all cases in which the synthetic sling contacted the edge of its load resulted in sling failure. It is required that adequate synthetic sling protection devices be used to protect slings in any lift where the sling comes in direct contact with the edge or corner of its load. However, there are no consensus codes or standards stating the type, material, or purpose of the type of protective device used to protect the sling from being cut. Numerous industry standards and codes provide vague descriptions on how to protect synthetic slings. Without a clear, concise statement of how to protect synthetic slings, it is common for inadequate materials and sling protection devices to be used in an attempt to meet the intent of these requirements. The use of an inadequate sling protection device is the main cause of synthetic sling failure in all researched cases. Commercial sling protection devices come in many shapes and sizes, and have a variety of names, as well as advertised uses. 'Abrasion pads' and 'wear protectors' are two different names for products with the same intended purpose. There is no distinguishable way to determine the extent of sling protection which these devices will provide, or what specific scenarios they are made for. This creates room for error in a field where error is unacceptable. This report provides a recommended action for hoisting and rigging activities which require synthetic slings to contact a load, as well as recommended changes to industry standards which will benefit overall industry safety.

  7. Corrosion failures of austenitic stainless steel piping

    SciTech Connect (OSTI)

    Louthan, M.R. Jr.

    1993-10-01T23:59:59.000Z

    The safe and efficient operation of many chemical/industrial systems requires the continued integrity of the process piping; this is achieved through a complex series of interactions influenced by design, fabrication, construction, operation, inspection and lay-up requirements. Potential material-enviroment interactions are frequently, if evaluated at all, relegated to secondary considerations. This tendency virtually assures corrosion induced degradation of the process piping systems. Pitting, crevice attack, stress cracking, microbiologically influenced corrosion, intergranular attack and corrosion fatigue have caused leaks, cracks, failures and shutdown of numerous process systems. This paper uses the lessons learned from failure analysis to emphasize the importance of an integrated material program to system success. The necessity of continuing evaluation if also emphasized through examples of failures which were associated with materials-environment interactions caused by slight alterations of processes and/or systems.

  8. This paper focuses on solving the failure detection and isolation (FDI) problem by developing a model-based

    E-Print Network [OSTI]

    Taylor, James H.

    to a jacketed continuous stirred tank reactor (JCSTR). 1. Introduction The continuous and growing advances is exposed. In section 4 a novel calculation of the transformation matrix is proposed to improve isolation. In section 6, an example using a jacketed continuous stirred tank reactor (JCSTR) model is used to illustrate

  9. MODELING OF TRIPLE JUNCTION A-SI SOLAR CELLS USING ASA: ANALYSIS OF DEVICE PERFORMANCE UNDER VARIOUS FAILURE SCENARIOS

    E-Print Network [OSTI]

    Deng, Xunming

    have experienced a significant increase in the recent years. Solar panels with triple- junction found. To assist the optimization of solar cell fabrication and cost-effective industrial photovoltaicMODELING OF TRIPLE JUNCTION A-SI SOLAR CELLS USING ASA: ANALYSIS OF DEVICE PERFORMANCE UNDER

  10. EDDY CURRENT TESTING OF FERROMAGNETIC MATERIALS: MODELLING OF MULTIPLE FLAWS IN A

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    EDDY CURRENT TESTING OF FERROMAGNETIC MATERIALS: MODELLING OF MULTIPLE FLAWS IN A PLANAR STRATIFIED ­ Université Paris Sud 11), 3, rue Joliot-Curie, 91192 Gif-sur- Yvette, France ! "#$%&'(%! Eddy current testing. Lambert, H. Voillaume and N. Dominguez, "A 3D model for eddy current inspection in aeronautics

  11. On Some Models in Linear Thermo-Elasticity with Rational Material Laws

    E-Print Network [OSTI]

    Santwana Mukhopadhyay; Rainer Picard; Sascha Trostorff; Marcus Waurick

    2014-09-03T23:59:59.000Z

    We shall consider some common models in linear thermo-elasticity within a common structural framework. Due to the flexibility of the structural perspective we will obtain well-posedness results for a large class of generalized models allowing for more general material properties such as anisotropies, inhomogeneities, etc.

  12. Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Direct Modeling of Material Deposit and Identification of Energy Transfer in Gas Metal Arc Welding sources for finite element simulation of gas metal arc welding (GMAW). Design for the modeling of metal deposition results in a direct calculation of the formation of the weld bead, without any

  13. Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding M. Grujicic yet a fairly comprehensive overview of the friction stir welding (FSW) process is provided-element procedure developed in our prior study. Particular attention is given to proper modeling of the welding work

  14. NONLINEAR ANALYSIS OF RUBBER-BASED POLYMERIC MATERIALS WITH THERMAL RELAXATION MODELS

    E-Print Network [OSTI]

    Melnik, Roderick

    NONLINEAR ANALYSIS OF RUBBER-BASED POLYMERIC MATERIALS WITH THERMAL RELAXATION MODELS R. V. N Queensland, Australia Using mathematical modeling and computer simulation, nonlinear dynamics of rubber in the thermomechanical system. 1. INTRODUCTION The effect of thermal relaxation in rubber-based polymers is one

  15. Catalysinganenergyrevolution Nuclear Failures

    E-Print Network [OSTI]

    Laughlin, Robert B.

    extraction, fuel manufacture and management of spent fuel and waste. Currently, CEA is a large FrenchCatalysinganenergyrevolution France's Nuclear Failures The great illusion of nuclear energy greenpeace.org #12;Contents 2 Greenpeace International France's Nuclear Failures The French nuclear industry

  16. Modeling of diffusive mass transport in micropores in cement based materials

    SciTech Connect (OSTI)

    Yamaguchi, Tetsuji, E-mail: yamaguchi.tetsuji@jaea.go.j [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan); Negishi, Kumi [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan); Taiheiyo Consultant Company Limited, 2-4-2, Osaku, Sakura, Chiba 285-8655 (Japan); Hoshino, Seiichi; Tanaka, Tadao [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan)

    2009-12-15T23:59:59.000Z

    In order to predict long-term leaching behavior of cement constituents for safety assessments of radioactive waste disposal, we modeled diffusive mass transport in micropores in cement based materials. Based on available knowledge on the pore structure, we developed a transport porosity model that enables us to estimate effective porosity available for diffusion (transport porosity) in cement based materials. We microscopically examined the pore structure of hardened cement pastes to partially verify the model. Effective diffusivities of tritiated water in hardened cement pastes were also obtained experimentally, and were shown to be proportional to the estimated transport porosity.

  17. Data collection handbook to support modeling the impacts of radioactive material in soil

    SciTech Connect (OSTI)

    Yu, C.; Cheng, J.J.; Jones, L.G.; Wang, Y.Y.; Faillace, E. [Argonne National Lab., IL (United States). Environmental Assessment and Information Sciences Div.; Loureiro, C. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Engenharia; Chia, Y.P. [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Geology

    1993-04-01T23:59:59.000Z

    A pathway analysis computer code called RESRAD has been developed for implementing US Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), and material-related (soil, concrete) parameters are used in the RESRAD code. This handbook discusses parameter definitions, typical ranges, variations, measurement methodologies, and input screen locations. Although this handbook was developed primarily to support the application of RESRAD, the discussions and values are valid for other model applications.

  18. Toward Multi-scale Modeling and simulation of conduction in heterogeneous materials.

    SciTech Connect (OSTI)

    Lechman, Jeremy B.; Battaile, Corbett Chandler.; Bolintineanu, Dan; Cooper, Marcia A.; Erikson, William W.; Foiles, Stephen M.; Kay, Jeffrey J [Sandia National Laboratories, Livermore, CA; Phinney, Leslie M.; Piekos, Edward S.; Specht, Paul Elliott; Wixom, Ryan R.; Yarrington, Cole

    2015-01-01T23:59:59.000Z

    This report summarizes a project in which the authors sought to develop and deploy: (i) experimental techniques to elucidate the complex, multiscale nature of thermal transport in particle-based materials; and (ii) modeling approaches to address current challenges in predicting performace variability of materials (e.g., identifying and characterizing physical- chemical processes and their couplings across multiple length and time scales, modeling infor- mation transfer between scales, and statically and dynamically resolving material structure and its evolution during manufacturing and device performance). Experimentally, several capabilities were sucessfully advanced. As discussed in Chapter 2 a flash diffusivity capabil- ity for measuring homogeneous thermal conductivity of pyrotechnic powders (and beyond) was advanced; leading to enhanced characterization of pyrotechnic materials and properties impacting component development. Chapter 4 describes sucess for the first time, although preliminary, in resolving thermal fields at speeds and spatial scales relevant to energetic components. Chapter 7 summarizes the first ever (as far as the authors know) application of TDTR to actual pyrotechnic materials. This is the first attempt to actually characterize these materials at the interfacial scale. On the modeling side, new capabilities in image processing of experimental microstructures and direct numerical simulation on complicated structures were advanced (see Chapters 3 and 5). In addition, modeling work described in Chapter 8 led to improved prediction of interface thermal conductance from first principles calculations. Toward the second point, for a model system of packed particles, significant headway was made in implementing numerical algorithms and collecting data to justify the approach in terms of highlighting the phenomena at play and pointing the way forward in de- veloping and informing the kind of modeling approach oringinally envisioned (see Chapter 6). In both cases much more remains to be accomplished.

  19. Coping with dependent failures in distributed systems

    E-Print Network [OSTI]

    Junqueira, Flavio

    2006-01-01T23:59:59.000Z

    Mosleh. Dependent failure analysis. Reliability engineeringIntrospective failure analysis: Avoiding correlated failuresThe analysis in [Kum91], however, assumes IID failures. The

  20. Models for mean bonding length, melting point and lattice thermal expansion of nanoparticle materials

    SciTech Connect (OSTI)

    Omar, M.S., E-mail: dr_m_s_omar@yahoo.com [Department of Physics, College of Science, University of Salahaddin-Erbil, Arbil, Kurdistan (Iraq)

    2012-11-15T23:59:59.000Z

    Graphical abstract: Three models are derived to explain the nanoparticles size dependence of mean bonding length, melting temperature and lattice thermal expansion applied on Sn, Si and Au. The following figures are shown as an example for Sn nanoparticles indicates hilly applicable models for nanoparticles radius larger than 3 nm. Highlights: ? A model for a size dependent mean bonding length is derived. ? The size dependent melting point of nanoparticles is modified. ? The bulk model for lattice thermal expansion is successfully used on nanoparticles. -- Abstract: A model, based on the ratio number of surface atoms to that of its internal, is derived to calculate the size dependence of lattice volume of nanoscaled materials. The model is applied to Si, Sn and Au nanoparticles. For Si, that the lattice volume is increases from 20 ?{sup 3} for bulk to 57 ?{sup 3} for a 2 nm size nanocrystals. A model, for calculating melting point of nanoscaled materials, is modified by considering the effect of lattice volume. A good approach of calculating size-dependent melting point begins from the bulk state down to about 2 nm diameter nanoparticle. Both values of lattice volume and melting point obtained for nanosized materials are used to calculate lattice thermal expansion by using a formula applicable for tetrahedral semiconductors. Results for Si, change from 3.7 × 10{sup ?6} K{sup ?1} for a bulk crystal down to a minimum value of 0.1 × 10{sup ?6} K{sup ?1} for a 6 nm diameter nanoparticle.

  1. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 10 (2002) 341357 PII: S0965-0393(02)35520-7

    E-Print Network [OSTI]

    Melnik, Roderick

    2002-01-01T23:59:59.000Z

    INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING and heat transfer in processing polymeric materials with applications to biochemical engineering Roderick V reaction kinetics and heat transfer in polymeric materials. In this paper we consider mathematical models

  2. A 3D Orthotropic Strain-Rate Dependent Elastic Damage Material Model.

    SciTech Connect (OSTI)

    English, Shawn Allen

    2014-09-01T23:59:59.000Z

    A three dimensional orthotropic elastic constitutive model with continuum damage and cohesive based fracture is implemented for a general polymer matrix composite lamina. The formulation assumes the possibility of distributed (continuum) damage followed b y localized damage. The current damage activation functions are simply partially interactive quadratic strain criteria . However, the code structure allows for changes in the functions without extraordinary effort. The material model formulation, implementation, characterization and use cases are presented.

  3. FINITE ELEMENT MODEL-BASED STRUCTURAL HEALTH MONITORING (SHM) SYSTEMS FOR COMPOSITE MATERIAL UNDER

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    FINITE ELEMENT MODEL-BASED STRUCTURAL HEALTH MONITORING (SHM) SYSTEMS FOR COMPOSITE MATERIAL UNDER). To design a Structural Health Monitoring (SHM) system, it is important to understand phenomenologically Workshop on Structural Health Monitoring July 8-11, 2014. La Cité, Nantes, France Copyright © Inria (2014

  4. Stochastic Simulation Model for the 3D Morphology of Composite Materials in Li-Ion Batteries

    E-Print Network [OSTI]

    Schmidt, Volker

    Stochastic Simulation Model for the 3D Morphology of Composite Materials in Li-Ion Batteries Ralf August 30, 2010 Abstract Battery technology plays an important role in energy storage. In particular, lithium­ ion (Li-ion) batteries are of great interest, because of their high capacity, long cycle life

  5. On modeling shape memory polymers as thermoelastic two-phase composite materials

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    On modeling shape memory polymers as thermoelastic two-phase composite materials P. Gilormini, J the experimentally observed mechanical behavior of some shape memory polymers. It considers a purely thermoelastic. Mecanique xxx (2011). Key words: Shape memory ; Polymers Mots-clés : Mémoire de forme ; Polymères Email

  6. Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials A. Karrech a,, A. Seibi thrust is the introduc- tion of the "Chicago" law in a continuum approach to account for the ratcheting or jointly with the ratcheting effect. Non-associated plasticity is adopted since the paper mainly targets

  7. Modelling the Zn emissions from roofing materials at Crteil city scale -Defining a methodology

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modelling the Zn emissions from roofing materials at Créteil city scale - Defining a methodology@cereve.enpc.fr) Abstract Today, urban runoff is considered as an important source of environment pollution. Roofing. An accurate evaluation of contaminant flows from roofs is thus required at the city scale. This paper aims

  8. Supporting Materials for "Spin models inferred from patient-derived viral sequence

    E-Print Network [OSTI]

    Ferguson, Andrew

    Supporting Materials for "Spin models inferred from patient-derived viral sequence data faithfullyN be an arbitrary sequence1 in an equilibrium ensemble of M sequences sampled according to Hint[s] using the Metropolis Monte Carlo (MC) algorithm [1]. This ensemble is com- prised of sequences from six independent

  9. 02/25/2014 27th CSP Workshop 1 First Principles Modeling of Electrolye Materials

    E-Print Network [OSTI]

    Holzwarth, Natalie

    02/25/2014 27th CSP Workshop 1 First Principles Modeling of Electrolye Materials in All Abdessadek Lachgar. #12;02/25/2014 27th CSP Workshop 2 Outline What is meant by "first principles/electrode interfaces Remaining challenges #12;02/25/2014 27th CSP Workshop 3 What is meant by "first principles

  10. Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing,

    E-Print Network [OSTI]

    Optimization J. Vernon Cole and Ashok Gidwani CFDRC Prepared for: DOE Hydrogen Fuel Cell Kickoff MeetingWater Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing, and Design fuel cell design and operation; Demonstrate improvements in water management resulting in improved

  11. FAILURE PREDICTION AND STRESS ANALYSIS OF MICROCUTTING TOOLS

    E-Print Network [OSTI]

    Chittipolu, Sujeev

    2010-07-14T23:59:59.000Z

    -based products are limited because silicon is brittle. Products can be made from other engineering materials and need to be machined in microscale. This research deals with predicting microtool failure by studying spindle runout and tool deflection effects...

  12. JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES Vol. 3, No. 7, 2008

    E-Print Network [OSTI]

    Wadley, Haydn

    materials, composites, microbuckling, honeycomb, carbon fiber, carbon fibre. 1315 #12;1316 BENJAMIN P. WADLEY Carbon fibre epoxy matrix composite honeycombs have been fabricated by slotting, assembling modes were elastic buckling or shear failure of the composite sheet material. Analytical models

  13. Workshop on Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials

    SciTech Connect (OSTI)

    Giles, GE

    2005-02-03T23:59:59.000Z

    The purpose of this Workshop on ''Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials'' was to solicit functional requirements for tools that help Incident Managers plan for and deal with the consequences of industrial or terrorist releases of materials into the nation's waterways and public water utilities. Twenty representatives attended and several made presentations. Several hours of discussions elicited a set of requirements. These requirements were summarized in a form for the attendees to vote on their highest priority requirements. These votes were used to determine the prioritized requirements that are reported in this paper and can be used to direct future developments.

  14. Analysis of Dam Failure in the Saluda River February 8, 2005

    E-Print Network [OSTI]

    Morrow, James A.

    Analysis of Dam Failure in the Saluda River Valley February 8, 2005 Abstract We identify and model two possible failure modes for the Saluda Dam: gradual failure due to an enlarging breach and sudden catas- trophic failure due to liqui#12;cation of the dam. For the #12;rst case we de- scribe the breach

  15. ensl-00156842,version1-22Jun2007 Sub-critical statistics in rupture of fibrous materials : experiments and model.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ensl-00156842,version1-22Jun2007 Sub-critical statistics in rupture of fibrous materials for sub-critical point statistics. We stress that the material heterogene- ity appears in the model only 24, 2007) We study experimentally the slow growth of a single crack in a fibrous material and observe

  16. JOM, 2013, Vol. 65, No. 2, pp. TBD. Modeling and simulation in composite materials integration from nanostructure to component level

    E-Print Network [OSTI]

    Gupta, Nikhil

    . In the long term, these resources are expected to enable development of new materials for critical application1 JOM, 2013, Vol. 65, No. 2, pp. TBD. Modeling and simulation in composite materials ­ integration from nanostructure to component level design Nikhil Gupta Composite Materials and Mechanics Laboratory

  17. Materials in Extreme Dynamic Environments Georgia Tech has a unique combination of experimental facilities and modeling and

    E-Print Network [OSTI]

    Li, Mo

    response of materials at various critical length and time scales emphasizes both highMaterials in Extreme Dynamic Environments Georgia Tech has a unique combination of experimental facilities and modeling and simulation capabilities to explore the behavior of materials subjected to high

  18. INTERDICTION MODELING FOR SMUGGLED NUCLEAR MATERIAL Nedialko B. Dimitrov, Marc A. Gonzalez, Dennis P. Michalopoulos, David P. Morton,

    E-Print Network [OSTI]

    Morton, David

    (DOE) seeks to reduce the risk of illicit trafficking of nuclear material through international and smuggling of nuclear material and (ii) to detect and therefore prevent actual smuggling attemptsINTERDICTION MODELING FOR SMUGGLED NUCLEAR MATERIAL Nedialko B. Dimitrov, Marc A. Gonzalez, Dennis

  19. ALE3D Model Predictions and Materials Characterization for the Cookoff Response of PBXN-109

    SciTech Connect (OSTI)

    McClelland, M A; Maienschein, J L; Nichols, A L; Wardell, J F; Atwood, A I; Curran, P O

    2002-03-19T23:59:59.000Z

    ALE3D simulations are presented for the thermal explosion of PBXN-109 (RDX, AI, HTPB, DOA) in support of an effort by the U. S. Navy and Department of Energy (DOE) to validate computational models. The U.S. Navy is performing benchmark tests for the slow cookoff of PBXN-109 in a sealed tube. Candidate models are being tested using the ALE3D code, which can simulate the coupled thermal, mechanical, and chemical behavior during heating, ignition, and explosion. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. A void model is employed to represent the air in gaps. ALE3D model 'parameters are specified using measurements of thermal and mechanical properties including thermal expansion, heat capacity, shear modulus, and bulk modulus. A standard three-step chemical kinetics model is used during the thermal ramp, and a pressure-dependent burn front model is employed during the rapid expansion. Parameters for the three-step kinetics model are specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate of pristine and thermally damaged material are employed to determine parameters in the burn front model. Results are given for calculations in which heating, ignition, and explosion are modeled in a single simulation. We compare model results to measurements for the cookoff temperature and tube wall strain.

  20. Journal of Multiscale Modelling Vol. 1, No. 1 (2009) 2155

    E-Print Network [OSTI]

    Ghosh, Somnath

    2009-01-01T23:59:59.000Z

    . Modeling structure­material interaction in damage and failure analysis requires consideration of large is detailed micromechanical analysis of particle fragmentation and matrix crack- ing of heterogeneous microstructures. A locally enriched VCFEM or LE-VCFEM is developed to incorporate ductile failure through matrix

  1. Numerical upscaling for the eddy-current model with stochastic magnetic materials

    SciTech Connect (OSTI)

    Eberhard, Jens P. [Computer Simulation Technology, Bad Nauheimer Strasse, 19, D-64289 Darmstadt (Germany)], E-mail: jens.eberhard@cst.com; Popovic, Dan [Simulation in Technology, University of Heidelberg, Im Neuenheimer Feld 368, D-69120 Heidelberg (Germany)], E-mail: dan.popovic@stud.uni-heidelberg.de; Wittum, Gabriel [Simulation in Technology, University of Heidelberg, Im Neuenheimer Feld 368, D-69120 Heidelberg (Germany)], E-mail: wittum@uni-hd.de

    2008-04-01T23:59:59.000Z

    This paper deals with the upscaling of the time-harmonic Maxwell equations for heterogeneous media. We analyze the eddy-current approximation of Maxwell's equations to describe the electric field for heterogeneous, isotropic magnetic materials. The magnetic permeability of the materials is assumed to have random heterogeneities described by a Gaussian random field. We apply the so-called Coarse Graining method to develop a numerical upscaling of the eddy-current model. The upscaling uses filtering and averaging procedures in Fourier space which results in a formulation of the eddy-current model on coarser resolution scales where the influence of sub-scale fluctuations is modeled by effective scale- and space-dependent reluctivity tensors. The effective reluctivity tensors can be obtained by solving local partial differential equations which contain a Laplacian as well as a curl-curl operator. We present a computational method how the equation of the combined operators can be discretized and solved numerically using an extended variational formulation compared to standard discretizations. We compare the results of the numerical upscaling of the eddy-current model with theoretical results of Eberhard [J.P. Eberhard, Upscaling for the time-harmonic Maxwell equations with heterogeneous magnetic materials, Physical Review E 72 (3), (2005)] and obtain a very good agreement.

  2. A second gradient theoretical framework for hierarchical multiscale modeling of materials

    SciTech Connect (OSTI)

    Luscher, Darby J [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Mc Dowell, David L [GEORGIA TECH

    2009-01-01T23:59:59.000Z

    A theoretical framework for the hierarchical multiscale modeling of inelastic response of heterogeneous materials has been presented. Within this multiscale framework, the second gradient is used as a non local kinematic link between the response of a material point at the coarse scale and the response of a neighborhood of material points at the fine scale. Kinematic consistency between these scales results in specific requirements for constraints on the fluctuation field. The wryness tensor serves as a second-order measure of strain. The nature of the second-order strain induces anti-symmetry in the first order stress at the coarse scale. The multiscale ISV constitutive theory is couched in the coarse scale intermediate configuration, from which an important new concept in scale transitions emerges, namely scale invariance of dissipation. Finally, a strategy for developing meaningful kinematic ISVs and the proper free energy functions and evolution kinetics is presented.

  3. FRAPCON-3: Modifications to fuel rod material properties and performance models for high-burnup application

    SciTech Connect (OSTI)

    Lanning, D.D.; Beyer, C.E.; Painter, C.L.

    1997-12-01T23:59:59.000Z

    This volume describes the fuel rod material and performance models that were updated for the FRAPCON-3 steady-state fuel rod performance code. The property and performance models were changed to account for behavior at extended burnup levels up to 65 Gwd/MTU. The property and performance models updated were the fission gas release, fuel thermal conductivity, fuel swelling, fuel relocation, radial power distribution, solid-solid contact gap conductance, cladding corrosion and hydriding, cladding mechanical properties, and cladding axial growth. Each updated property and model was compared to well characterized data up to high burnup levels. The installation of these properties and models in the FRAPCON-3 code along with input instructions are provided in Volume 2 of this report and Volume 3 provides a code assessment based on comparison to integral performance data. The updated FRAPCON-3 code is intended to replace the earlier codes FRAPCON-2 and GAPCON-THERMAL-2. 94 refs., 61 figs., 9 tabs.

  4. Examination of the damage and failure response of tantalum and copper under varied shock loading conditions

    SciTech Connect (OSTI)

    Bronkhorst, Curt A [Los Alamos National Laboratory; Dennis - Koller, Darcie [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Gray Ill, George T [Los Alamos National Laboratory; Bourne, Neil [AWE-ALDERMASTON

    2010-12-16T23:59:59.000Z

    A number of plate impact experiments have been conducted on high purity polycrystalline tantalum and copper samples using graded flyer plate configurations to alter the loading profile. These experiments are designed in a way so that a broad range of damage regimes are probed. The results show that the nucleation of damage primarily occurs at the grain boundaries of the materials. This affords us the opportunity to propose a porosity damage nucleation criterion which begins to account for the length scales of the microstructure (grain size distribution) and the mechanical response of the grain boundary regions (failure stress distribution). This is done in the context of a G-T-N type model for the ductile damage and failure response of both the materials examined. The role of micro-inertial effects on the porosity growth process is also considered.

  5. A Free Energy Model for Piezoceramic Materials Ralph C. Smith , Stefan Seelecke y and Zoubeida Ounaies z

    E-Print Network [OSTI]

    A Free Energy Model for Piezoceramic Materials Ralph C. Smith #3; , Stefan Seelecke y and Zoubeida the development of a free energy model for quantifying the hysteresis and constitutive nonlinearities inherent to piezoceramic materials. In the #12;rst step of the development, free energy relations for a single crystal

  6. Modeling the interaction of high power ion or electron beams with solid target materials

    SciTech Connect (OSTI)

    Hassanein, A.M.

    1983-11-01T23:59:59.000Z

    Intense energy deposition on first wall materials and other components as a result of plasma disruptions in magnetic fusion devices are expected to cause melting and vaporization of these materials. The exact amount of vaporization losses and melt layer thickness are very important to fusion reactor design and lifetime. Experiments using ion or electron beams to simulate the disruption effects have different environments than the actual disruption conditions in fusion reactors. A model has been developed to accurately simulate the beam-target interactions so that the results from such experiments can be meaningful and useful to reactor design. This model includes a two dimensional solution of the heat conduction equation with moving boundaries. It is found that the vaporization and melting of the sample strongly depends on the characteristics of the beam spatial distribution, beam diameter, and on the power-time variation of the beam.

  7. alpha-mode containment failure: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Summary: of stainless steel container materials is a potential problem for long-term radioactive waste storage-to-failure of relevant stainless steels in the annealed...

  8. Common-Cause Failure Analysis in Event Assessment

    SciTech Connect (OSTI)

    Dana L. Kelly; Dale M. Rasmuson

    2008-09-01T23:59:59.000Z

    This paper describes the approach taken by the U. S. Nuclear Regulatory Commission to the treatment of common-cause failure in probabilistic risk assessment of operational events. The approach is based upon the Basic Parameter Model for common-cause failure, and examples are illustrated using the alpha-factor parameterization, the approach adopted by the NRC in their Standardized Plant Analysis Risk (SPAR) models. The cases of a failed component (with and without shared common-cause failure potential) and a component being unavailable due to preventive maintenance or testing are addressed. The treatment of two related failure modes (e.g., failure to start and failure to run) is a new feature of this paper. These methods are being applied by the NRC in assessing the risk significance of operational events for the Significance Determination Process (SDP) and the Accident Sequence Precursor (ASP) program.

  9. Two- and Three-Dimensional Microstructural Modeling of Asphalt Particulate Composite Materials using a Unified Viscoelastic-Viscoplastic-Viscodamage Constitutive Model

    E-Print Network [OSTI]

    You, Taesun

    2013-08-13T23:59:59.000Z

    The main objective of this study is to develop and validate a framework for microstructural modeling of asphalt composite materials using a coupled thermo-viscoelastic, thermo-viscoplastic, and thermo-viscodamage constitutive model. In addition...

  10. Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material

    SciTech Connect (OSTI)

    Springer, H K

    2008-06-26T23:59:59.000Z

    The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accounted for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed and executed for the purpose of validating closely-coupled 3D MSS. While the spall strength is nearly independent of specimen thickness, the fragment morphology varies widely. Detailed MSS demonstrate that the interactions between the tensile release waves are altered by specimen thickness and that these interactions are primarily responsible for fragment formation. MSS also provided insights on the regional amplification of damage, which enables the development of predictive void evolution models.

  11. Electrical overstress failure in silicon solar cells

    SciTech Connect (OSTI)

    Pease, R.L.; Barnum, J.R.; van Lint, V.A.J.; Vulliet, W.V.; Wrobel, T.F.

    1982-11-01T23:59:59.000Z

    A solar-cell electrical-overstress-failure model and the results of experimental measurements of threshold pulsed failure currents on four types of silicon solar cells are presented. The transient EMP field surrounding a lightning stroke has been identified as a potential threat to a photovoltaic array, yet failure analysis of solar cells in a pulsed environment had not previously been reported. Failure in the low-resistivity concentrator cells at pulse widths between 1 ..mu..s and 1 ms occurred initially in the junction. Finger damage in the form of silver melting occurs at currents only slightly greater than that required for junction damage. The result of reverse-bias transient-overstress tests on high-resistivity (10 ..cap omega..cm) cells demonstrated that the predominant failure mode was due to edge currents. These flat-plate cells failed at currents of only 4 to 20 A, which is one or two orders of magnitude below the model predictions. It thus appears that high-resistivity flat-plate cells are quite vulnerable to electrical overstress which could be produced by a variety of mechanisms.

  12. Theory, modeling and instrumentation for materials by design: Proceedings of workshop

    SciTech Connect (OSTI)

    Allen, R.E.; Cocke, D.L.; Eberhardt, J.J.; Wilson, A. (eds.)

    1984-01-01T23:59:59.000Z

    The following topics are contained in this volume: how can materials theory benefit from supercomputers and vice-versa; the materials of xerography; relationship between ab initio and semiempirical theories of electronic structure and renormalization group and the statistical mechanics of polymer systems; ab initio calculations of materials properties; metals in intimate contact; lateral interaction in adsorption: revelations from phase transitions; quantum model of thermal desorption and laser stimulated desorption; extended fine structure in appearance potential spectroscopy as a probe of solid surfaces; structural aspects of band offsets at heterojunction interfaces; multiconfigurational Green's function approach to quantum chemistry; wavefunctions and charge densities for defects in solids: a success for semiempirical theory; empirical methods for predicting the phase diagrams of intermetallic alloys; theoretical considerations regarding impurities in silicon and the chemisorption of simple molecules on Ni; improved Kohn-Sham exchange potential; structural stability calculations for films and crystals; semiempirical molecular orbital modeling of catalytic reactions including promoter effects; theoretical studies of chemical reactions: hydrolysis of formaldehyde; electronic structure calculations for low coverage adlayers; present status of the many-body problem; atomic scattering as a probe of physical adsorption; and, discussion of theoretical techniques in quantum chemistry and solid state physics.

  13. Molecular Modeling of Self-assembling Hybrid Materials (PhD Thesis)

    E-Print Network [OSTI]

    Alessandro Patti

    2010-06-04T23:59:59.000Z

    Lattice Monte Carlo simulations are used to study the phase behavior of self-assembling ordered mesoporous materials formed by an organic template with amphiphilic properties and an inorganic precursor in a model solvent. Three classes of inorganic precursors have been modeled: terminal (R-Si-(OEt)3) and bridging ((EtO)3-Si-R-Si-(OEt)3)) organosilica precursors (OSPs), along with pure silica precursors (Si-(OEt)4). Each class has been studied by analyzing its solubility in the solvent and the solvophobicity of the inorganic group. At high surfactant concentrations, periodic ordered structures, such as hexagonally-ordered cylinders or lamellas, can be obtained depending on the OSPs used. Ordered structures were obtained in a wider range of conditions when bridging hydrophilic OSPs have been used, because a higher surfactant concentration was reached in the phase where the material was formed. Terminal and bridging OSPs produced ordered structures only when the organic group is solvophilic. In this case, a partial solubility between the precursor and the solvent or a lower temperature favored the formation of ordered phases. With particular interest, we have analyzed the range of conditions leaving to the formation of cylindrical structures, which have been evaluated according to the pore size distribution, the pore wall thickness, the distribution and the accessibility of the functional organic groups around the pores. The phase behavior has been also evaluated by applying the quasi-chemical theory, which cannot predict the formation of ordered structures, but confirmed the results of simulations when no ordered structures were observed. The study of the phase and aggregation behavior of two different surfactants, one modeled by a linear chain of head segments and the other modeled by a branched-head, permitted us to evaluate some structural differences of the materials obtained.

  14. Rheological properties vs Local Dynamics in model disordered materials at Low Temperature

    E-Print Network [OSTI]

    C. Fusco; T. Albaret; A. Tanguy

    2014-03-31T23:59:59.000Z

    We study the rheological response at low temperature of a sheared model disordered material as a function of the bond rigidity. We find that the flow curves follow a Herschel-Bulkley law, whatever is the bond rigidity, with an exponent close to 0.5. Interestingly, the apparent viscosity can be related to a single relevant time scale $t_{rel}$, suggesting a strong connection between the local dynamics and the global mechanical behaviour. We propose a model based on the competition between the nucleation and the avalanche-like propagation of spatial strain heterogeneities. This model can explain the Herschel-Bulkley exponent on the basis of the size dependence of the heterogeneities on the shear rate.

  15. A Fast Method for SRAM Failure Estimation

    E-Print Network [OSTI]

    Gao, Min

    2012-01-01T23:59:59.000Z

    thesis, a novel and fast failure analysis for SRAM cells isproposed algorithm for SRAM failure analysis is described inAlgorithm for SRAM Failure Analysis Input: random variables

  16. “Playboy Bunny” Sign of Congestive Heart Failure

    E-Print Network [OSTI]

    Hokama, Akira; Arakaki, Shingo; Shibata, Daisuke; Maeshiro, Tatsuji; Kinjo, Fukunori; Fujita, Jiro

    2011-01-01T23:59:59.000Z

    Bunny’’ Sign of Congestive Heart Failure Akira Hokama, MD*to evaluate congestive heart failure. We highlight ‘‘Playboycaused by congestive heart failure. [West J Emerg Med. 2011;

  17. Combination stem cell therapy for heart failure

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    to further analyze his heart failure. Com- plete bloodA: Inflammatory markers in stable heart failure and theirof improvement and readmission in heart failure. Eur J Heart

  18. Modeling the Production of Beta-Delayed Gamma Rays for the Detection of Special Nuclear Materials

    SciTech Connect (OSTI)

    Hall, J M; Pruet, J A; Brown, D A; Descalle, M; Hedstrom, G W; Prussin, S G

    2005-02-14T23:59:59.000Z

    The objective of this LDRD project was to develop one or more models for the production of {beta}-delayed {gamma} rays following neutron-induced fission of a special nuclear material (SNM) and to define a standardized formatting scheme which will allow them to be incorporated into some of the modern, general-purpose Monte Carlo transport codes currently being used to simulate inspection techniques proposed for detecting fissionable material hidden in sea-going cargo containers. In this report, we will describe a Monte Carlo model for {beta}-delayed {gamma}-ray emission following the fission of SNM that can accommodate arbitrary time-dependent fission rates and photon collection histories. The model involves direct sampling of the independent fission yield distributions of the system, the branching ratios for decay of individual fission products and spectral distributions representing photon emission from each fission product and for each decay mode. While computationally intensive, it will be shown that this model can provide reasonably detailed estimates of the spectra that would be recorded by an arbitrary spectrometer and may prove quite useful in assessing the quality of evaluated data libraries and identifying gaps in the libraries. The accuracy of the model will be illustrated by comparing calculated and experimental spectra from the decay of short-lived fission products following the reactions {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f). For general-purpose transport calculations, where a detailed consideration of the large number of individual {gamma}-ray transitions in a spectrum may not be necessary, it will be shown that a simple parameterization of the {gamma}-ray source function can be defined which provides high-quality average spectral distributions that should suffice for calculations describing photons being transported through thick attenuating media. Finally, a proposal for ENDF-compatible formats that describe each of the models and allow for their straightforward use in Monte Carlo codes will be presented.

  19. WaterTransport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization

    SciTech Connect (OSTI)

    J. Vernon Cole; Abhra Roy; Ashok Damle; Hari Dahr; Sanjiv Kumar; Kunal Jain; Ned Djilai

    2012-10-02T23:59:59.000Z

    Water management in Proton Exchange Membrane, PEM, Fuel Cells is challenging because of the inherent conflicts between the requirements for efficient low and high power operation. Particularly at low powers, adequate water must be supplied to sufficiently humidify the membrane or protons will not move through it adequately and resistance losses will decrease the cell efficiency. At high power density operation, more water is produced at the cathode than is necessary for membrane hydration. This excess water must be removed effectively or it will accumulate in the Gas Diffusion Layers, GDLs, between the gas channels and catalysts, blocking diffusion paths for reactants to reach the catalysts and potentially flooding the electrode. As power density of the cells is increased, the challenges arising from water management are expected to become more difficult to overcome simply due to the increased rate of liquid water generation relative to fuel cell volume. Thus, effectively addressing water management based issues is a key challenge in successful application of PEMFC systems. In this project, CFDRC and our partners used a combination of experimental characterization, controlled experimental studies of important processes governing how water moves through the fuel cell materials, and detailed models and simulations to improve understanding of water management in operating hydrogen PEM fuel cells. The characterization studies provided key data that is used as inputs to all state-of-the-art models for commercially important GDL materials. Experimental studies and microscopic scale models of how water moves through the GDLs showed that the water follows preferential paths, not branching like a river, as it moves toward the surface of the material. Experimental studies and detailed models of water and airflow in fuel cells channels demonstrated that such models can be used as an effective design tool to reduce operating pressure drop in the channels and the associated costs and weight of blowers and pumps to force air and hydrogen gas through the fuel cell. Promising improvements to materials structure and surface treatments that can potentially aid in managing the distribution and removal of liquid water were developed; and improved steady-state and freeze-thaw performance was demonstrated for a fuel cell stack under the self-humidified operating conditions that are promising for stationary power generation with reduced operating costs.

  20. Tools for multiaxial validation of behavior laws chosen for modeling hyper-elasticity of rubber-like materials

    E-Print Network [OSTI]

    Chevalier, Luc; 10.1002/pen.10948

    2010-01-01T23:59:59.000Z

    We present an experimental approach to discriminate hyper-elastic models describing the mechanical behavior of rubber-like materials. An evaluation of the displacement field obtained by digital image correlation allows us to evaluate the heterogeneous strain field observed during these tests. We focus on the particular case of hyper-elastic models to simulate the behavior of some rubber-like materials. Assuming incompressibility of the material, the hyper-elastic potential is determined from tension and compression tests. A biaxial loading condition is obtained in a multiaxial testing machine and model predictions are compared with experimental results.

  1. Efficient Failure Detection for Mobile Robots Using Mixed-Abstraction Particle Filters

    E-Print Network [OSTI]

    Stachniss, Cyrill

    Efficient Failure Detection for Mobile Robots Using Mixed-Abstraction Particle Filters Christian the problem of online failure detection and isolation for mobile robots. The goal is to enable a mobile robot failures of mobile robots. It uses a hierarchy of process models to actively validate the model assumptions

  2. Quantitative assessment of mean-field modeling for athermally sheared yield stress materials

    E-Print Network [OSTI]

    Francesco Puosi; Julien Olivier; Kirsten Martens

    2015-01-19T23:59:59.000Z

    We consolidate using molecular dynamic simulations a mean-field scenario for athermally sheared yield stress materials. In a parameter regime that fits the rheological response with a Herschel Bulkley form $=\\sigma_Y+A \\dot{\\gamma}^{1/2}$, we find that stress fluctuations are well described by a mean-field diffusive process induced through the surrounding plastic activity as proposed by the \\Heb-Lequeux model. Our study suggests that the amplitude of this purely mechanical noise is related to the rate of plasticity and the stress release in a plastic event through a possibly generic coupling constant $\\tilde{\\alpha}$.

  3. 3.22 Mechanical Properties of Materials, Spring 2003

    E-Print Network [OSTI]

    Gibson, Lorna J.

    Phenomenology of mechanical behavior of materials at the macroscopic level. Relationship of mechanical behavior to material structure and mechanisms of deformation and failure. Topics include: elasticity, viscoelasticity, ...

  4. Control Model Integrated Management and Assessment System. These materials are from April 2000 and pertain to Savanna

    E-Print Network [OSTI]

    Boone, Randall B.

    Control Model #12;134 Integrated Management and Assessment System. These materials are from AprilView for contacts. Total biomass, by plant groups As you have already likely noticed, the control model includes and dead biomass, for a typical April to July NCA-Savanna Control Model #12;135 Root biomass for herbaceous

  5. Ris-R-1261(EN) Fatigue Degradation and Failure of

    E-Print Network [OSTI]

    . Such applications are for instance rotor blades in wind turbines, helicopter rotor blades, flywheels for energyRisø-R-1261(EN) Fatigue Degradation and Failure of Rotating Composite Structures ­ Materials Characterisation and Underlying Mechanisms E. Kristofer Gamstedt and Svend Ib Andersen Materials Research

  6. Development of a sub-scale dynamics model for pressure relaxation of multi-material cells in Lagrangian hydrodynamics

    SciTech Connect (OSTI)

    Harrison, Alan K [Los Alamos National Laboratory; Shashkov, Mikhail J [Los Alamos National Laboratory; Fung, Jimmy [Los Alamos National Laboratory; Canfield, Thomas R [Los Alamos National Laboratory; Kamm, James R [SNLA

    2010-10-14T23:59:59.000Z

    We have extended the Sub-Scale Dynamics (SSD) closure model for multi-fluid computational cells. Volume exchange between two materials is based on the interface area and a notional interface translation velocity, which is derived from a linearized Riemann solution. We have extended the model to cells with any number of materials, computing pressure-difference-driven volume and energy exchange as the algebraic sum of pairwise interactions. In multiple dimensions, we rely on interface reconstruction to provide interface areas and orientations, and centroids of material polygons. In order to prevent unphysically large or unmanageably small material volumes, we have used a flux-corrected transport (FCT) approach to limit the pressure-driven part of the volume exchange. We describe the implementation of this model in two dimensions in the FLAG hydrodynamics code. We also report on Lagrangian test calculations, comparing them with others made using a mixed-zone closure model due to Tipton, and with corresponding calculations made with only single-material cells. We find that in some cases, the SSD model more accurately predicts the state of material in mixed cells. By comparing the algebraic forms of both models, we identify similar dependencies on state and dynamical variables, and propose explanations for the apparent higher fidelity of the SSD model.

  7. Eliciting a human understandable model of ice adhesion strength for rotor blade leading edge materials from uncertain experimental data

    E-Print Network [OSTI]

    Granada, Universidad de

    Eliciting a human understandable model of ice adhesion strength for rotor blade leading edge: Genetic Fuzzy Systems Fuzzy rule-based classifiers Vague data Isotropic materials Ice-phobic materials Shear adhesion strength a b s t r a c t The published ice adhesion performance data of novel ``ice

  8. Error bounds for space-time discretizations of a 3D model for shape-memory materials

    E-Print Network [OSTI]

    Stefanelli, Ulisse

    Error bounds for space-time discretizations of a 3D model for shape-memory materials Alexander in shape- memory materials. After recalling existence and uniqueness results, a fully evolution of shape-memory alloys (SMAs). The latter are metallic alloys showing some surprising thermo

  9. A new method for modelling roofing materials emissions on the city scale: Application for zinc in the city of Crteil

    E-Print Network [OSTI]

    Boyer, Edmond

    1 A new method for modelling roofing materials emissions on the city scale: Application for zinc as an important source of environmental pollution. Roofing materials, in particular the metallic ones Directive (2000/60 CE), an accurate evaluation of contaminant flows from roofs is thus required on the city

  10. Steam generator tube failures

    SciTech Connect (OSTI)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01T23:59:59.000Z

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  11. Analytical models to evaluate system performance measures for vehicle based material-handling systems under various dispatching policies

    E-Print Network [OSTI]

    Lee, Moonsu

    2005-08-29T23:59:59.000Z

    -route material-handling systems from two different perspectives: the workcenters?? point of view and the transporters?? point of view. The state-dependent nature of the transportation time is considered here for more accurate analytical approximation models...

  12. Demonstration of a computer model for residual radioactive material guidelines, RESRAD

    SciTech Connect (OSTI)

    Yu, C.; Yuan, Y.C.; Zielen, A.J.; Wallo, A. III (Argonne National Lab., IL (USA); USDOE, Washington, DC (USA))

    1989-01-01T23:59:59.000Z

    A computer model was developed to calculate residual radioactive material guidelines for the US Department of Energy (DOE). This model, called RESRAD, can be run on IBM or IBM-compatible microcomputer. Seven potential exposure pathways from contaminated soil are analyzed, including external radiation exposure and internal radiation exposure from inhalation and food digestion. The RESRAD code has been applied to several DOE sites to derive soil cleanup guidelines. The experience gained indicates that a comprehensive set of site-specific hydrogeologic and geochemical input parameters must be used for a realistic pathway analysis. The RESRAD code is a useful tool; it is easy to run and very user-friendly. 6 refs., 12 figs.

  13. Vulnerability Assessment for Cascading Failures in Electric Power Systems

    SciTech Connect (OSTI)

    Baldick, R.; Chowdhury, Badrul; Dobson, Ian; Dong, Zhao Yang; Gou, Bei; Hawkins, David L.; Huang, Zhenyu; Joung, Manho; Kim, Janghoon; Kirschen, Daniel; Lee, Stephen; Li, Fangxing; Li, Juan; Li, Zuyi; Liu, Chen-Ching; Luo, Xiaochuan; Mili, Lamine; Miller, Stephen; Nakayama, Marvin; Papic, Milorad; Podmore, Robin; Rossmaier, John; Schneider, Kevin P.; Sun, Hongbin; Sun, Kai; Wang, David; Wu, Zhigang; Yao, Liangzhong; Zhang, Pei; Zhang, Wenjie; Zhang, Xiaoping

    2008-09-10T23:59:59.000Z

    Cascading failures present severe threats to power grid security, and thus vulnerability assessment of power grids is of significant importance. Focusing on analytic methods, this paper reviews the state of the art of vulnerability assessment methods in the context of cascading failures in three categories: steady-state modeling based analysis; dynamic modeling analysis; and non-traditional modeling approaches. The impact of emerging technologies including phasor technology, high-performance computing techniques, and visualization techniques on the vulnerability assessment of cascading failures is then addressed, and future research directions are presented.

  14. A model for self-defocusing in laser drilling of polymeric materials

    SciTech Connect (OSTI)

    Zhang Chong; Quick, Nathaniel R.; Kar, Aravinda [Department of Mechanical, Materials and Aerospace Engineering, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States); AppliCote Associates, LLC, 1445 Dolgner Place, Suite 23, Sanford, Florida 32771 (United States); College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States)

    2008-01-01T23:59:59.000Z

    A numerical thermal model is presented for laser microvias drilling in multilayer electronic substrates with Nd:YAG (YAG denotes yttrium aluminum garnet) and CO{sub 2} lasers. Such substrates have different optical properties such as the refractive index and absorption coefficient at these two laser wavelengths, resulting in different drilling mechanisms. Since the skin depth of the polymer is large for both the lasers, volumetric heating is considered in the model. As soon as a small cavity is formed during the drilling process, the concave curvature of the drilling front acts as a concave lens that diverges the incident laser beam. This self-defocusing effect can greatly reduce the drilling speed as predicted by the model. This effect makes the refractive index of the substrate at different wavelengths an important parameter for laser drilling. The model was used to calculate the laser ablation thresholds which were found to be 8 and 56 J/cm{sup 2} for the CO{sub 2} and Nd:YAG lasers respectively. Due to the expulsion of materials because of high internal pressures in the case of Nd:YAG laser microvia drilling, the ablation threshold may be far below the calculated value. A particular laser beam shape, such as pitch fork, was found to drill better holes than the Gaussian beam.

  15. How to confirm and exclude different models of material properties in the Casimir effect

    E-Print Network [OSTI]

    V. M. Mostepanenko

    2014-11-17T23:59:59.000Z

    We formulate a method allowing to confirm or exclude the alternative models of material properties at some definite confidence level in experiments on measuring the Casimir force. The method is based on the consideration of differences between the theoretical and mean measured quantities and the confidence intervals for these differences found at sufficiently high or low confidence probabilities. The developed method is applied to the data of four recent experiments on measuring the gradient of the Casimir force by means of a dynamic atomic force microscope. It is shown that in experiments with Au-Au and Ni-Ni test bodies, where the Drude model approach is excluded at a 95% confidence level, the plasma model approach agrees with the data at higher than 90% confidence. In experiments using an Au sphere interacting with either a Ni plate or a graphene-coated substrate the measurement data agree with the common prediction of the Drude and plasma model approaches and theory using the polarization tensor at 90% and 80% confidence levels, respectively.

  16. Lattice Boltzmann modeling of the effective thermal conductivity for fibrous materials

    E-Print Network [OSTI]

    Wang, Moran; He, Jihuan; Yu, Jianyong; Pan, Ning

    2007-01-01T23:59:59.000Z

    composites. Journal of Materials Science, 1997. 32(8): p.problem. Computational Materials Science, 2004. 31(1-2): p.properties. Journal of Materials Research, 2001. 16(1): p.

  17. Modeling and Design of Material Separation Systems with Applications to Recycling

    E-Print Network [OSTI]

    Wolf, Malima Isabelle, 1981-

    2011-01-01T23:59:59.000Z

    Material separation technology is critical to the success of the material recycling industry. End-of-life products, post-consumer waste, industrial excess, or otherwise collected materials for reuse are typically mixed ...

  18. Chemical Reaction Mechanisms for Modeling the Fluorocarbon Plasma Etch of Silicon Oxide and Related Materials

    SciTech Connect (OSTI)

    HO,PAULINE; JOHANNES,JUSTINE E.; BUSS,RICHARD J.; MEEKS,ELLEN

    2001-05-01T23:59:59.000Z

    As part of a project with SEMATECH, detailed chemical reaction mechanisms have been developed that describe the gas-phase and surface chemistry occurring during the fluorocarbon plasma etching of silicon dioxide and related materials. The fluorocarbons examined are C{sub 2}F{sub 6}, CHF{sub 3} and C{sub 4}F{sub 8}, while the materials studied are silicon dioxide, silicon, photoresist, and silica-based low-k dielectrics. These systems were examined at different levels, ranging from in-depth treatment of C{sub 2}F{sub 6} plasma etch of oxide, to a fairly cursory examination of C{sub 4}F{sub 8} etch of the low-k dielectric. Simulations using these reaction mechanisms and AURORA, a zero-dimensional model, compare favorably with etch rates measured in three different experimental reactors, plus extensive diagnostic absolute density measurements of electron and negative ions, relative density measurements of CF, CF{sub 2}, SiF and SiF{sub 2} radicals, ion current densities, and mass spectrometric measurements of relative ion densities.

  19. Failure of man-made cavities in salt and surface subsidence due to sulfur mining

    SciTech Connect (OSTI)

    Coates, G.K.; Lee, C.A.; McClain, W.C.; Senseny, P.E.

    1981-01-01T23:59:59.000Z

    An engineering data base relevant to subsidence due to sulfur mining and to structural failure of cavities in salt is established, evaluated and documented. Nineteen failure events are discussed. Based on these documented failure events, capabilities of and inputs to a mathematical model of cavity failure are determined. Two failure events are adequately documented for use in model verification studies. A conclusion of this study that is pertinent to the Strategic Petroleum Reserve is that cavity failures in dome salt are fairly rare, but that as the number of large cavities (especially those having large roof spans) increases, failures will probably be more common unless stability and failure mechanisms of cavities are better understood.

  20. Failure Atlas for Rolling Bearings in Wind Turbines

    SciTech Connect (OSTI)

    Tallian, T. E.

    2006-01-01T23:59:59.000Z

    This Atlas is structured as a supplement to the book: T.E. Tallian: Failure Atlas for Hertz Contact Machine Elements, 2nd edition, ASME Press New York, (1999). The content of the atlas comprises plate pages from the book that contain bearing failure images, application data, and descriptions of failure mode, image, and suspected failure causes. Rolling bearings are a critical component of the mainshaft system, gearbox and generator in the rapidly developing technology of power generating wind turbines. The demands for long service life are stringent; the design load, speed and temperature regimes are demanding and the environmental conditions including weather, contamination, impediments to monitoring and maintenance are often unfavorable. As a result, experience has shown that the rolling bearings are prone to a variety of failure modes that may prevent achievement of design lives. Morphological failure diagnosis is extensively used in the failure analysis and improvement of bearing operation. Accumulated experience shows that the failure appearance and mode of failure causation in wind turbine bearings has many distinguishing features. The present Atlas is a first effort to collect an interpreted database of specifically wind turbine related rolling bearing failures and make it widely available. This Atlas is structured as a supplement to the book: T. E. Tallian: Failure Atlas for Hertz Contact Machine Elements, 2d edition, ASME Press New York, (1999). The main body of that book is a comprehensive collection of self-contained pages called Plates, containing failure images, bearing and application data, and three descriptions: failure mode, image and suspected failure causes. The Plates are sorted by main failure mode into chapters. Each chapter is preceded by a general technical discussion of the failure mode, its appearance and causes. The Plates part is supplemented by an introductory part, describing the appearance classification and failure classification systems used, and by several indexes. The present Atlas is intended as a supplement to the book. It has the same structure but contains only Plate pages, arranged in chapters, each with a chapter heading page giving a short definition of the failure mode illustrated. Each Plate page is self contained, with images, bearing and application data, and descriptions of the failure mode, the images and the suspected causes. Images are provided in two resolutions: The text page includes 6 by 9 cm images. In addition, high resolution image files are attached, to be retrieved by clicking on their 'push pin' icon. While the material in the present Atlas is self-contained, it is nonetheless a supplement to the book and the complete interpretation of the terse image descriptions and of the system underlying the failure code presupposes familiarity with the book. Since this Atlas is a supplement to the book, its chapter numbering follows that of the book. Not all failure modes covered in the book have been found among the observed wind turbines. For that reason, and because of the omission of introductory matter, the chapter numbers in this Atlas are not a continuous sequence.

  1. Condition Data Aggregation with Application to Failure Rate Calculation of Power Transformers

    E-Print Network [OSTI]

    Condition Data Aggregation with Application to Failure Rate Calculation of Power Transformers for condition monitoring and failure rate prediction of power transformers. Specif- ically, the system uses to the substation, to develop Hidden Markov Models (HMMs) which transform the condition data into failure

  2. Constraint-Based Routing Models for the Transport of Radioactive Materials

    SciTech Connect (OSTI)

    Peterson, Steven K [ORNL

    2015-01-01T23:59:59.000Z

    The Department of Energy (DOE) has a historic programmatic interest in the safe and secure routing, tracking, and transportation risk analysis of radiological materials in the United States. In order to address these program goals, DOE has funded the development of several tools and related systems designed to provide insight to planners and other professionals handling radioactive materials shipments. These systems include the WebTRAGIS (Transportation Routing Analysis Geographic Information System) platform. WebTRAGIS is a browser-based routing application developed at Oak Ridge National Laboratory (ORNL) focused primarily on the safe transport of spent nuclear fuel from US nuclear reactors via railway, highway, or waterway. It is also used for the transport planning of low-level radiological waste to depositories such as the Waste Isolation Pilot Plant (WIPP) facility. One particular feature of WebTRAGIS is its coupling with high-resolution population data from ORNL s LandScan project. This allows users to obtain highly accurate population count and density information for use in route planning and risk analysis. To perform the routing and risk analysis WebTRAGIS incorporates a basic routing model methodology, with the additional application of various constraints designed to mimic US Department of Transportation (DOT), DOE, and Nuclear Regulatory Commission (NRC) regulations. Aside from the routing models available in WebTRAGIS, the system relies on detailed or specialized modal networks for the route solutions. These include a highly detailed network model of the US railroad system, the inland and coastal waterways, and a specialized highway network that focuses on the US interstate system and the designated hazardous materials and Highway Route Controlled Quantity (HRCQ) -designated roadways. The route constraints in WebTRAGIS rely upon a series of attributes assigned to the various components of the different modal networks. Routes are determined via a constrained shortest-path Dijkstra algorithm that has an assigned impedance factor. The route constraints modify the various impedance weights to bias or prefer particular network characteristics as desired by the user. Both the basic route model and the constrained impedance function calculations are determined by a series of network characteristics and shipment types. The study examines solutions under various constraints modeled by WebTRAGIS including possible routes from select shut-down reactor sites in the US to specific locations in the US. For purposes of illustration, the designated destinations are Oak Ridge National Laboratory in Tennessee and the Savannah River Site in South Carolina. To the degree that routes express sameness or variety under constraints serves to illustrate either a) the determinism of particular transport modes by either configuration or regulatory compliance, and/or b) the variety of constrained routes that are regulation compliant but may not be operationally feasible.

  3. Lightweighting Automotive Materials for Increased Fuel Efficiency and Delivering Advanced Modeling and Simulation Capabilities to U.S. Manufacturers

    SciTech Connect (OSTI)

    Hale, Steve

    2013-09-11T23:59:59.000Z

    Abstract The National Center for Manufacturing Sciences (NCMS) worked with the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), to bring together research and development (R&D) collaborations to develop and accelerate the knowledgebase and infrastructure for lightweighting materials and manufacturing processes for their use in structural and applications in the automotive sector. The purpose/importance of this DOE program: • 2016 CAFÉ standards. • Automotive industry technology that shall adopt the insertion of lightweighting material concepts towards manufacturing of production vehicles. • Development and manufacture of advanced research tools for modeling and simulation (M&S) applications to reduce manufacturing and material costs. • U.S. competitiveness that will help drive the development and manufacture of the next generation of materials. NCMS established a focused portfolio of applied R&D projects utilizing lightweighting materials for manufacture into automotive structures and components. Areas that were targeted in this program: • Functionality of new lightweighting materials to meet present safety requirements. • Manufacturability using new lightweighting materials. • Cost reduction for the development and use of new lightweighting materials. The automotive industry’s future continuously evolves through innovation, and lightweight materials are key in achieving a new era of lighter, more efficient vehicles. Lightweight materials are among the technical advances needed to achieve fuel/energy efficiency and reduce carbon dioxide (CO2) emissions: • Establish design criteria methodology to identify the best materials for lightweighting. • Employ state-of-the-art design tools for optimum material development for their specific applications. • Match new manufacturing technology to production volume. • Address new process variability with new production-ready processes.

  4. Engineered materials characterization report for the Yucca Mountain Site Characterization Project. Volume 3: Corrosion and data modeling

    SciTech Connect (OSTI)

    Van Konynenburg, R.A.; McCright, R.D. [Lawrence Livermore National Lab., CA (United States); Roy, A.K. [B and W Fuel Co., Lynchburg, VA (United States); Jones, D.A. [Nevada Univ., Reno, NV (United States)

    1995-08-01T23:59:59.000Z

    This three-volume report serves several purposes. The first volume provides an introduction to the engineered materials effort for the Yucca Mountain Site Characterization Project. It defines terms and outlines the history of selection and characterization of these materials. A summary of the recent engineered barrier materials characterization workshop is presented, and the current candidate materials are listed. The second volume tabulates design data for engineered materials, and the third volume is devoted to corrosion data, radiation effects on corrosion, and corrosion modeling. The second and third volumes are intended to be evolving documents, to which new data will be added as they become available from additional studies. The initial version of Volume 3 is devoted to information currently available for environments most similar to those expected in the potential Yucca Mountain repository. This is volume three.

  5. INTERFACE CRACK PROPAGATION IN POROUS AND TIME-DEPENDENT MATERIALS ANALYZED WITH

    E-Print Network [OSTI]

    Boyer, Edmond

    INTERFACE CRACK PROPAGATION IN POROUS AND TIME-DEPENDENT MATERIALS ANALYZED WITH DISCRETE MODELS and the FPZ. From the point of view of design of structures, e.g. reinforced concrete structures, this size size, size effects, creep, ageing, fracture, viscoelastic- ity, time effect, concrete failure, discrete

  6. Computational mesoscale modelling of concrete material under high strain rate loading 

    E-Print Network [OSTI]

    Song, Zhenhuan

    2013-07-01T23:59:59.000Z

    Cement-based composite materials are widely used in engineering applications. The strength and damage patterns of such materials depend upon the properties of the constituent components as well as the microstructure. ...

  7. Dielectric spectroscopy at the nanoscale by atomic force microscopy: A simple model linking materials properties and experimental response

    SciTech Connect (OSTI)

    Miccio, Luis A., E-mail: luisalejandro-miccio@ehu.es; Colmenero, Juan [Centro de Física de Materiales (CSIC-UPV/EHU), P. M. de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center, P. M. de Lardizabal 4, 20018 San Sebastián (Spain); Departamento de Física de Materiales (UPV/EHU), 20080 San Sebastián (Spain); Kummali, Mohammed M.; Alegría, Ángel [Centro de Física de Materiales (CSIC-UPV/EHU), P. M. de Lardizabal 5, 20018 San Sebastián (Spain); Departamento de Física de Materiales (UPV/EHU), 20080 San Sebastián (Spain); Schwartz, Gustavo A. [Centro de Física de Materiales (CSIC-UPV/EHU), P. M. de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center, P. M. de Lardizabal 4, 20018 San Sebastián (Spain)

    2014-05-14T23:59:59.000Z

    The use of an atomic force microscope for studying molecular dynamics through dielectric spectroscopy with spatial resolution in the nanometer scale is a recently developed approach. However, difficulties in the quantitative connection of the obtained data and the material dielectric properties, namely, frequency dependent dielectric permittivity, have limited its application. In this work, we develop a simple electrical model based on physically meaningful parameters to connect the atomic force microscopy (AFM) based dielectric spectroscopy experimental results with the material dielectric properties. We have tested the accuracy of the model and analyzed the relevance of the forces arising from the electrical interaction with the AFM probe cantilever. In this way, by using this model, it is now possible to obtain quantitative information of the local dielectric material properties in a broad frequency range. Furthermore, it is also possible to determine the experimental setup providing the best sensitivity in the detected signal.

  8. FRACTURE FAILURE CRITERIA OF SOFC PEN STRUCTURE

    SciTech Connect (OSTI)

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Qu, Jianmin

    2007-04-30T23:59:59.000Z

    Thermal stresses and warpage of the PEN are unavoidable due to the temperature changes from the stress-free sintering temperature to room temperature and mismatch of the coefficients of thermal expansion (CTE) of various layers in the PEN structures of solid oxide fuel cells (SOFC) during the PEN manufacturing process. In the meantime, additional mechanical stresses will also be created by mechanical flattening during the stack assembly process. The porous nature of anode and cathode in the PEN structures determines presence of the initial flaws and crack on the interfaces of anode/electrolyte/cathode and in the interior of the materials. The sintering/assembling induced stresses may cause the fracture failure of PEN structure. Therefore, fracture failure criteria for SOFC PEN structures is developed in order to ensure the structural integrity of the cell and stack of SOFC. In this paper, the fracture criteria based on the relationship between the critical energy release rate and critical curvature and maximum displacement of the warped cells caused by the temperature changes as well as mechanical flattening process is established so that possible failure of SOFC PEN structures may be predicted deterministically by the measurement of the curvature and displacement of the warped cells.

  9. Progress In Electromagnetics Research B, Vol. 15, 197215, 2009 MODELING OF SHIELDING COMPOSITE MATERIALS

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    ­4]. These composites may contain metal or carbon particles [5, 6]. Carbon-fiber laminate woven materials are known. Composite dielectric materials that contain randomly distributed conductive inclusions, including carbon frequencies [10­12]. Recently, interest in carbon- containing composite materials for RF and microwave

  10. Optical fiber reliability models M. John Matthewson

    E-Print Network [OSTI]

    Matthewson, M. John

    3 Optical fiber reliability models M. John Matthewson Fiber Optic Materials Research Program Systems containing optical fiber have design lives on the order of decades so that models for assessing and promising areas for future work are proposed. 1. INTRODUCTION Mechanical failure of optical fiber must

  11. Simulations of Failure via Three-Dimensional Cracking in Fuel Cladding for Advanced Nuclear Fuels

    SciTech Connect (OSTI)

    Lu, Hongbing; Bukkapatnam, Satish; Harimkar, Sandip; Singh, Raman; Bardenhagen, Scott

    2014-01-09T23:59:59.000Z

    Enhancing performance of fuel cladding and duct alloys is a key means of increasing fuel burnup. This project will address the failure of fuel cladding via three-dimensional cracking models. Researchers will develop a simulation code for the failure of the fuel cladding and validate the code through experiments. The objective is to develop an algorithm to determine the failure of fuel cladding in the form of three-dimensional cracking due to prolonged exposure under varying conditions of pressure, temperature, chemical environment, and irradiation. This project encompasses the following tasks: 1. Simulate 3D crack initiation and growth under instantaneous and/or fatigue loads using a new variant of the material point method (MPM); 2. Simulate debonding of the materials in the crack path using cohesive elements, considering normal and shear traction separation laws; 3. Determine the crack propagation path, considering damage of the materials incorporated in the cohesive elements to allow the energy release rate to be minimized; 4. Simulate the three-dimensional fatigue crack growth as a function of loading histories; 5. Verify the simulation code by comparing results to theoretical and numerical studies available in the literature; 6. Conduct experiments to observe the crack path and surface profile in unused fuel cladding and validate against simulation results; and 7. Expand the adaptive mesh refinement infrastructure parallel processing environment to allow adaptive mesh refinement at the 3D crack fronts and adaptive mesh merging in the wake of cracks. Fuel cladding is made of materials such as stainless steels and ferritic steels with added alloying elements, which increase stability and durability under irradiation. As fuel cladding is subjected to water, chemicals, fission gas, pressure, high temperatures, and irradiation while in service, understanding performance is essential. In the fast fuel used in advanced burner reactors, simulations of the nuclear fuels are critical to understand the burnup, and thus the fuel efficiency.

  12. The Smart Engineering Apprentice (SEA) Project is an advanced artificial intelligence model that aims to predict the future failure of rod pump units. Innovative and modern, this

    E-Print Network [OSTI]

    Shahabi, Cyrus

    The Smart Engineering Apprentice (SEA) Project is an advanced artificial intelligence model system is the apprentice of field experts, and `learns' from experts through their past experiences

  13. The Smart Engineering Apprentice (SEA) Project is an advanced artificial intelligence model that aims to predict the future failure of rod pump units. Innovative and modern, this novel

    E-Print Network [OSTI]

    Wang, Hai

    The Smart Engineering Apprentice (SEA) Project is an advanced artificial intelligence model system is the apprentice of field experts, and ,,learns from experts through their past experiences

  14. Autonomous thruster failure recovery for underactuated spacecraft

    E-Print Network [OSTI]

    Pong, Christopher Masaru

    2010-01-01T23:59:59.000Z

    Thruster failures historically account for a large percentage of failures that have occurred on orbit. Therefore, autonomous thruster failure detection, isolation, and recovery (FDIR) is an essential component to any robust ...

  15. FAILURE DATA ANALYSIS OF THE SUPERHILAC RADIO FREQUENCY SUBSYSTEM

    E-Print Network [OSTI]

    Chang, Mark K.

    2012-01-01T23:59:59.000Z

    Applications to Failure Data Analysis," in RELIABILITY ANDLBL-8631 FAILURE DATA ANALYSIS OF THE SUPERHILAC RADIOinterest in our failure data analysis. If the failure rate

  16. Statistical analysis of cascading failures in power grids

    SciTech Connect (OSTI)

    Chertkov, Michael [Los Alamos National Laboratory; Pfitzner, Rene [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory

    2010-12-01T23:59:59.000Z

    We introduce a new microscopic model of cascading failures in transmission power grids. This model accounts for automatic response of the grid to load fluctuations that take place on the scale of minutes, when optimum power flow adjustments and load shedding controls are unavailable. We describe extreme events, caused by load fluctuations, which cause cascading failures of loads, generators and lines. Our model is quasi-static in the causal, discrete time and sequential resolution of individual failures. The model, in its simplest realization based on the Directed Current description of the power flow problem, is tested on three standard IEEE systems consisting of 30, 39 and 118 buses. Our statistical analysis suggests a straightforward classification of cascading and islanding phases in terms of the ratios between average number of removed loads, generators and links. The analysis also demonstrates sensitivity to variations in line capacities. Future research challenges in modeling and control of cascading outages over real-world power networks are discussed.

  17. Image-Based Multiscale Modeling of Poroelastic Biological Materials with Application to Bones

    E-Print Network [OSTI]

    Yang, Judy

    2012-01-01T23:59:59.000Z

    two-scale problems in geomechanics, Int J Numer Anal Methodsbeen initiated in geomechanics. Due to different subjects ofhas been extended from geomechanics to material science and

  18. A model for materials scientists: Water runs off the surface of a lotus leaf without a trace. Researchers

    E-Print Network [OSTI]

    on the water, not only dry but, most importantly, clean. As the water runs off, it rinses away the dirt, whichA model for materials scientists: Water runs off the surface of a lotus leaf without a trace. Researchers in Mainz use this concept to develop coatings that repel both water and oil. #12;TEXT ROLAND

  19. Submission of manuscript to Energy and Buildings A thermal model for Phase Change Materials in a building roof for a

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Submission of manuscript to Energy and Buildings A thermal model for Phase Change Materials in "Energy and Buildings 70 (2014) http://www.sciencedirect.com/science/article/pii/ S0378778813007962" DOI : 10.1016/j.enbuild.2013.11.079 #12;Manuscript submitted to Energy and Buildings S.GUICHARD 2013 2

  20. Verification and Validation of EnergyPlus Conduction Finite Difference and Phase Change Material Models for Opaque Wall Assemblies

    SciTech Connect (OSTI)

    Tabares-Velasco, P. C.; Christensen, C.; Bianchi, M.; Booten, C.

    2012-07-01T23:59:59.000Z

    Phase change materials (PCMs) represent a potential technology to reduce peak loads and HVAC energy consumption in buildings. There are few building energy simulation programs that have the capability to simulate PCM but their accuracy has not been completely tested. This report summarizes NREL efforts to develop diagnostic tests cases to obtain accurate energy simulations when PCMs are modeled in residential buildings.

  1. Multiscale modeling of fluid transport in heterogeneous materials using discrete Boltzmann methods

    E-Print Network [OSTI]

    Bentz, Dale P.

    transport in porous materials like ceramics, concrete, soils, and rocks plays an impor- tant role in many geometries like porous materials. Here, we review some of our previous work and discuss some recent environmental and technological processes [11.For example, the service life and durability of concrete can

  2. Modelling the mechanical interaction between flowing materials and retaining wire structures

    E-Print Network [OSTI]

    Gagliardini, Olivier

    Recherche Erosion Torrentielle Neige et Avalanches, Grenoble, France b EI Montagne, Grenoble, France c material and an open structure made of a metallic mesh. This paper presents some theoretical results, first material maintained in part by an open structure, for instance a wire mesh, is frequently encountered

  3. Evaluation and Modeling of Edge-Seal Materials for Photovoltaic Applications

    SciTech Connect (OSTI)

    Kempe, M. D.; Dameron, A. A.; Moricone, T. J.; Reese, M. O.

    2011-02-01T23:59:59.000Z

    Because of the sensitivity of some photovoltaic devices to moisture-induced corrosion, they are packaged using impermeable front- and back-sheets along with an edge seal to prevent moisture ingress. Evaluation of edge seal materials can be difficult because of the low permeation rates involved and/or non-Fickian behavior. Here, using a Ca film deposited on a glass substrate, we demonstrate the evaluation of edge seal materials in a manner that effectively duplicates their use in a photovoltaic application and compare the results with standard methods for measuring water vapor transport. We demonstrate how moisture permeation data from polymer films can be used to estimate moisture ingress rates and compare the results of these two methods. Encapsulant materials were also evaluated for comparison and to highlight the need for edge seals. Of the materials studied, desiccant filled polyisobutylene materials demonstrate by far the best potential to keep moisture out for a 20 to 30 year lifetime.

  4. PACER -- A fast running computer code for the calculation of short-term containment/confinement loads following coolant boundary failure. Volume 1: Code models and correlations

    SciTech Connect (OSTI)

    Sienicki, J.J.

    1997-06-01T23:59:59.000Z

    A fast running and simple computer code has been developed to calculate pressure loadings inside light water reactor containments/confinements under loss-of-coolant accident conditions. PACER was originally developed to calculate containment/confinement pressure and temperature time histories for loss-of-coolant accidents in Soviet-designed VVER reactors and is relevant to the activities of the US International Nuclear Safety Center. The code employs a multicompartment representation of the containment volume and is focused upon application to early time containment phenomena during and immediately following blowdown. Flashing from coolant release, condensation heat transfer, intercompartment transport, and engineered safety features are described using best estimate models and correlations often based upon experiment analyses. Two notable capabilities of PACER that differ from most other containment loads codes are the modeling of the rates of steam and water formation accompanying coolant release as well as the correlations for steam condensation upon structure.

  5. Model error estimation in composite impact response prediction using hierarchical Bayes networks

    E-Print Network [OSTI]

    Salas Mendez, Pablo Antonio

    2010-01-01T23:59:59.000Z

    in Progressive Failure Analysis . . . 4.0.2 ModelingPuck and H. Schurmann, “Failure analysis of frp laminates byComposite laminate failure analysis using multi- continuum

  6. Quality of Service of Crash-Recovery Failure Detectors 

    E-Print Network [OSTI]

    Ma, Tiejun

    2007-11-07T23:59:59.000Z

    problem when the monitored target is resilient and recovers after failure. To the best of our knowledge, this is the first work to provide an analysis of crash-recovery failure detection from the QoS perspective....We develop a probabilistic model of the behavior of a crash-recovery target, i.e. one which has the ability to recover from the crash state. We show that the fail-free run and the crash-stop run are special cases of the crash-recovery run with mean time to failure (MTTF) approaching to infinity and mean time to recovery (MTTR) approaching to infinity, respectively. We extend the previously published QoS metrics to allow the measurement of the recovery speed, and the definition of the completeness property of a failure detector. Then, the impact of the dependability of the crash-recovery target on the QoS bounds for such a crash-recovery failure detector is analyzed using general dependability metrics, such as MTTF and MTTR, based on an approximate probabilistic model of the two-process failure detection system. Then according to our approximate model, we show how to estimate the failure detector’s parameters to achieve a required QoS, based on Chen et al.’s NFD-S algorithm analytically, and how to execute the configuration procedure of this crash-recovery failure detector....In order to make the failure detector adaptive to the target’s crash-recovery behavior and enable the autonomy of the monitoring procedure, we propose two types of recovery detection protocols. One is a reliable recovery detection protocol, which can guarantee to detect each occurring failure and recovery by adopting persistent storage. The other is a lightweight recovery detection protocol, which does not guarantee to detect every failure and recovery but which reduces the system overhead. Both of these recovery detection protocols improve the completeness without reducing the other QoS aspects of a failure detector. In addition, we also demonstrate how to estimate the inputs, such as the dependability metrics, using the failure detector itself....In order to evaluate our analytical work, we simulate the following failure detection algorithms: the simple heartbeat timeout algorithm, the NFD-S algorithm and the NFDS algorithm with the lightweight recovery detection protocol, for various values of MTTF and MTTR. The simulation results show that the dependability of a recoverable monitored target could have significant impact on the QoS of such a failure detector. This conforms well to our models and analysis. We show that in the case of reasonable long MTTF, the NFD-S algorithm with the lightweight recovery detection protocol exhibits better QoS than the NFD-S algorithm for the completeness of a crash-recovery failure detector, and similarly for other QoS metrics....

  7. battery materials | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    battery materials battery materials Leads No leads are available at this time. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations. Abstract: The...

  8. Physical understanding and modeling of chemical mechanical planarization in dielectric materials

    E-Print Network [OSTI]

    Xie, Xiaolin, Ph. D. Massachusetts Institute of Technology

    2007-01-01T23:59:59.000Z

    Chemical mechanical planarization (CMP) has become the enabling planarization technique of choice for current and emerging silicon integrated circuit (IC) fabrication processes. This work studies CMP in dielectric materials ...

  9. Modeling VOC sorption of building materials and its impact on indoor air quality

    E-Print Network [OSTI]

    Zhang, Jinsong, 1975-

    2001-01-01T23:59:59.000Z

    Sorption of volatile organic compounds (VOCs) by building materials can have significant effect on the indoor VOC concentration levels and indoor air quality in buildings. The objective of this study was to investigate ...

  10. Estimation of Distributed Parameters in Permittivity Models of Composite Dielectric Materials Using

    E-Print Network [OSTI]

    Metric Framework, inorganic glass. 1 #12;1 Introduction Complex materials such as ceramic matrix spectroscopy has been shown to have sensitivity to heat treated ceramic thermal barrier coatings, which

  11. Adaptive Hierarchical Multiscale Framework for Modeling the Deformation of Ultra-Strong Nano-structured Materials

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    , we plan to investigate the deformation characteris- tics of two classes of nano-structured materials. The proposed research will also impact graduate education world-wide by the developme

  12. Reactive Ballistic Deposition of Nanostructured Model Materials for Electrochemical Energy Conversion and Storage

    SciTech Connect (OSTI)

    Flaherty, David W.; Hahn, Nathan T.; May, Robert A.; Berglund, Sean P.; Lin, Yong-Mao; Stevenson, Keith J.; Dohnalek, Zdenek; Kay, Bruce D.; Mullins, C. Buddie

    2012-03-20T23:59:59.000Z

    Finely structured, supported thin films offer a host of opportunities for fundamental and applied research. Nanostructured materials often exhibit physical properties which differ from their bulk counterparts due to the increased importance of the surface in determining the thermodynamics and behavior of the system. Thus, control of the characteristic size, porosity, morphology, and surface area presents opportunities to tailor new materials which are useful platforms for elucidating the fundamental processes related to energy conversion and storage. The ability to produce high purity materials with direct control of relevant film parameters such as porosity, film thickness, and film morphology is of immediate interest in the fields of electrochemistry, photocatalysis, and thermal catalysis. Studies of various photoactive materials have introduced questions concerning the effects of film architecture and surface structure on the performance of the materials, while recent work has demonstrated that nanostructured, mesoporous, or disordered materials often deform plastically, making them robust in applications where volumetric expansion and phase transformations occur, such as in materials for lithium-ion batteries. Moreover, renewed emphasis has been placed on the formation of semi-conductive electrodes with controlled pore-size and large surface areas for the study and application of pseudo-capacitance and cation insertion processes for electrical energy storage. Understanding how the performance of such materials depends on morphology, porosity, and surface structure and area requires a synthesis technique which provides for incremental variations in structure and facilitates assessment of the performance with the appropriate analytical tools, preferably those that provide both structural information and kinetic insight into photoelectrochemical processes.

  13. Modeling most likely pathways for smuggling radioactive and special nuclear materials on a worldwide multimodal transportation network

    SciTech Connect (OSTI)

    Saeger, Kevin J [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    Nuclear weapons proliferation is an existing and growing worldwide problem. To help with devising strategies and supporting decisions to interdict the transport of nuclear material, we developed the Pathway Analysis, Threat Response and Interdiction Options Tool (PATRIOT) that provides an analytical approach for evaluating the probability that an adversary smuggling radioactive or special nuclear material will be detected during transit. We incorporate a global, multi-modal transportation network, explicit representation of designed and serendipitous detection opportunities, and multiple threat devices, material types, and shielding levels. This paper presents the general structure of PATRIOT, and focuses on the theoretical framework used to model the reliabilities of all network components that are used to predict the most likely pathways to the target.

  14. Modeling most likely pathways for smuggling radioactive and special nuclear materials on a worldwide multi-modal transportation network

    SciTech Connect (OSTI)

    Saeger, Kevin J [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory

    2010-10-28T23:59:59.000Z

    Nuclear weapons proliferation is an existing and growing worldwide problem. To help with devising strategies and supporting decisions to interdict the transport of nuclear material, we developed the Pathway Analysis, Threat Response and Interdiction Options Tool (PATRIOT) that provides an analytical approach for evaluating the probability that an adversary smuggling radioactive or special nuclear material will be detected during transit. We incorporate a global, multi-modal transportation network, explicit representation of designed and serendipitous detection opportunities, and multiple threat devices, material types, and shielding levels. This paper presents the general structure of PATRIOT, all focuses on the theoretical framework used to model the reliabilities of all network components that are used to predict the most likely pathways to the target.

  15. Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure

    SciTech Connect (OSTI)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28T23:59:59.000Z

    A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is {approx}37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

  16. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M [ORNL; Odbadrakh, Khorgolkhuu [ORNL; Rios, Orlando [ORNL; Hodges, Jason P [ORNL; Ludtka, Gerard Michael [ORNL; Porter, Wallace D [ORNL; Sefat, A. S. [Oak Ridge National Laboratory (ORNL); Rusanu, Aurelian [ORNL; Evans III, Boyd Mccutchen [ORNL

    2012-01-01T23:59:59.000Z

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system have been explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering (LSMS) method to explore the magnetic states responsible for the magnet-caloric effect in this material. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy were investigated using differential scanning calorimetry (DSC) and superconducting quantum interference device (SQUID). Neutron scattering experiments were performed to observe the structural and magnetic phase transformations at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on alloys of Ni-Mn-Ga and Ni-Mn-Ga-Cu-Fe. Data from the observations are discussed in comparison with the computational studies.

  17. Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials

    SciTech Connect (OSTI)

    Nicholson, Don M [ORNL; Odbadrakh, Khorgolkhuu [ORNL; Shassere, Benjamin [ORNL; Rios, Orlando [ORNL; Hodges, Jason P [ORNL; Ludtka, Gerard Michael [ORNL; Porter, Wallace D [ORNL; Safa-Sefat, Athena [ORNL; Rusanu, Aurelian [ORNL; Brown, Greg [ORNL; Evans III, Boyd Mccutchen [ORNL

    2014-01-01T23:59:59.000Z

    Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system are explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering method. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy are investigated using differential scanning calorimetry and superconducting quantum interference device. Experiments are performed at the Spallation Neutron Source at Oak Ridge National Laboratory to observe the structural and magnetic phase transformations.

  18. TREE FAILURES AND ACCIDENTS IN

    E-Print Network [OSTI]

    Standiford, Richard B.

    .DEPARTMENT O F AGRICULTURE GENERAL TECHNICAL REPORT PSW- 24 #12;TREE FAILURES AND ACCIDENTS IN RECREATION are major concerns. Injuries, fatalities, and high property losses occur each year as a result of tree losses associated with public occupancy. Hazard reduction can limit such losses to predefined levels

  19. Development of an atmospheric aerosol model for studies of global budgets and effects of airborne particulate material

    SciTech Connect (OSTI)

    Giorgi, F.

    1986-01-01T23:59:59.000Z

    A microphysics-removal Atmospheric Aerosol Model (AAM) is developed for use in General Circulation Models (GCM) to study global budgets and effects of particulate material. In this model the particle population is assumed to be composed of a set of log-normal modes whose time evolution due to microphysical processes is described via prognostic equations for an appropriate number of moments of the particle size distribution. This newly devised technique, by making use of a small number of prognostic equations for the aerosol variables and utilizing optimized numerical procedures, renders the model computationally efficient, hence particularly suitable for use in complex 3D GCMs. Detailed parameterizations of particle coagulation, sedimentation, dry deposition, and wet removal are incorporated into the AAM.

  20. Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds

    SciTech Connect (OSTI)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2007-01-01T23:59:59.000Z

    This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS). DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. The critical fusion zone sizes to ensure nugget pull-out failure mode are developed for both DP800 and TRIP800 using limit load based analytical model and micro-hardness measurements of the weld cross sections. Static weld strength tests using cross tension samples were performed on the joint populations with controlled fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 materials examined. The critical fusion zone size for nugget pullout shall be derived for individual materials based on different base metal properties as well as different heat affected zone (HAZ) and weld properties resulted from different welding parameters.

  1. MCWASP, Modeling of Casting, Welding and Advanced Solidification Processes XI TMS (The Minerals, Metals & Materials Society),

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    -COMPONENT ALLOYS USING LEVEL SET METHODS Nicholas Zabaras1 , Lijian Tan1 1 Materials Process Design and Control Laboratory 188 Frank H.T Rhodes Hall, Sibley school of Mechanical and Aerospace Engineering, Cornell, Multi-component alloy, Multi-phase, Fluid flow. Abstract A level set method combining features of front

  2. Critical Material Parameters for Modeling Devices Made from an Epoxy-Based Shape Memory Polymer

    E-Print Network [OSTI]

    Erel, Veysel

    2014-06-17T23:59:59.000Z

    sandwiched with a thermocouple between them, the temperature curve shows that 90 minutes is more than sufficient time to complete heat a single specimen to the test temperature............................ 45 ix 34 High temperature tensile test... for Testing and Materials DIC Digital Image Correlation DMA Dynamic Mechanical Analysis DSC Differential Scanning Calorimetry FEA Finite Element...

  3. Hydrogen Pipeline Material Testing We provide critical data, measurement methods and models that enable safe

    E-Print Network [OSTI]

    fatigue data for pipeline materials including steel alloys currently being used (API X52), those proposed helping to inform and revise relevant codes and standards. Impact and Customers While pipelines are the safest, most economical way to transport fuels, the pa- rameters used for codes and standards

  4. Derivation, Parameterization and Validation of a Sandy-Clay Material Model for Use

    E-Print Network [OSTI]

    Grujicic, Mica

    to provide the humanitarian relief in terms of medical services, safe drinking water, food, etc., is greatly divided into three main categories: (a) shock and blast wave mechanics/dynamics includ- ing landmine materials (high explosive, air, soil, etc.); (b) the kinematic and struc- tural response of the target

  5. Modeling the Dynamic Behavior of a Single Pile in Dry Sand using a new p-y Material Model

    E-Print Network [OSTI]

    Choi, JungIn; Brandenberg, Scott J; Kim, MyoungMo

    2013-01-01T23:59:59.000Z

    of dynamic pile behavior by centrifuge tests consideringof KOCED geotechnical centrifuge and its shear wave velocitysurface plasticity theory. Centrifuge model data analyzed

  6. Real-Time Quantitative Imaging of Failure Events in Materials...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Monday, 25 March 2013 00:00 Gathering information on the evolution of small cracks in ceramic matrix composites used in hostile environments such as in gas turbines and...

  7. Modeling Granular Materials as Compressible Non-Linear Fluids: Heat Transfer Boundary Value Problems

    SciTech Connect (OSTI)

    Massoudi, M.C.; Tran, P.X.

    2006-01-01T23:59:59.000Z

    We discuss three boundary value problems in the flow and heat transfer analysis in flowing granular materials: (i) the flow down an inclined plane with radiation effects at the free surface; (ii) the natural convection flow between two heated vertical walls; (iii) the shearing motion between two horizontal flat plates with heat conduction. It is assumed that the material behaves like a continuum, similar to a compressible nonlinear fluid where the effects of density gradients are incorporated in the stress tensor. For a fully developed flow the equations are simplified to a system of three nonlinear ordinary differential equations. The equations are made dimensionless and a parametric study is performed where the effects of various dimensionless numbers representing the effects of heat conduction, viscous dissipation, radiation, and so forth are presented.

  8. Modeling how cells move together could inspire self-healing materials...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    scientist mimicked the bumps on humpback whale fins to build more efficient wind turbine blades; Japanese engineers modeled the noses of bullet trains after kingfisher beaks,...

  9. Vehicle Technologies Office Merit Review 2014: Atomistic models of LMRNMC Materials

    Broader source: Energy.gov [DOE]

    Presentation given by Argonne National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about atomistic models...

  10. Model-Experimental Studies on Next-generation Li-ion Materials...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    D.C. es086srinivasan2010p.pdf More Documents & Publications Performance and Degradation Modeling of Batteries Improved Methods for Making Intermetallic Anodes Overview of...

  11. Unsteady-state material balance model for a continuous rotary dissolver

    SciTech Connect (OSTI)

    Lewis, B.E.

    1984-09-01T23:59:59.000Z

    The unsteady-state continuous rotary dissolver material balance code (USSCRD) is a useful tool with which to study the performance of the rotary dissolver under a wide variety of operating conditions. The code does stepwise continuous material balance calculations around each dissolver stage and the digester tanks. Output from the code consists of plots and tabular information on the stagewise concentration profiles of UO{sub 2}, PuO{sub 2}, fission products, Pu(NO{sub 3}){sub 4}, UO{sub 2}(NO{sub 3}){sub 2}, fission product nitrates, HNO{sub 3}, H{sub 2}O, stainless steel, total particulate, and total fuel in pins. Other information about material transfers, stagewise liquid volume, material inventory, and dissolution performance is also provided. This report describes the development of the code, its limitations, key operating parameters, usage procedures, and the results of the analysis of several sets of operating conditions. Of primary importance in this work was the estimation of the steady-state heavy metal inventory in a 0.5-t/d dissolver drum. Values ranging from {similar_to}12 to >150 kg of U + Pu were obtained for a variety of operating conditions. Realistically, inventories are expected to be near the lower end of this range. Study of the variation of operating parameters showed significant effects on dissolver product composition from intermittent solids feed. Other observations indicated that the cycle times for the digesters and shear feed should be closely coupled in order to avoid potential problems with off-specification product. 19 references, 14 tables.

  12. Porous Materials Porous Materials

    E-Print Network [OSTI]

    Berlin,Technische Universität

    1 Porous Materials x Porous Materials · Physical properties * Characteristic impedance p = p 0 e -jk xa- = vej[ ] p x - j ; Zc= p ve = c ka 0k = c 1-j #12;2 Porous Materials · Specific acoustic impedance Porous Materials · Finite thickness ­ blocked p e + -jk (x-d)a p e - jk (x-d)a d x #12

  13. Analytical modeling of elastic-plastic wave behavior near grain boundaries in crystalline materials

    SciTech Connect (OSTI)

    Loomis, Eric [Los Alamos National Laboratory; Greenfield, Scott [Los Alamos National Laboratory; Luo, Shengnian [Los Alamos National Laboratory; Swift, Damian [LLNL; Peralta, Pedro [ASU

    2009-01-01T23:59:59.000Z

    It is well known that changes in material properties across an interface will produce differences in the behavior of reflected and transmitted waves. This is seen frequently in planar impact experiments, and to a lesser extent, oblique impacts. In anisotropic elastic materials, wave behavior as a function of direction is usually accomplished with the aid of velocity surfaces, a graphical method for predicting wave scattering configurations. They have expanded this method to account for inelastic deformation due to crystal plasticity. The set of derived equations could not be put into a characteristic form, but instead led to an implicit problem. to overcome this difficulty an algorithm was developed to search the parameters space defined by a wave normal vector, particle velocity vector, and a wave speed. A solution was said to exist when a set from this parameter space satisfied the governing vector equation. Using this technique they can predict the anisotropic elastic-plastic velocity surfaces and grain boundary scattering configuration for crystalline materials undergoing deformation by slip. Specifically, they have calculated the configuration of scattered elastic-plastic waves in anisotropic NiAl for an incident compressional wave propagating along a <111> direction and contacting a 45 degree inclined grain boundary and found that large amplitude transmitted waves exist owing to the fact that the wave surface geometry forces it to propagate near the zero Schmid factor direction <100>.

  14. Development of an atmospheric aerosol model for studies of global budgets and effects of airborne particulate material

    SciTech Connect (OSTI)

    Giorgi, F.

    1986-01-01T23:59:59.000Z

    A microphysics-removal atmospheric aerosol model (AAM) is developed for use in general circulation models (GCMs) to study global budgets and effects of particulate material. In this model the particle population is composed of a set of log-normal modes whose time evolution due to microphysical processes is described via prognostic equations for an appropriate number of moments of the particle-size distribution. Detailed parameterizations of particle coagulation, sedimentation, dry deposition, and wet removal are developed and implemented into the AAM. The AAM is incorporated into a GCM and is applied to two types of studies: (1) characteristics of the particle wet and dry removal processes, and (2) climatic impact of massive particulate injections following a global nuclear war, with emphasis on the sensitivity of the simulated effects to the inclusion of particle microphysics. Results are discussed.

  15. Project Profile: Predictive Physico-Chemical Modeling of Intrinsic Degradation Mechanisms for Advanced Reflector Materials

    Broader source: Energy.gov [DOE]

    NREL, under the Physics of Reliability: Evaluating Design Insights for Component Technologies in Solar (PREDICTS) Program will be developing a physics-based computational degradation model to assess the kinetic oxidation rates; realistic model light attenuation and transport; and multi-layer treatment with variable properties Simulation based experimental design.

  16. Rheological constitutive equation for a model of soft glassy materials Peter Sollich*

    E-Print Network [OSTI]

    Sollich, Peter

    exactly and describe in detail a simplified scalar model for the low frequency shear rheology of foams, with a glass transition occurring at x 1 in appropriate units . The exact solution of the model takes the form 1 for 1 x 2, becoming flat near the glass transition. In the glass phase, aging of the moduli

  17. Optimization Online - Constraint Qualification Failure in Second ...

    E-Print Network [OSTI]

    Hassan L. Hijazi

    2014-07-22T23:59:59.000Z

    Jul 22, 2014 ... ... Qualification Failure in Second-Order Cone Formulations of Unbounded Disjunctions" Technical Report - NICTA, Canberra ACT Australia, ...

  18. Failure prognostic by using Dynamic Bayesian Networks

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to failures and their maintenance ex- pensive. To keep them in good operational conditions, maintenance to the ISO standard (ISO, 13381-1 (2004)), failure prognostic corresponds to the estimation of the operating presents a procedure for failure prognostic by using Dynamic Bayesian Networks (DBNs). The graphical

  19. GROUND PLANE INSULATION FAILURE IN THE FIRST TPC SUPERCONDUCTING COIL

    E-Print Network [OSTI]

    Green, M.A.

    2010-01-01T23:59:59.000Z

    is WIUUTEO GROUND PLANE INSULATION FAILURE IN THE FIRST TPCOn August 27, 1980, an insulation failure occurred dt-ringby a failure uf ground plane insulation. ACKNOWLEDGMENTS The

  20. Calibration of DEM models for granular materials using bulk physical tests 

    E-Print Network [OSTI]

    Johnstone, Mical William

    2010-01-01T23:59:59.000Z

    , when validation studies are conducted, discrepancies between bulk responses in physical tests and numerical predictions using measured particles properties may arise. The aire of this research is to develop a methodology to calibrate DEM models...

  1. Development of Apple Workgroup Cluster and Parallel Computing for Phase Field Model of Magnetic Materials

    E-Print Network [OSTI]

    Huang, Yongxin

    2010-01-16T23:59:59.000Z

    Micromagnetic modeling numerically solves magnetization evolution equation to process magnetic domain analysis, which helps to understand the macroscopic magnetic properties of ferromagnets. To apply this method in simulation of magnetostrictive...

  2. Improved model for the angular dependence of excimer laser ablation rates in polymer materials

    SciTech Connect (OSTI)

    Pedder, J. E. A.; Holmes, A. S. [Department of Electrical and Electronic Engineering, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Dyer, P. E. [Department of Physics, University of Hull, Hull HU6 7RX (United Kingdom)

    2009-10-26T23:59:59.000Z

    Measurements of the angle-dependent ablation rates of polymers that have applications in microdevice fabrication are reported. A simple model based on Beer's law, including plume absorption, is shown to give good agreement with the experimental findings for polycarbonate and SU8, ablated using the 193 and 248 nm excimer lasers, respectively. The modeling forms a useful tool for designing masks needed to fabricate complex surface relief by ablation.

  3. Micromechanical simulation of the failure of ber reinforced composites

    E-Print Network [OSTI]

    Micromechanical simulation of the failure of ®ber reinforced composites Chad M. Landisa, *, Irene J Abstract The strength of unidirectionally reinforced ®ber composites is simulated using the three lag model for broken ®bers in composites. J. Comp. Mat. 33, 667±680) and Weibull ®ber statistics

  4. Performance of Wireless Sensor Networks Under Random Node Failures

    E-Print Network [OSTI]

    Hagberg, Aric

    Performance of Wireless Sensor Networks Under Random Node Failures Milan Bradonji´c Bell range wireless sensor network applications with sensors distributed in the field using decentralized distribution. RGGs have been a standard tool to model and study wireless ad-hoc and wireless sensor networks [4

  5. A full-spectral Bayesian reconstruction approach based on the material decomposition model applied in dual-energy computed tomography

    SciTech Connect (OSTI)

    Cai, C. [CEA, LIST, 91191 Gif-sur-Yvette, France and CNRS, SUPELEC, UNIV PARIS SUD, L2S, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France)] [CEA, LIST, 91191 Gif-sur-Yvette, France and CNRS, SUPELEC, UNIV PARIS SUD, L2S, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France); Rodet, T.; Mohammad-Djafari, A. [CNRS, SUPELEC, UNIV PARIS SUD, L2S, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France)] [CNRS, SUPELEC, UNIV PARIS SUD, L2S, 3 rue Joliot-Curie, 91192 Gif-sur-Yvette (France); Legoupil, S. [CEA, LIST, 91191 Gif-sur-Yvette (France)] [CEA, LIST, 91191 Gif-sur-Yvette (France)

    2013-11-15T23:59:59.000Z

    Purpose: Dual-energy computed tomography (DECT) makes it possible to get two fractions of basis materials without segmentation. One is the soft-tissue equivalent water fraction and the other is the hard-matter equivalent bone fraction. Practical DECT measurements are usually obtained with polychromatic x-ray beams. Existing reconstruction approaches based on linear forward models without counting the beam polychromaticity fail to estimate the correct decomposition fractions and result in beam-hardening artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative-log preprocessing and the ill-conditioned water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on nonlinear forward models counting the beam polychromaticity show great potential for giving accurate fraction images.Methods: This work proposes a full-spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative-log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint maximum a posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a nonquadratic cost function. To solve it, the use of a monotone conjugate gradient algorithm with suboptimal descent steps is proposed.Results: The performance of the proposed approach is analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also necessary to have the accurate spectrum information about the source-detector system. When dealing with experimental data, the spectrum can be predicted by a Monte Carlo simulator. For the materials between water and bone, less than 5% separation errors are observed on the estimated decomposition fractions.Conclusions: The proposed approach is a statistical reconstruction approach based on a nonlinear forward model counting the full beam polychromaticity and applied directly to the projections without taking negative-log. Compared to the approaches based on linear forward models and the BHA correction approaches, it has advantages in noise robustness and reconstruction accuracy.

  6. Power Grid Defense Against Malicious Cascading Failure

    E-Print Network [OSTI]

    Shakarian, Paulo; Lindelauf, Roy

    2014-01-01T23:59:59.000Z

    An adversary looking to disrupt a power grid may look to target certain substations and sources of power generation to initiate a cascading failure that maximizes the number of customers without electricity. This is particularly an important concern when the enemy has the capability to launch cyber-attacks as practical concerns (i.e. avoiding disruption of service, presence of legacy systems, etc.) may hinder security. Hence, a defender can harden the security posture at certain power stations but may lack the time and resources to do this for the entire power grid. We model a power grid as a graph and introduce the cascading failure game in which both the defender and attacker choose a subset of power stations such as to minimize (maximize) the number of consumers having access to producers of power. We formalize problems for identifying both mixed and deterministic strategies for both players, prove complexity results under a variety of different scenarios, identify tractable cases, and develop algorithms f...

  7. A stochastic flow rule for granular materials

    E-Print Network [OSTI]

    Ken Kamrin; Martin Z. Bazant

    2006-09-19T23:59:59.000Z

    There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-2D granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account two crucial features of granular materials - discreteness and randomness - via diffusing "spots" of local fluidization, which act as carriers of plasticity. We postulate that spots perform random walks biased along slip-lines with a drift direction determined by the stress imbalance upon a local switch from static to dynamic friction. In the continuum limit (based on a Fokker-Planck equation for the spot concentration), this simple model is able to predict a variety of granular flow profiles in flat-bottom silos, annular Couette cells, flowing heaps, and plate-dragging experiments -- with essentially no fitting parameters -- although it is only expected to function where material is at incipient failure and slip-lines are inadmissible. For special cases of admissible slip-lines, such as plate dragging under a heavy load or flow down an inclined plane, we postulate a transition to rate-dependent Bagnold rheology, where flow occurs by sliding shear planes. With different yield criteria, the SFR provides a general framework for multiscale modeling of plasticity in amorphous materials, cycling between continuum limit-state stress calculations, meso-scale spot random walks, and microscopic particle relaxation.

  8. RELAP5 Model of a Two-phase ThermoSyphon Experimental Facility for Fuels and Materials Irradiation

    SciTech Connect (OSTI)

    Carbajo, Juan J [ORNL] [ORNL; McDuffee, Joel Lee [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) does not have a separate materials-irradiation flow loop and requires most materials and all fuel experiments to be placed inside a containment. This is necessary to ensure that internal contaminants such as fission products cannot be released into the primary coolant. As part of the safety basis justification, HFIR also requires that all experiments be able to withstand various accident conditions (e.g., loss of coolant) without generating vapor bubbles on the surface of the experiment in the primary coolant. As with any parallel flow system, HFIR is vulnerable to flow excursion events when vapor is generated in one of those flow paths. The effects of these requirements are to artificially increase experiment temperatures by introducing a barrier between the experimental materials and the HFIR coolant and to reduce experiment heat loads to ensure boiling doesn t occur. A new experimental facility for materials irradiation and testing in the HFIR is currently being developed to overcome these limitations. The new facility is unique in that it will have its own internal cooling flow totally independent of the reactor primary coolant and boiling is permitted. The reactor primary coolant will cool the outside of this facility without contacting the materials inside. The ThermoSyphon Test Loop (TSTL), a full scale prototype of the proposed irradiation facility to be tested outside the reactor, is being designed and fabricated (Ref. 1). The TSTL is a closed system working as a two-phase thermosyphon. A schematic is shown in Fig. 1. The bottom central part is the boiler/evaporator and contains three electric heaters. The vapor generated by the heaters will rise and be condensed in the upper condenser, the condensate will drain down the side walls and be circulated via a downcomer back into the bottom of the boiler. An external flow system provides coolant that simulates the HFIR primary coolant. The two-phase flow code RELAP5-3D (Ref. 2) is the main tool employed in this design. The model has multiple challenges: boiling, condensation and natural convection flows need to be modeled accurately.

  9. Global Failure Criteria for SOFC Positive/Electrolyte/Negative (PEN) Structure

    SciTech Connect (OSTI)

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Qu, Jianmin

    2007-04-01T23:59:59.000Z

    Due to the mismatch of thermal expansion coefficients (TEC) of the various layer materials in SOFC, the internal stresses are unavoidable under temperature differential. In order to create the reliable cell and stack of solid oxide fuel cell (SOFC), it is necessary to develop a failure criterion for SOFC PEN structures for the initial failures occurred during cell/stack assembly. In this paper, a global failure criterion is developed for the initial design against mechanical failure of the PEN structure in high temperature SOFCs. The relationship of the critical energy release rate and critical curvature and maximum displacement of the warpage of the cells caused by the temperature differential is established so that the failure reliability of SOFC PEN structures may be determined by the measurement of the curvature and displacement of the warpaged cells.

  10. Original article Increased late sodium current in myocytes from a canine heart failure

    E-Print Network [OSTI]

    Kamp, Tim

    Original article Increased late sodium current in myocytes from a canine heart failure model and from failing human heart Carmen R. Valdivia, William W. Chu, Jielin Pu 1 , Jason D. Foell, Robert A December 2004 Abstract Electrophysiological remodeling of ion channels in heart failure causes action

  11. Correlated Failures of Power Systems: The Analysis of the Nordic Grid

    E-Print Network [OSTI]

    Johansson, Karl Henrik

    Correlated Failures of Power Systems: The Analysis of the Nordic Grid M. Andreasson, S. Amin, G the effects of correlations between failures of power lines on the total system load shed. The total system on the sampling accuracy. This framework has been applied to a 470 bus model of the Nordic power system

  12. An Automatic Failure Mode and Effect Analysis Technique for Processes Defined in the Little-JIL

    E-Print Network [OSTI]

    Avrunin, George S.

    Failure Mode and Effect Analysis (FMEA) information from processes modeled in the Little-JIL process definition language. Typically FMEA information is created manually by skilled experts, an approach this definition can then be used to create FMEA representations for a wide range of potential failures

  13. Solar Energy Materials & Solar Cells 92 (2008) 821829 Modeling the optical properties of WO3 and WO3SiO2 thin films

    E-Print Network [OSTI]

    Thirumalai, Devarajan

    Solar Energy Materials & Solar Cells 92 (2008) 821­829 Modeling the optical properties of WO3 the optical response of the films in the near-UV and visible region: two interband transitions for energies E

  14. Nonlinear Rate-Dependent Material Model with Damage and Plasticity from Granular Micromechanics Approach

    E-Print Network [OSTI]

    Singh, Viraj

    2014-05-31T23:59:59.000Z

    are defined using simple 1d functions at micro-scale. To demonstrate the capability of the developed model, it is implemented into a finite element and Euler beam framework to predict, (a) the nonlinear bending of dentin adhesive and collagen...

  15. Modeling the essential atomistic influence in the phase transformation dynamics of shape memory materials

    E-Print Network [OSTI]

    Melnik, Roderick

    Modeling the essential atomistic influence in the phase transformation dynamics of shape memory of multivariant phase transformation in shape memory alloy has been developed. This paper is focused on linking Shape memory effects in alloys are observed due to the existence of large differences in the variants

  16. The Transition-Zone Water Filter Model for Global Material Circulation: Where Do We Stand?

    E-Print Network [OSTI]

    with a small melt fraction, highly incompatible elements including hydro- gen, helium and argon are sequestered the fraction of water is small. Models have been developed to understand the structure of a melt layer Hilst, et al., 1997]), then the whole mantle is depleted with only a small volume (~10%) of relatively

  17. Modeling of the Properties and Processing of Amorphous Gate Stacks on High Electron Mobility Materials

    E-Print Network [OSTI]

    Kummel, Andrew C.

    of their defects, simply do not exist. Further, there are no techniques which give the precise bonding structure diffusion of the semiconductor into the oxide? The role of the passivation layer is a key issue which/oxide interfaces and minimize diffusion into the oxide? d. Can we model the C-V and phonon coupling as a function

  18. Stationary shear ows of dense granular materials : a tentative continuum modelling

    E-Print Network [OSTI]

    -less granular media. Compressibil- ity, dilatancy and Coulomb-like friction are the three basic ingredients Abstract We propose a simple continuum model to interpret the shearing motion of dense, dry and cohesion slow motions with predominance of friction, less dense ones are usually found in vigorous motions

  19. Thermo-Viscoelastic-Viscoplastic-Viscodamage-Healing Modeling of Bituminous Materials: Theory and Computation

    E-Print Network [OSTI]

    Darabi Konartakhteh, Masoud

    2012-10-19T23:59:59.000Z

    ……………… ……… 341 9.6. Extrapolation of the Rutting in 3D.……....………… 348 9.7. Comparison with Experimental Results.….………… 351 9.8. Conclusions………………………………………… 354 xviii CHAPTER Page X CONCLUSIONS AND RECOMMENDATIONS..…………… 356 10... prediction using viscoelastic- viscoplastic model and experimental data for the cyclic stress control test at 19oC when the stress amplitude is 750kPa. (a) Loading cycles 1-30; (b) Loading cycles 970-980……………….. 268 7.36 Comparison of the VE...

  20. Continuum limits of bistable spring models of carbon nanotube arrays accounting for material damage

    E-Print Network [OSTI]

    T. Blesgen; F. Fraternali; J. R. Raney; A. Amendola; C. Daraio

    2011-12-10T23:59:59.000Z

    Using chains of bistable springs, a model is derived to investigate the plastic behavior of carbon nanotube arrays with damage. We study the preconditioning effect due to the loading history by computing analytically the stress-strain pattern corresponding to a fatigue-type damage of the structure. We identify the convergence of the discrete response to the limiting case of infinitely many springs, both analytically in the framework of Gamma-convergence, as well as numerically.

  1. Contact method to allow benign failure in ceramic capacitor having self-clearing feature

    DOE Patents [OSTI]

    Myers, John D.; Taylor, Ralph S.

    2012-06-26T23:59:59.000Z

    A capacitor exhibiting a benign failure mode has a first electrode layer, a first ceramic dielectric layer deposited on a surface of the first electrode, and a second electrode layer disposed on the ceramic dielectric layer, wherein selected areas of the ceramic dielectric layer have additional dielectric material of sufficient thickness to exhibit a higher dielectric breakdown voltage than the remaining majority of the dielectric layer. The added thickness of the dielectric layer in selected areas allows lead connections to be made at the selected areas of greater dielectric thickness while substantially eliminating a risk of dielectric breakdown and failure at the lead connections, whereby the benign failure mode is preserved.

  2. Velocity models, material balance and solution convergence in streamline-based simulation

    E-Print Network [OSTI]

    Sabir, Kamran

    2002-01-01T23:59:59.000Z

    of {x, y, z) to a unit cube in the pseudo space of (a, P, y). This code also determines the velocity models, and sketches the streamlines in the domain. Calculation of time of flight is also incorporated in the code. Another code was written... be obtained from the velocity components. 2. 2 Five-Spot Waterflooding Pattern Morel-Seytoux shows that the following are the potential (P) and stream (r[r) functions for five-spot waterflooding pattern (quarter five-spot symmetry element): ] 1 ? rn[4x...

  3. Clinical Outcomes and Patterns of Failure After Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma

    SciTech Connect (OSTI)

    Ng, Wai Tong, E-mail: ngwt1@ha.org.h [Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital (Hong Kong); Lee, Michael C.H. [Department of Medical Physics, Pamela Youde Nethersole Eastern Hospital (Hong Kong); Hung, Wai Man; Choi, Cheuk Wai; Lee, Kin Chung; Chan, Oscar S.H.; Lee, Anne W.M. [Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital (Hong Kong)

    2011-02-01T23:59:59.000Z

    Purpose: To study and report the clinical outcomes and patterns of failure after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Methods and Materials: The treatment outcomes of NPC patients treated with IMRT at Pamela Youde Nethersole Eastern Hospital between 2005 and 2007 were reviewed. The location and extent of locoregional failures were transferred to the pretreatment planning computed tomography for dosimetry analysis. Statistical analyses were performed on dose coverage and locoregional failures. Results: A total of 193 NPC patients were analyzed; 93% had Stage III/IV disease. Median follow-up was 30 months. Overall disease failure (at any site) developed in 35 patients. Among these, there were 23 distant metastases, 16 local failures, and 9 regional failures. Four of the locoregional failures were marginal. Dose conformity with IMRT was excellent. Patients with at least 66.5 Gy to their target volumes had significantly less locoregional failure. The 2-year local progression-free, regional progression-free, distant metastasis-free, and overall survival rates were 95%, 96%, 90%, and 92%, respectively. Conclusions: Intensity-modulated radiotherapy provides excellent locoregional control for NPC. Distant metastasis remains the most difficult challenge, and more effective systemic agents should be explored for patients presenting with advanced locoregional diseases.

  4. Modeling of material and energy flow in an EBCHR casting system

    SciTech Connect (OSTI)

    Westerberg, K.W. [Aspen Technology, Inc., Cambridge, MA (United States); McClelland, M.A. [Lawrence Livermore National Lab., CA (United States)

    1994-11-01T23:59:59.000Z

    A numerical and experimental analysis is made of fluid flow and heat transfer in a continuous casting system with an electron-beam energy source. For a cylindrical ingot confined in a water-cooled crucible, a two-dimensional, steady-state model is developed which includes the effects of free convection in the pool and conduction in the two-phase and solid regions. A modified Galerkin finite element method is used to solve for the flow and temperature fields simultaneously with the upper and lower boundaries of the pool. The calculation grid deforms along vertical spines as these phase boundaries move. Heat flows are measured in a steady-state experiment involving a short ingot and no pouring. Heat transfer coefficients representing contact resistance are determined, and measured heat flows are compared with model values. Flow and temperature fields along with solidification-zone boundaries are calculated for the experimental case and a case in which the ingot cooling is improved.

  5. Modeling of material and energy flow in an EBCHR casting system

    SciTech Connect (OSTI)

    Westerberg, K.W. [Aspen Technology, Inc., Cambridge, MA (United States); McClelland, M.A. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31T23:59:59.000Z

    A numerical and experimental analysis is made of fluid flow and heat transfer in a continuous casting system with an electron-beam energy source. For a cylindrical ingot confined in a water-cooled crucible, a two-dimensional, steady-state model is developed which includes the effects of free convection in the pool and conduction in the two-phase and solid regions. A modified Galerkin finite element method is used to solve for the flow and temperature fields simultaneously with the upper and lower boundaries of the pool. The calculation grid deforms along vertical spines as these phase boundaries move. Heat flows are measured in a steady-state experiment involving a short ingot and no pouring. Heat transfer coefficients representing contact resistance are determined, and measured heat flows are compared with model values. Flow and temperature fields along with solidification-zone boundaries are calculated for the experimental case and a case in which the ingot cooling is improved.

  6. Modeling of the Terminal Velocities of the Dust Ejected Material by the Impact

    E-Print Network [OSTI]

    M. Rengel; M. Kueppers; H. U. Keller; P. Gutierrez

    2007-01-03T23:59:59.000Z

    We compute the distribution of velocities of the particles ejected by the impact of the projectile released from NASA Deep Impact spacecraft on the nucleus of comet 9P/Tempel 1 on the successive 20 hours following the collision. This is performed by the development and use of an ill-conditioned inverse problem approach, whose main ingredients are a set of observations taken by the Narrow Angle Camera (NAC) of OSIRIS onboard the Rosetta spacecraft, and a set of simple models of the expansion of the dust ejecta plume for different velocities. Terminal velocities are derived using a maximum likelihood estimator. We compare our results with published estimates of the expansion velocity of the dust cloud. Our approach and models reproduce well the velocity distribution of the ejected particles. We consider these successful comparisons of the velocities as an evidence for the appropriateness of the approach. This analysis provides a more thorough understanding of the properties of the Deep Impact dust cloud.

  7. Failure analysis issues in microelectromechanical systems (MEMS).

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen

    2005-07-01T23:59:59.000Z

    Failure analysis and device characterization of MEMS components are critical steps in understanding the root causes of failure and improving device performance. At the wafer and die level these tasks can be performed with little or no sample preparation. Larger challenges occur after fabrication when the device is packaged, capped, sealed, or otherwise obstructed from view. The challenges and issues of MEMS failure analysis lie in identifying the root cause of failure for these packaged, capped, and sealed devices without perturbing the device or its immediate environment. Novel methods of gaining access to the device or preparing the device for analysis are crucial to accurately determining the root cause of failure. This paper will discuss issues identified in performing root cause failure analysis of packaged MEMS devices, as well as the methods employed to analyze them.

  8. Theoretical Modelling of Magnetic Refrigeration Materials A PhD studentship is available in the Warwick Theory Group on a theoretical/computational PhD project

    E-Print Network [OSTI]

    Low, Robert

    Theoretical Modelling of Magnetic Refrigeration Materials A PhD studentship is available in the Warwick Theory Group on a theoretical/computational PhD project on the modelling of magnetic refrigeration or air, or for very low temperatures, helium. Therefore, magnetic refrigeration is environmentally

  9. Summary of failure analysis activities at Brookhaven National Laboratory

    SciTech Connect (OSTI)

    Cowgill, M.G.; Czajkowski, C.J.; Franz, E.M.

    1996-10-01T23:59:59.000Z

    Brookhaven National Laboratory has for many years conducted examinations related to the failures of nuclear materials and components. These examinations included the confirmation of root cause analyses, the determination of the causes of failure, identification of the species that accelerate corrosion, and comparison of the results of nondestructive examinations with those obtained by destructive examination. The results of those examinations, which had previously appeared in various formats (formal and informal reports, journal articles, etc.), have been collected together and summarized in the present report. The report is divided into sections according to the general subject matter (for example, corrosion, fatigue, etc.). Each section presents summaries of the information contained in specific reports and publications, all of which are fully identified as to title, authors, report number or journal reference, date of publication, and FIN number under which the work was performed.

  10. Thermal performance sensitivity studies in support of material modeling for extended storage of used nuclear fuel

    SciTech Connect (OSTI)

    Cuta, Judith M.; Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.

    2013-08-15T23:59:59.000Z

    The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

  11. Addressing failures in exascale computing

    SciTech Connect (OSTI)

    Snir, Marc; Wisniewski, Robert W.; Abraham, Jacob A.; Adve, Sarita; Bagchi, Saurabh; Balaji, Pavan; Belak, Jim; Bose, Pradip; Cappello, Franck; Carlson, William; Chien, Andrew A.; Coteus, Paul; Debardeleben, Nathan A.; Diniz, Pedro; Engelmann, Christian; Erez, Mattan; Saverio, Fazzari; Geist, Al; Gupta, Rinku; Johnson, Fred; Krishnamoorthy, Sriram; Leyffer, Sven; Liberty, Dean; Mitra, Subhasish; Munson, Todd; Schreiber, Robert; Stearly, Jon; Van Hensbergen, Eric

    2014-05-01T23:59:59.000Z

    We present here a report produced by a workshop on “Addressing Failures in Exascale Computing” held in Park City, Utah, August 4–11, 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system; discuss existing knowledge on resilience across the various hardware and software layers of an exascale system; and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia; and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  12. Addressing Failures in Exascale Computing

    SciTech Connect (OSTI)

    Snir, Marc [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Wisniewski, Robert [Intel Corporation] [Intel Corporation; Abraham, Jacob [unknown] [unknown; Adve, Sarita [University of Illinois, Urbana-Champaign] [University of Illinois, Urbana-Champaign; Bagchi, Saurabh [Purdue University] [Purdue University; Balaji, Pavan [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Belak, J. [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Bose, Pradip [IBM T. J. Watson Research Center] [IBM T. J. Watson Research Center; Cappello, Franck [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Carlson, Bill [unknown] [unknown; Chien, Andrew [University of Chicago] [University of Chicago; Coteus, Paul [IBM T. J. Watson Research Center] [IBM T. J. Watson Research Center; DeBardeleben, Nathan [Los Alamos National Laboratory (LANL)] [Los Alamos National Laboratory (LANL); Diniz, Pedro [University of Southern California] [University of Southern California; Engelmann, Christian [ORNL] [ORNL; Erez, Mattan [University of Texas at Austin] [University of Texas at Austin; Fazzari, Saverio [Booz Allen Hamilton] [Booz Allen Hamilton; Geist, Al [ORNL] [ORNL; Gupta, Rinku [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Johnson, Fred [Science Applications International Corporation (SAIC), Oak Ridge, TN] [Science Applications International Corporation (SAIC), Oak Ridge, TN; Krishnamoorthy, Sriram [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Leyffer, Sven [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Liberty, Dean [AMD] [AMD; Mitra, Subhasish [Stanford University] [Stanford University; Munson, Todd [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Schreiber, Rob [HP Labs] [HP Labs; Stearley, Jon [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Van Hensbergen, Eric [ARM] [ARM

    2014-01-01T23:59:59.000Z

    We present here a report produced by a workshop on Addressing failures in exascale computing' held in Park City, Utah, 4-11 August 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system, discuss existing knowledge on resilience across the various hardware and software layers of an exascale system, and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia, and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  13. RESRAD-BUILD: A computer model for analyzing the radiological doses resulting from the remediation and occupancy of buildings contaminated with radioactive material

    SciTech Connect (OSTI)

    Yu, C.; LePoire, D.J.; Jones, L.G. [and others

    1994-11-01T23:59:59.000Z

    The RESRAD-BUILD computer code is a pathway analysis model designed to evaluate the potential radiological dose incurred by an individual who works or lives in a building contaminated with radioactive material. The transport of radioactive material inside the building from one compartment to another is calculated with an indoor air quality model. The air quality model considers the transport of radioactive dust particulates and radon progeny due to air exchange, deposition and resuspension, and radioactive decay and ingrowth. A single run of the RESRAD-BUILD code can model a building with up to: three compartments, 10 distinct source geometries, and 10 receptor locations. A shielding material can be specified between each source-receptor pair for external gamma dose calculations. Six exposure pathways are considered in the RESRAD-BUILD code: (1) external exposure directly from the source; (2) external exposure to materials deposited on the floor; (3) external exposure due to air submersion; (4) inhalation of airborne radioactive particulates; (5) inhalation of aerosol indoor radon progeny; and (6) inadvertent ingestion of radioactive material, either directly from the sources or from materials deposited on the surfaces of the building compartments. 4 refs., 23 figs., 4 tabs.

  14. Identification and Assessment of Material Models for Age-Related Degradation of Structures and Passive Components in Nuclear Power Plants

    SciTech Connect (OSTI)

    Nie,J.; Braverman, J.; Hofmayer, C.; Kim, M. K.; Choi, I-K.

    2009-04-27T23:59:59.000Z

    When performing seismic safety assessments of nuclear power plants (NPPs), the potential effects of age-related degradation on structures, systems, and components (SSCs) should be considered. To address the issue of aging degradation, the Korea Atomic Energy Research Institute (KAERI) has embarked on a five-year research project to develop a realistic seismic risk evaluation system which will include the consideration of aging of structures and components in NPPs. Three specific areas that are included in the KAERI research project, related to seismic probabilistic risk assessment (PRA), are probabilistic seismic hazard analysis, seismic fragility analysis including the effects of aging, and a plant seismic risk analysis. To support the development of seismic capability evaluation technology for degraded structures and components, KAERI entered into a collaboration agreement with Brookhaven National Laboratory (BNL) in 2007. The collaborative research effort is intended to continue over a five year period with the goal of developing seismic fragility analysis methods that consider the potential effects of age-related degradation of SSCs, and using these results as input to seismic PRAs. In the Year 1 scope of work BNL collected and reviewed degradation occurrences in US NPPs and identified important aging characteristics needed for the seismic capability evaluations that will be performed in the subsequent evaluations in the years that follow. This information is presented in the Annual Report for the Year 1 Task, identified as BNL Report-81741-2008 and also designated as KAERI/RR-2931/2008. The report presents results of the statistical and trending analysis of this data and compares the results to prior aging studies. In addition, the report provides a description of U.S. current regulatory requirements, regulatory guidance documents, generic communications, industry standards and guidance, and past research related to aging degradation of SSCs. This report describes the research effort performed by BNL for the Year 2 scope of work. This research focused on methods that could be used to represent the long-term behavior of materials used at NPPs. To achieve this BNL reviewed time-dependent models which can approximate the degradation effects of the key materials used in the construction of structures and passive components determined to be of interest in the Year 1 effort. The intent was to review the degradation models that would cover the most common time-dependent changes in material properties for concrete and steel components.

  15. The Impact of Protection System Failures on Power System Reliability Evaluation

    E-Print Network [OSTI]

    Jiang, Kai

    2012-11-05T23:59:59.000Z

    The reliability of protection systems has emerged as an important topic because protection failures have critical influence on the reliability of power systems. The goal of this research is to develop novel approaches for modeling and analysis...

  16. Probabilistic Hazard Assessment of Tsunamis Induced by the Translational Failure of Multiple Submarine Rigid Landslides

    E-Print Network [OSTI]

    Jimenez Martinez, Arturo

    2012-10-19T23:59:59.000Z

    A numerical study aimed at probabilistically assessing the coastal hazard posed by tsunamis induced by one-dimensional submarine rigid landslides that experience translational failure is presented. The numerical model here utilized is the finite...

  17. OPERATING EXPERIENCE LEVEL 3, Requalification Test Failure of Certain High Efficiency Particulate Air (HEPA) Filters- Update

    Broader source: Energy.gov [DOE]

    Operating Experience Level 3 (OE-3) document provides information regarding the previous requalification test failure and subsequent successful requalification, of certain high efficiency particulate air (HEPA) filter models manufactured by Flanders Corporation.

  18. Nuclear Engineering and Design 236 (2006) 16411647 Basic factors to forecast maintenance cost and failure processes for

    E-Print Network [OSTI]

    Popova, Elmira

    2006-01-01T23:59:59.000Z

    . The importance of equipment reliability and prediction in the commercial nuclear power plant is presented along a Bayesian model for the failure rate of the equipment, which is input to the cost forecasting model Texas Project Nuclear Operating Company (STPNOC): failure times, repair costs, equipment downtime

  19. Module Design, Materials, and Packaging Research Team: Activities and Capabilities

    SciTech Connect (OSTI)

    McMahon, T. J.; del Cueto, J.; Glick, S.; Jorgensen, G.; Kempe, M.; Kennedy, C.; Pern, J.; Terwilliger, K

    2005-01-01T23:59:59.000Z

    Our team activities are directed at improving PV module reliability by incorporating new, more effective, and less expensive packaging materials and techniques. New and existing materials or designs are evaluated before and during accelerated environmental exposure for the following properties: (1) Adhesion and cohesion: peel strength and lap shear. (2) Electrical conductivity: surface, bulk, interface and transients. (3) Water vapor transmission: solubility and diffusivity. (4) Accelerated weathering: ultraviolet, temperature, and damp heat tests. (5) Module and cell failure diagnostics: infrared imaging, individual cell shunt characterization, coring. (6) Fabrication improvements: SiOxNy barrier coatings and enhanced wet adhesion. (7) Numerical modeling: Moisture ingress/egress, module and cell performance, and cell-to-frame leakage current. (8) Rheological properties of polymer encapsulant and sheeting materials. Specific examples will be described.

  20. Progress in Developing Finite Element Models Replicating Flexural Graphite Testing

    SciTech Connect (OSTI)

    Robert Bratton

    2010-06-01T23:59:59.000Z

    This report documents the status of flexural strength evaluations from current ASTM procedures and of developing finite element models predicting the probability of failure. This work is covered under QLD REC-00030. Flexural testing procedures of the American Society for Testing and Materials (ASTM) assume a linear elastic material that has the same moduli for tension and compression. Contrary to this assumption, graphite is known to have different moduli for tension and compression. A finite element model was developed and demonstrated that accounts for the difference in moduli tension and compression. Brittle materials such as graphite exhibit significant scatter in tensile strength, so probabilistic design approaches must be used when designing components fabricated from brittle materials. ASTM procedures predicting probability of failure in ceramics were compared to methods from the current version of the ASME graphite core components rules predicting probability of failure. Using the ASTM procedures yields failure curves at lower applied forces than the ASME rules. A journal paper was published in the Journal of Nuclear Engineering and Design exploring the statistical models of fracture in graphite.

  1. WAXS fat subtraction model to estimate differential linear scattering coefficients of fatless breast tissue: Phantom materials evaluation

    SciTech Connect (OSTI)

    Tang, Robert Y., E-mail: rx-tang@laurentian.ca [Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); Laamanen, Curtis, E-mail: cx-laamanen@laurentian.ca; McDonald, Nancy, E-mail: mcdnancye@gmail.com [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada)] [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); LeClair, Robert J., E-mail: rleclair@laurentian.ca [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada)

    2014-05-15T23:59:59.000Z

    Purpose: Develop a method to subtract fat tissue contributions to wide-angle x-ray scatter (WAXS) signals of breast biopsies in order to estimate the differential linear scattering coefficients ?{sub s} of fatless tissue. Cancerous and fibroglandular tissue can then be compared independent of fat content. In this work phantom materials with known compositions were used to test the efficacy of the WAXS subtraction model. Methods: Each sample 5 mm in diameter and 5 mm thick was interrogated by a 50 kV 2.7 mm diameter beam for 3 min. A 25 mm{sup 2} by 1 mm thick CdTe detector allowed measurements of a portion of the ? = 6° scattered field. A scatter technique provided means to estimate the incident spectrum N{sub 0}(E) needed in the calculations of ?{sub s}[x(E, ?)] where x is the momentum transfer argument. Values of ?{sup ¯}{sub s} for composite phantoms consisting of three plastic layers were estimated and compared to the values obtained via the sum ?{sup ¯}{sub s}{sup ?}(x)=?{sub 1}?{sub s1}(x)+?{sub 2}?{sub s2}(x)+?{sub 3}?{sub s3}(x), where ?{sub i} is the fractional volume of the ith plastic component. Water, polystyrene, and a volume mixture of 0.6 water + 0.4 polystyrene labelled as fibphan were chosen to mimic cancer, fat, and fibroglandular tissue, respectively. A WAXS subtraction model was used to remove the polystyrene signal from tissue composite phantoms so that the ?{sub s} of water and fibphan could be estimated. Although the composite samples were layered, simulations were performed to test the models under nonlayered conditions. Results: The well known ?{sub s} signal of water was reproduced effectively between 0.5 < x < 1.6 nm{sup ?1}. The ?{sup ¯}{sub s} obtained for the heterogeneous samples agreed with ?{sup ¯}{sub s}{sup ?}. Polystyrene signals were subtracted successfully from composite phantoms. The simulations validated the usefulness of the WAXS models for nonlayered biopsies. Conclusions: The methodology to measure ?{sub s} of homogeneous samples was quantitatively accurate. Simple WAXS models predicted the probabilities for specific x-ray scattering to occur from heterogeneous biopsies. The fat subtraction model can allow ?{sub s} signals of breast cancer and fibroglandular tissue to be compared without the effects of fat provided there is an independent measurement of the fat volume fraction ?{sub f}. Future work will consist of devising a quantitative x-ray digital imaging method to estimate ?{sub f} in ex vivo breast samples.

  2. MEMS Reliability: Infrastructure, Test Structures, Experiments, and Failure Modes

    SciTech Connect (OSTI)

    TANNER,DANELLE M.; SMITH,NORMAN F.; IRWIN,LLOYD W.; EATON,WILLIAM P.; HELGESEN,KAREN SUE; CLEMENT,J. JOSEPH; MILLER,WILLIAM M.; MILLER,SAMUEL L.; DUGGER,MICHAEL T.; WALRAVEN,JEREMY A.; PETERSON,KENNETH A.

    2000-01-01T23:59:59.000Z

    The burgeoning new technology of Micro-Electro-Mechanical Systems (MEMS) shows great promise in the weapons arena. We can now conceive of micro-gyros, micro-surety systems, and micro-navigators that are extremely small and inexpensive. Do we want to use this new technology in critical applications such as nuclear weapons? This question drove us to understand the reliability and failure mechanisms of silicon surface-micromachined MEMS. Development of a testing infrastructure was a crucial step to perform reliability experiments on MEMS devices and will be reported here. In addition, reliability test structures have been designed and characterized. Many experiments were performed to investigate failure modes and specifically those in different environments (humidity, temperature, shock, vibration, and storage). A predictive reliability model for wear of rubbing surfaces in microengines was developed. The root causes of failure for operating and non-operating MEMS are discussed. The major failure mechanism for operating MEMS was wear of the polysilicon rubbing surfaces. Reliability design rules for future MEMS devices are established.

  3. CLINICAL RESEARCH Heart failure/cardiomyopathy

    E-Print Network [OSTI]

    Duncan, James S.

    RESEARCH Heart failure/cardiomyopathy Preserved left ventricular twist and circumferential deformation, but depressed longitudinal and radial deformation in patients with diastolic heart failure Jianwen Wang, Dirar SBakey Heart Center, The Methodist Hospital, Houston, TX 77030-2717, USA Received 27 September 2007; revised 15

  4. Analyzing Cascading Failures in Smart Grids under Random and Targeted Attacks

    E-Print Network [OSTI]

    Ruj, Sushmita

    2015-01-01T23:59:59.000Z

    We model smart grids as complex interdependent networks, and study targeted attacks on smart grids for the first time. A smart grid consists of two networks: the power network and the communication network, interconnected by edges. Occurrence of failures (attacks) in one network triggers failures in the other network, and propagates in cascades across the networks. Such cascading failures can result in disintegration of either (or both) of the networks. Earlier works considered only random failures. In practical situations, an attacker is more likely to compromise nodes selectively. We study cascading failures in smart grids, where an attacker selectively compromises the nodes with probabilities proportional to their degrees; high degree nodes are compromised with higher probability. We mathematically analyze the sizes of the giant components of the networks under targeted attacks, and compare the results with the corresponding sizes under random attacks. We show that networks disintegrate faster for targeted...

  5. A novel approach to integrating design into manufacturing and materials education through the fabrication of a scale model cannon 

    E-Print Network [OSTI]

    Weinstein, Jeremy L.

    2004-09-30T23:59:59.000Z

    . Selected materials were then subjected to heat treatment. Once the material processing was complete; Manual Machining, CNC Machining, Welding and a novel Rapid Manufacturing approach were used to produce the cannons. The cannons were then tested...

  6. DEVELOPMENT OF PLASTICITY MODEL USING NON ASSOCIATED FLOW RULE FOR HCP MATERIALS INCLUDING ZIRCONIUM FOR NUCLEAR APPLICATIONS

    SciTech Connect (OSTI)

    Michael V. Glazoff; Jeong-Whan Yoon

    2013-08-01T23:59:59.000Z

    In this report (prepared in collaboration with Prof. Jeong Whan Yoon, Deakin University, Melbourne, Australia) a research effort was made to develop a non associated flow rule for zirconium. Since Zr is a hexagonally close packed (hcp) material, it is impossible to describe its plastic response under arbitrary loading conditions with any associated flow rule (e.g. von Mises). As a result of strong tension compression asymmetry of the yield stress and anisotropy, zirconium displays plastic behavior that requires a more sophisticated approach. Consequently, a new general asymmetric yield function has been developed which accommodates mathematically the four directional anisotropies along 0 degrees, 45 degrees, 90 degrees, and biaxial, under tension and compression. Stress anisotropy has been completely decoupled from the r value by using non associated flow plasticity, where yield function and plastic potential have been treated separately to take care of stress and r value directionalities, respectively. This theoretical development has been verified using Zr alloys at room temperature as an example as these materials have very strong SD (Strength Differential) effect. The proposed yield function reasonably well models the evolution of yield surfaces for a zirconium clock rolled plate during in plane and through thickness compression. It has been found that this function can predict both tension and compression asymmetry mathematically without any numerical tolerance and shows the significant improvement compared to any reported functions. Finally, in the end of the report, a program of further research is outlined aimed at constructing tensorial relationships for the temperature and fluence dependent creep surfaces for Zr, Zircaloy 2, and Zircaloy 4.

  7. Magnesium Research in the Automotive Lightweighting Materials...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Life Cycle Modeling of Propulsion Materials Overview of LightweightingMaterials: Past, Present and FutureMaterials Ionic Liquids as Novel Engine Lubricants or Lubricant...

  8. A Probabilistic-Micro-mechanical Methodology for Assessing Zirconium Alloy Cladding Failure

    SciTech Connect (OSTI)

    Pan, Y.M. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX, 78238 (United States); Chan, K.S.; Riha, D.S. [Southwest Research Institute, San Antonio, TX, 78238 (United States)

    2007-07-01T23:59:59.000Z

    Cladding failure of fuel rods caused by hydride-induced embrittlement is a reliability concern for spent nuclear fuel after extended burnup. Uncertainties in the cladding temperature, cladding stress, oxide layer thickness, and the critical stress value for hydride reorientation preclude an assessment of the cladding failure risk. A set of micro-mechanical models for treating oxide cracking, blister cracking, delayed hydride cracking, and cladding fracture was developed and incorporated in a computer model. Results obtained from the preliminary model calculations indicate that at temperatures below a critical temperature of 318.5 deg. C [605.3 deg. F], the time to failure by delayed hydride cracking in Zr-2.5%Nb decreased with increasing cladding temperature. The overall goal of this project is to develop a probabilistic-micro-mechanical methodology for assessing the probability of hydride-induced failure in Zircaloy cladding and thereby establish performance criteria. (authors)

  9. Hydrodynamic effects of eroded materials on response of plasma-facing component during a tokamak disruption

    SciTech Connect (OSTI)

    Hassanein, A.; Konkashbaev, I.

    1999-10-25T23:59:59.000Z

    Loss of plasma confinement causes surface and structural damage to plasma-facing materials (PFMs) and remains a major obstacle for tokamak reactors. The deposited plasma energy results in surface erosion and structural failure. The surface erosion consists of vaporization, spallation, and liquid splatter of metallic materials, while the structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. Comprehensive models (contained in the HEIGHTS computer simulation package) are being used self-consistently to evaluate material damage. Splashing mechanisms occur as a result of volume bubble boiling and liquid hydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials. The effect of macroscopic erosion on total mass losses and lifetime is evaluated. The macroscopic erosion products may further protect PFMs from severe erosion (via the droplet-shielding effect) in a manner similar to that of the vapor shielding concept.

  10. EMSL - battery materials

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    battery-materials en Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations. http:www.emsl.pnl.govemslwebpublicationsmodeling-interfacial-glass-wa...

  11. Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs

    SciTech Connect (OSTI)

    Khaleel, Mohammad A.; Simonen, Fredric A.

    2009-05-01T23:59:59.000Z

    The work described in this report applies probabilistic structural mechanics models to predict the reliability of nuclear pressure boundary components. These same models are then applied to evaluate the effectiveness of alternative programs for inservice inspection to reduce these failure probabilities. Results of the calculations support the development and implementation of risk-informed inservice inspection of piping and vessels. Studies have specifically addressed the potential benefits of ultrasonic inspections to reduce failure probabilities associated with fatigue crack growth and stress-corrosion cracking. Parametric calculations were performed with the computer code pc-PRAISE to generate an extensive set of plots to cover a wide range of pipe wall thicknesses, cyclic operating stresses, and inspection strategies. The studies have also addressed critical inputs to fracture mechanics calculations such as the parameters that characterize the number and sizes of fabrication flaws in piping welds. Other calculations quantify uncertainties associated with the inputs calculations, the uncertainties in the fracture mechanics models, and the uncertainties in the resulting calculated failure probabilities. A final set of calculations address the effects of flaw sizing errors on the effectiveness of inservice inspection programs.

  12. MATERIALS CURRICULUM Major: Core Courses : 21 Credits

    E-Print Network [OSTI]

    Srinivasan, N.

    :0 Diffusion in Solids MT 225 3:0 Deformation and Failure Mechanisms at Elevated Temperatures MT 233 3, and nanotechnology. MT 101 3:0 January (4th Semester) Introduction to Materials Science Bonding, types of materials of structural characterization. Thermodynamics of solid solutions, phase diagrams, defects, diffusion

  13. Formulations, simulations and evaluations associated with thermo-mechanical models for underground coal gasification

    SciTech Connect (OSTI)

    Advani, S.H.

    1983-01-01T23:59:59.000Z

    Model formulations and governing equations for the investigation of the thermo-mechanical, consolidation and failure responses associated with UCG are given. Typical results from sample finite element model representations are presented. The examples quoted include the simulation of the transient temperature profiles, thermo-elastic stresses incorporating temperature dependent material properties and fracture responses. The application of the developed models to the evaluation of field experiments is demonstrated by the simulation of the Hoe Creek II experiments. The numerical experiments for different overburden failure thresholds demonstrated the pronounced sensitivity of the predicted cavity shapes with respect to the assumed properties.

  14. UQ and V&V techniques applied to experiments and simulations of heated pipes pressurized to failure.

    SciTech Connect (OSTI)

    Romero, Vicente Jose; Dempsey, J. Franklin; Antoun, Bonnie R.

    2014-05-01T23:59:59.000Z

    This report demonstrates versatile and practical model validation and uncertainty quantification techniques applied to the accuracy assessment of a computational model of heated steel pipes pressurized to failure. The Real Space validation methodology segregates aleatory and epistemic uncertainties to form straightforward model validation metrics especially suited for assessing models to be used in the analysis of performance and safety margins. The methodology handles difficulties associated with representing and propagating interval and/or probabilistic uncertainties from multiple correlated and uncorrelated sources in the experiments and simulations including: material variability characterized by non-parametric random functions (discrete temperature dependent stress-strain curves); very limited (sparse) experimental data at the coupon testing level for material characterization and at the pipe-test validation level; boundary condition reconstruction uncertainties from spatially sparse sensor data; normalization of pipe experimental responses for measured input-condition differences among tests and for random and systematic uncertainties in measurement/processing/inference of experimental inputs and outputs; numerical solution uncertainty from model discretization and solver effects.

  15. Fatigue failure in thin-film polysilicon is due to subcriticalcracking within the oxide layer

    SciTech Connect (OSTI)

    Alsem, D.H.; Muhlstein, C.L.; Stach, E.A.; Ritchie, R.O.

    2005-01-11T23:59:59.000Z

    It has been established that microelectromechanical systems (MEMS) created from polycrystalline silicon thin-films are subject to cyclic fatigue. Prior work by the authors has suggested that although bulk silicon is not susceptible to fatigue failure in ambient air, fatigue in micron-scale silicon is a result of a ''reaction-layer'' process, whereby high stresses induce a thickening of the post-release oxide at stress concentrations such as notches, which subsequently undergoes moisture-assisted cracking. However, there exists some controversy regarding the post-release oxide thickness of the samples used in the prior study. In this Letter, we present data from devices from a more recent fabrication run that confirm our prior observations. Additionally, new data from tests in high vacuum show that these devices do not fatigue when oxidation and moisture are suppressed. Each of these observations lends credence to the '''reaction-layer'' mechanism. Recent advances in the design of microelectromechanical systems (MEMS) have increased the demand for more reliable microscale structures. Although silicon is an effective and widely used structural material at the microscale, it is very brittle. Consequently, reliability is a limiting factor for commercial and defense applications. Since the surface to volume ratio of these structural films is very large, classical models for failure modes in bulk materials cannot always be applied. For example, whereas bulk silicon is immune to cyclic fatigue failure thin micron-scale structural films of silicon appear to be highly susceptible. It is clear that at these size scales, surface effects may become dominant in controlling mechanical properties. The main reliability issues for MEMS are stiction, fatigue and wear. Fatigue is important in cases where devices are subjected to a large number of loading cycles with amplitudes below their (single-cycle) fracture stress, which may arise due to vibrations intentionally induced in the structure (i.e. a resonator) or those which arise from the service environment. While the reliability of MEMS has received extensive attention, the physical mechanisms responsible for these failure modes have yet to be conclusively determined. This is particularly true for fatigue, where the mechanisms have been subject to intense debate. Recently we have proposed that the fatigue of micron-scale polysilicon is associated with stress-induced surface oxide thickening and moisture-assisted subcritical cracking in the amorphous SiO{sub 2} oxide layer (''reaction-layer'' fatigue). The mechanism of oxide thickening is as yet unknown, but is likely related to some form of stress-assisted diffusion. Allameh et al. suggest a complementary mechanism involving stress-assisted oxide thickening, caused by dissolution of the surface oxide which forms deep grooves that are sites for crack initiation. Kahn et al. have criticized these mechanisms and proposed that, instead, fatigue is caused by subcritical cracking due to contacting surface asperities in the compressive part of the cycle. To the authors' knowledge, there is no direct experimental observation of such asperity contact. Also, their model cannot explain why micron-scale silicon, and not bulk silicon, is susceptible to fatigue. Moreover, Kahn et al. do not acknowledge the role of stress-induced oxide thickening, which has been observed directly using TEM and indirectly using atomic-force microscope measurements by several investigators, and have questioned whether the materials utilized by Muhlstein et al. and Allameh et al. were representative due to the relatively thick oxide scales. Accordingly, the goal of the present research is to seek a definitive understanding of the physical mechanisms responsible for fatigue in polysilicon structural thin-films. Our approach is to combine on-chip testing methods with electron microscopy by fatiguing thin-film samples and observing them, in an unthinned condition, using high-voltage transmission electron microscopy (HVTEM). Two principal results are found from this work: (1

  16. Local Failure in Resected N1 Lung Cancer: Implications for Adjuvant Therapy

    SciTech Connect (OSTI)

    Higgins, Kristin A., E-mail: kristin.higgins@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Chino, Junzo P. [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Berry, Mark [Department of Surgery, Division of Cardiovascular and Thoracic Surgery, Duke University Medical Center, Durham, NC (United States); Ready, Neal [Department of Medicine, Division of Medical Oncology, Duke University Medical Center, Durham, NC (United States); Boyd, Jessamy [US Oncology, Dallas, TX (United States); Yoo, David S.; Kelsey, Chris R. [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)

    2012-06-01T23:59:59.000Z

    Purpose: To evaluate actuarial rates of local failure in patients with pathologic N1 non-small-cell lung cancer and to identify clinical and pathologic factors associated with an increased risk of local failure after resection. Methods and Materials: All patients who underwent surgery for non-small-cell lung cancer with pathologically confirmed N1 disease at Duke University Medical Center from 1995-2008 were identified. Patients receiving any preoperative therapy or postoperative radiotherapy or with positive surgical margins were excluded. Local failure was defined as disease recurrence within the ipsilateral hilum, mediastinum, or bronchial stump/staple line. Actuarial rates of local failure were calculated with the Kaplan-Meier method. A Cox multivariate analysis was used to identify factors independently associated with a higher risk of local recurrence. Results: Among 1,559 patients who underwent surgery during the time interval, 198 met the inclusion criteria. Of these patients, 50 (25%) received adjuvant chemotherapy. Actuarial (5-year) rates of local failure, distant failure, and overall survival were 40%, 55%, and 33%, respectively. On multivariate analysis, factors associated with an increased risk of local failure included a video-assisted thoracoscopic surgery approach (hazard ratio [HR], 2.5; p = 0.01), visceral pleural invasion (HR, 2.1; p = 0.04), and increasing number of positive N1 lymph nodes (HR, 1.3 per involved lymph node; p = 0.02). Chemotherapy was associated with a trend toward decreased risk of local failure that was not statistically significant (HR, 0.61; p = 0.2). Conclusions: Actuarial rates of local failure in pN1 disease are high. Further investigation of conformal postoperative radiotherapy may be warranted.

  17. Nickel alloy stud bolts failure: A case history

    SciTech Connect (OSTI)

    Toffolo, G.; Fassina, P.; Marangoni, M. [AGIP SpA, Milan (Italy); Msallem, A. [AGIP Oil, Tripoli (Libyan Arab Jamahiriya)

    1996-12-01T23:59:59.000Z

    High strength and corrosion resistance material as Inconel X-750 has been selected for the seal flange bolts in an off-shore field in Libya, due to its properties at high temperature, needed for compliance with Fire Safe requirements. After 4 years from the production start-up, during a routine maintenance of wellheads, some bolts have been found cracked. The paper deals with all the activities done in order to understand the cause of the failure. In particular failure analysis has been carried out through laboratory investigation, and shop tests have been conducted to confirm the field procedure and determine the tension on the bolts during the installation. The main conclusion was that the bolts failed due to the concurrence of stress (over-torque that means stress level higher than yield one) and corrosion (pit/crevice conditions). This environmentally assisted failure is known as Hydrogen Embrittlement (HE). Test carried out using the same X-mas tree mounted on the platform justifies the assumption that in the field, where the conditions are far from the ideal, it is possible that even when a uniform torque is set, the tensile stress applied to the bolts is not uniform, making the situation critical. From the corrosion side, the failed bolts showed some corrosion points near the cracks, as due to environment in the crevice/pitting conditions required to justify the hydrogen presence (the bolts are not cathodically protected). Fatigue has been demonstrated not to be responsible for the failure. Solutions are recommended which can safely be adopted during the installation and the substitution of bolts on an existing wellhead, which is operative under pressure without shutting in the well, and not impairing the safety operating envelope.

  18. Improving service availability during link failure transients through alternate routing

    E-Print Network [OSTI]

    Vellanki, Siridhar

    2003-01-01T23:59:59.000Z

    A link failure in a network results in interruption of service for many end users. Currently, routers observing a link failure, recompute their routing tables to find new routes around the failure. However, the network drops packets in the transient...

  19. Sandia National Laboratories: Failure Mode and Effect Analysis...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ProcessFailure Mode and Effect Analysis (FMEA) Tutorial Failure Mode and Effect Analysis (FMEA) Tutorial Failure Mode and Effect Analysis (FMEA) Tutorial (SAND2012-0602W) Tagged...

  20. Analytical modeling in support of the development of fiber reinforced ceramic composite materials for re-heater burners

    SciTech Connect (OSTI)

    Kibler, J.J. [Materials Sciences Corp., Fort Washington, PA (United States); DiPietro, S.G. [Textron Specialty Materials, Lowell, MA (United States)

    1995-10-01T23:59:59.000Z

    Development of Continuous Fiber reinforced Ceramic Composite (CFCC) materials is a process of identifying components which will benefit from CFCC properties, and defining appropriate composite constructions which will provide materials which will meet the structural and thermal requirements of the application. Materials Sciences Corporation (MSC) has been providing analytical support to Textron Specialty Materials in the development of re-heated tubes for metal reheating furnaces. As part of this support, a study has been made of the sensitivity of composite properties to fiber orientation as well as a number of matrix properties which control the stress-strain behavior of the composite.

  1. Impact of Motor Failures on Payback Periods

    E-Print Network [OSTI]

    Cheek, K. F.; Pillay, P.; Dudley, K. J.

    This paper uses MotorMaster and Vaughen's Complete Price Guide to determine payback periods for different motor failure scenarios. Some scenarios considered are rewinds, reconditions, and replacement of bearings. Prices for these repairs...

  2. Autonomous Thruster Failure Recovery for Underactuated Spacecraft

    E-Print Network [OSTI]

    . Miller September 2010 SSL #13­10 #12;2 #12;Autonomous Thruster Failure Recovery for Underactuated Spacecraft Christopher Masaru Pong, David W. Miller September 2010 SSL #12­11 This work is based

  3. NREL Test-to-Failure Protocol (Presentation)

    SciTech Connect (OSTI)

    Hacke, P.

    2012-03-01T23:59:59.000Z

    The presentation describes the test-to-failure protocol that was developed and piloted at NREL, stressing PV modules with multiple applications of damp heat (with bias) and thermal cycling until they fail.

  4. Individual Reactions to Failure in Virtual Teams

    E-Print Network [OSTI]

    Diaz, Ismael

    2012-02-14T23:59:59.000Z

    were more situational than attributions in the distributed condition, which were more dispositional. This finding supports the notion that collaboration configuration is important for understanding reactions to teammate failure....

  5. Universitat Augsburg Failure-Sensitive Specification

    E-Print Network [OSTI]

    Reif, Wolfgang

    techniques like fault tree analysis (FTA) [14], failure modes and effects analysis (FMEA), or preliminary as well. In this context we already formalized techniques like FTA [12][4] or FMEA. This paper presents

  6. Integrating Electricity Subsector Failure Scenarios into a Risk...

    Energy Savers [EERE]

    Integrating Electricity Subsector Failure Scenarios into a Risk Assessment Methodology (December 2013) Integrating Electricity Subsector Failure Scenarios into a Risk Assessment...

  7. DOE Collects Civil Penalties for Failure to Certify Consumer...

    Office of Environmental Management (EM)

    Collects Civil Penalties for Failure to Certify Consumer Refrigeration Products DOE Collects Civil Penalties for Failure to Certify Consumer Refrigeration Products April 22, 2015 -...

  8. abc heart failure: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    symptoms of acute heart failure and consecutive multiorgan failure for further treatment and to evaluate the indication for implantation of a ventricular assist device or...

  9. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 14 (2006) 283297 doi:10.1088/0965-0393/14/2/011

    E-Print Network [OSTI]

    Deymier, Pierre

    2006-01-01T23:59:59.000Z

    such as pinwheels and microturbines is rendered very short as they are frequently subjected to wear related failure

  10. Failure mechanisms of polyimide and perfluoroalkoxy films under high frequency pulses

    E-Print Network [OSTI]

    Southampton, University of

    Failure mechanisms of polyimide and perfluoroalkoxy films under high frequency pulses Weijun Yin1 of polyimide and perfluoroalkoxy high temperature films under unipolar and bipolar repetitive pulses of art high temperature insulation materials, such as polyimide (PI), and perfluoroalkoxy (PFA) films

  11. Sandia National Laboratories: Materials Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Biomass, Computational Modeling & Simulation, CRF, Energy, Energy Storage, Materials Science, News, News & Events, Nuclear Energy, Partnership, Renewable Energy, Research &...

  12. Effective flow surface of porous materials with two populations of voids under internal pressure: I. a GTN model

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ). Such a microstructure is typical of the highly irradiated uranium dioxide (UO2), a nuclear fuel commonly used in nuclear several studies on the mechanical behavior of highly irradiated nuclear fuels at different scales (Vincent to the effective plastic flow surface of a bi-porous material saturated by a fluid. The material under

  13. Failure Analysis of Ceramic Components

    SciTech Connect (OSTI)

    B.W. Morris

    2000-06-29T23:59:59.000Z

    Ceramics are being considered for a wide range of structural applications due to their low density and their ability to retain strength at high temperatures. The inherent brittleness of monolithic ceramics requires a departure from the deterministic design philosophy utilized to analyze metallic structural components. The design program ''Ceramic Analysis and Reliability Evaluation of Structures Life'' (CARES/LIFE) developed by NASA Lewis Research Center uses a probabilistic approach to predict the reliability of monolithic components under operational loading. The objective of this study was to develop an understanding of the theories used by CARES/LIFE to predict the reliability of ceramic components and to assess the ability of CARES/LIFE to accurately predict the fast fracture behavior of monolithic ceramic components. A finite element analysis was performed to determine the temperature and stress distribution of a silicon carbide O-ring under diametral compression. The results of the finite element analysis were supplied as input into CARES/LIFE to determine the fast fracture reliability of the O-ring. Statistical material strength parameters were calculated from four-point flexure bar test data. The predicted reliability showed excellent correlation with O-ring compression test data indicating that the CARES/LIFE program can be used to predict the reliability of ceramic components subjected to complicated stress states using material properties determined from simple uniaxial tensile tests.

  14. Investigation of thermal processes in one-and two-layer materials under irradiation with high-energy heavy ions within the thermal peak model

    SciTech Connect (OSTI)

    Amirkhanov, I. V., E-mail: ibrohim@jinr.ru; Didyk, A. Yu.; Muzafarov, D. Z.; Puzynin, I. V.; Puzynina, T. P.; Sarker, N. R.; Sarhadov, I.; Sharipov, Z. A. [Joint Institute for Nuclear Research, Laboratory of Information Technologies (Russian Federation)

    2006-12-15T23:59:59.000Z

    A system of equations for the electron and lattice temperatures around and along the path of a 700-MeV heavy (uranium) ion in nickel (one-layer material) is solved numerically in the axially symmetric cylindrical coordinate system under the assumption of temperature-dependent specific heat and thermal conductivity. The obtained dependences of the lattice temperature on the radius (distance from the ion path) and depth suggest that the ionization energy loss of a 700-MeV uranium ion in nickel is sufficient to melt the material. A comparative analysis with the linear model is performed and the maximum radius and depth of the region where the target material can melt is estimated. Then, the initial system of equations is solved for the region around and along the path of a 710-MeV heavy (bismuth {sup 209}Bi) ion in the two-layer material Ni(2 {mu}m)-W with constant thermophysical parameters. The obtained dependences of the lattice temperature on the radius and depth show that the ionization energy loss of a 710-MeV bismuth ion in this two-layer material is sufficient for melting. The maximum radius and depth of the regions in the target material where phase transitions may occur are estimated.

  15. Characterization of materials for a reactive transport model validation experiment: Interim report on the caisson experiment. Yucca Mountain Site Characterization Project

    SciTech Connect (OSTI)

    Siegel, M.D.; Cheng, W.C. [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences

    1995-08-01T23:59:59.000Z

    Models used in performance assessment and site characterization activities related to nuclear waste disposal rely on simplified representations of solute/rock interactions, hydrologic flow field and the material properties of the rock layers surrounding the repository. A crucial element in the design of these models is the validity of these simplifying assumptions. An intermediate-scale experiment is being carried out at the Experimental Engineered Test Facility at Los Alamos Laboratory by the Los Alamos and Sandia National Laboratories to develop a strategy to validate key geochemical and hydrological assumptions in performance assessment models used by the Yucca Mountain Site Characterization Project.

  16. Defect induced plasticity and failure mechanism of boron nitride nanotubes under tension

    SciTech Connect (OSTI)

    Anoop Krishnan, N. M., E-mail: anoopnm@civil.iisc.ernet.in; Ghosh, Debraj [Indian Institute of Science, Bangalore 560012 (India)

    2014-07-28T23:59:59.000Z

    The effects of Stone-Wales (SW) and vacancy defects on the failure behavior of boron nitride nanotubes (BNNTs) under tension are investigated using molecular dynamics simulations. The Tersoff-Brenner potential is used to model the atomic interaction and the temperature is maintained close to 300?K. The effect of a SW defect is studied by determining the failure strength and failure mechanism of nanotubes with different radii. In the case of a vacancy defect, the effect of an N-vacancy and a B-vacancy is studied separately. Nanotubes with different chiralities but similar diameter is considered first to evaluate the chirality dependence. The variation of failure strength with the radius is then studied by considering nanotubes of different diameters but same chirality. It is observed that the armchair BNNTs are extremely sensitive to defects, whereas the zigzag configurations are the least sensitive. In the case of pristine BNNTs, both armchair and zigzag nanotubes undergo brittle failure, whereas in the case of defective BNNTs, only the zigzag ones undergo brittle failure. An interesting defect induced plastic behavior is observed in defective armchair BNNTs. For this nanotube, the presence of a defect triggers mechanical relaxation by bond breaking along the closest zigzag helical path, with the defect as the nucleus. This mechanism results in a plastic failure.

  17. Parallel algorithms with processor failures and delays. Technical report

    SciTech Connect (OSTI)

    Buss, J.F.; Kanellakis, P.C.; Radge, P.L.; Shvartsman, A.A.

    1991-08-01T23:59:59.000Z

    The authors study efficient deterministic parallel algorithms on two models: restartable fail-stop CRCW PRAMs and strongly asynchronous PRAMs. In the first model, synchronous processors are subject to arbitrary stop failures and restarts determined by an on-line adversary and involving loss of private but not shared memory; the complexity measures are completed work (where processors are charged for completed fixed-size update cycles) and overhead ratio (completed work amortized over necessary work and failure). In the second model, the result of the computation is a serialization of the actions of the processors determined by an on-line adversary; the complexity measure is total work (number of steps taken by all processors). Despite their differences the two models share key algorithmic techniques. They present new algorithms for the Write-All problem (in which P processors write ones into an array of size N) for these two models. These algorithms can be used to implement a simulation strategy for any N processor PRAM on a restartable fail-stop P processor CRCW PRAM such that it guarantees a terminating execution of each simulated N processor step, with O(log sq N) overhead ratio.

  18. Methodology for developing Version 2.0 of the MECcheck{trademark} materials for the 1992, 1993, and 1995 Model Energy Codes

    SciTech Connect (OSTI)

    Connell, L.M.; Lucas, R.G.; Taylor, Z.T.

    1996-06-01T23:59:59.000Z

    To help builders comply with the Council of American Building Officials (CABO) Model Energy Code (MEC), and to help code officials enforce the MEC requirements, the US Department of Energy (DOE) directed Pacific Northwest National Laboratory (PNNL) to develop the MECcheck{trademark} compliance materials. The materials include a compliance and enforcement manual for all the MEC requirements, prescriptive packages, software, and a trade-off worksheet (included in the compliance manual) to help comply with the thermal envelope requirements. The materials can be used for single-family and low- rise multifamily dwellings. The materials allow building energy efficiency measures (such as insulation levels) to be ``traded off`` against each other, allowing a wide variety of building designs to comply with the MEC. The materials were developed to provide compliance methods that are easy to use and understand. MECcheck compliance materials have been developed for three different editions of the MEC: the 1992, 1993, and 1995 editions. Although some requirements contained in the 1992, 1993, and 1995 MEC changed, the methodology used to develop the MECcheck materials for these three editions is essentially identical. This document explains the methodology used to produce the three MECcheck compliance approaches for meeting the MEC`s thermal envelope requirements--the prescriptive package approach, the software approach, and the trade-off approach. The MECcheck material are largely oriented to assisting the builder in meeting the most complicated part of the MEC--the building envelope U{sub o}-, U-, and R-value requirements in Section 502 of the MEC. This document details the calculations and assumptions underlying the treatment of the MEC requirements in MECcheck, with a major emphasis on the building envelope requirements.

  19. A streamlined failure mode and effects analysis

    SciTech Connect (OSTI)

    Ford, Eric C., E-mail: eford@uw.edu; Smith, Koren; Terezakis, Stephanie; Croog, Victoria; Gollamudi, Smitha; Gage, Irene; Keck, Jordie; DeWeese, Theodore; Sibley, Greg [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287 (United States)] [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287 (United States)

    2014-06-15T23:59:59.000Z

    Purpose: Explore the feasibility and impact of a streamlined failure mode and effects analysis (FMEA) using a structured process that is designed to minimize staff effort. Methods: FMEA for the external beam process was conducted at an affiliate radiation oncology center that treats approximately 60 patients per day. A structured FMEA process was developed which included clearly defined roles and goals for each phase. A core group of seven people was identified and a facilitator was chosen to lead the effort. Failure modes were identified and scored according to the FMEA formalism. A risk priority number,RPN, was calculated and used to rank failure modes. Failure modes with RPN > 150 received safety improvement interventions. Staff effort was carefully tracked throughout the project. Results: Fifty-two failure modes were identified, 22 collected during meetings, and 30 from take-home worksheets. The four top-ranked failure modes were: delay in film check, missing pacemaker protocol/consent, critical structures not contoured, and pregnant patient simulated without the team's knowledge of the pregnancy. These four failure modes hadRPN > 150 and received safety interventions. The FMEA was completed in one month in four 1-h meetings. A total of 55 staff hours were required and, additionally, 20 h by the facilitator. Conclusions: Streamlined FMEA provides a means of accomplishing a relatively large-scale analysis with modest effort. One potential value of FMEA is that it potentially provides a means of measuring the impact of quality improvement efforts through a reduction in risk scores. Future study of this possibility is needed.

  20. DETERMINATION OF ELECTROCHEMICAL PERFORMANCE, AND THERMO-MECHANICALCHEMICAL STABILITY OF SOFCS FROM DEFECT MODELING

    SciTech Connect (OSTI)

    Wachsman, E.D.; Duncan, K.L.; Ebrahimi, F.

    2005-01-27T23:59:59.000Z

    The objectives of this project were to: provide fundamental relationships between SOFC performance and operating conditions and transient (time dependent) transport properties; extend models to thermo-mechanical stability, thermo-chemical stability, and multilayer structures; incorporate microstructural effects such as grain boundaries and grain-size distribution; experimentally verify models and devise strategies to obtain relevant material constants; and assemble software package for integration into SECA failure analysis models.

  1. A Study to Verify the Material Surface Concept of Water Table by Examining Analytical and Numerical Models.

    E-Print Network [OSTI]

    Dadi, Sireesh Kumar

    2011-10-21T23:59:59.000Z

    The highly nonlinear nature of unsaturated flow results in different ways to approximate the delayed or instantaneous movement of the water table. In nearly all the approaches, the water table is conceptually treated as a “material surface...

  2. Vehicle Technologies Office Merit Review 2015: Validation of Material Models for Crash Simulation of Automotive Carbon Fiber Composite Structures (VMM)

    Broader source: Energy.gov [DOE]

    Presentation given by Ford Motor Company at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about validation of material...

  3. Covetic Materials

    Energy Savers [EERE]

    Can re-melt, dilute, alloy... Fabrication of Covetic Materials - Nanocarbon Infusion 3 4 Technical Approach Unusual Characteristics of Covetic Materials ("covalent" &...

  4. Ductile failure X-prize.

    SciTech Connect (OSTI)

    Cox, James V.; Wellman, Gerald William; Emery, John M.; Ostien, Jakob T.; Foster, John T.; Cordova, Theresa Elena; Crenshaw, Thomas B.; Mota, Alejandro; Bishop, Joseph E.; Silling, Stewart Andrew; Littlewood, David John; Foulk, James W., III; Dowding, Kevin J.; Dion, Kristin; Boyce, Brad Lee; Robbins, Joshua H.; Spencer, Benjamin Whiting

    2011-09-01T23:59:59.000Z

    Fracture or tearing of ductile metals is a pervasive engineering concern, yet accurate prediction of the critical conditions of fracture remains elusive. Sandia National Laboratories has been developing and implementing several new modeling methodologies to address problems in fracture, including both new physical models and new numerical schemes. The present study provides a double-blind quantitative assessment of several computational capabilities including tearing parameters embedded in a conventional finite element code, localization elements, extended finite elements (XFEM), and peridynamics. For this assessment, each of four teams reported blind predictions for three challenge problems spanning crack initiation and crack propagation. After predictions had been reported, the predictions were compared to experimentally observed behavior. The metal alloys for these three problems were aluminum alloy 2024-T3 and precipitation hardened stainless steel PH13-8Mo H950. The predictive accuracies of the various methods are demonstrated, and the potential sources of error are discussed.

  5. UTILITIES PROBLEMS AND FAILURES Electrical or plumbing failure/Flooding/Water leak/Natural gas

    E-Print Network [OSTI]

    Fernandez, Eduardo

    UTILITIES PROBLEMS AND FAILURES Electrical or plumbing failure/Flooding/Water leak/Natural gas for electrical shock. NOTIFY University Police. What should I do if I smell natural or propane gas? LEAVE/Repair line, 7-6333, or CALL the Campus University Police or Security at (561) 297-3500 or 911

  6. UTILITIES PROBLEMS AND FAILURES ELECTRICAL OR PLUMBING FAILURE/FLOODING/WATER LEAK

    E-Print Network [OSTI]

    Fernandez, Eduardo

    UTILITIES PROBLEMS AND FAILURES ELECTRICAL OR PLUMBING FAILURE/FLOODING/WATER LEAK NATURAL GAS - F 8a - 5p HBOI@FAU Security (772) 216-1124 Afterhours, Weekends or Holidays What should I do Police 911. · NOTIFY Building Safety personnel when possible. What should I do if I smell natural

  7. UTILITIES PROBLEMS AND FAILURES Electrical or plumbing failure/Flooding/Water leak/Natural gas or

    E-Print Network [OSTI]

    Fernandez, Eduardo

    UTILITIES PROBLEMS AND FAILURES Electrical or plumbing failure/Flooding/Water leak/Natural gas Physical Plant (772) 242-2246 M - F 8a - 5p (954) 762-5040 HBOI@FAU Security (772) 216-1124 Afterhours University Police. NOTIFY Building Safety personnel when possible. What should I do if I smell natural

  8. Materials Scientist

    Broader source: Energy.gov [DOE]

    Alternate Title(s):Materials Research Engineer; Metallurgical/Chemical Engineer; Product Development Manager;

  9. Polymer Filler Aging and Failure Studied by Lateral Force Microscopy

    SciTech Connect (OSTI)

    Ratto, T; Saab, A P

    2009-05-27T23:59:59.000Z

    In the present work, we study, via force microscopy, the basic physical interactions of a single bead of silica filler with a PDMS matrix both before and after exposure to gamma radiation. Our goal was to confirm our results from last year, and to explore force microscopy as a means of obtaining particle-scale polymer/filler interactions suitable for use as empirical inputs to a computational model consisting of an ensemble of silica beads embedded in a PDMS matrix. Through careful calibration of a conventional atomic force microscope, we obtained both normal and lateral force data that was fitted to yield adhesion, surface shear modulus, and friction of a 1 {micro}m silica bead in contact with PDMS layers of various thickness. Comparison of these terms before and after gamma exposure indicated that initially, radiation exposure lead to softening of the PDMS, but eventually resulted in stiffening. Simultaneously, adhesion between the polymer and silica decreased. This could indicate a serious failure path for filled PDMS exposed to radiation, whereby stiffening of the bulk polymer leads to loss of compressive elastic behavior, while a decrease in polymer filler adhesion results in an increased likelihood of stress failure under load. In addition to further testing of radiation damaged polymers, we also performed FEA modeling of silica beads in a silicone matrix using the shear modulus and adhesion values isolated from the force microscopy experiments as model inputs. The resulting simulation indicated that as a polymer stiffens due to impinging radiation, it also undergoes weakening of adhesion to the filler. The implication is that radiation induces a compound failure mode in filled polymer systems.

  10. Damage mechanics characterization on fatigue behavior of a solder joint material

    SciTech Connect (OSTI)

    Chow, C.L.; Yang, F. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering; Fang, H.E. [Sandia National Labs., Albuquerque, NM (United States). Computational Physics Dept.

    1998-08-01T23:59:59.000Z

    This paper presents the first part of a comprehensive mechanics approach capable of predicting the integrity and reliability of solder joint material under fatigue loading without viscoplastic damage considerations. A separate report will be made to present a comprehensive damage model describing life prediction of the solder material under thermomechanical fatigue loading. The method is based on a theory of damage mechanics which makes possible a macroscopic description of the successive material deterioration caused by the presence of microcracks/voids in engineering materials. A damage mechanics model based on the thermodynamic theory of irreversible processes with internal state variables is proposed and used to provide a unified approach in characterizing the cyclic behavior of a typical solder material. With the introduction of a damage effect tensor, the constitutive equations are derived to enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The fatigue evolution is subsequently developed based on the hypothesis that the overall damage is induced by the accumulation of fatigue and plastic damage. This damage mechanics approach offers a systematic and versatile means that is effective in modeling the entire process of material failure ranging from damage initiation and propagation leading eventually to macro-crack initiation and growth. As the model takes into account the load history effect and the interaction between plasticity damage and fatigue damage, with the aid of a modified general purpose finite element program, the method can readily be applied to estimate the fatigue life of solder joints under different loading conditions.

  11. Finite Element Studies in the Out-Of-Plane Failure of Unreinfored Masonry

    E-Print Network [OSTI]

    Martini, Kirk

    , modelling phenomena resulting from different elastic properties of block and mortar. · Joints and associated local effects at the block-mortar interface, instead model- ling the mortar joints as potential lines of failure due to cracking. · Joints are smeared out. In this approach, the block-mortar composite

  12. On the Role of Power-Grid and Communication-System Interdependencies on Cascading Failures

    E-Print Network [OSTI]

    Hayat, Majeed M.

    the fact that today's power grids are reliable and the control and communication systems have been deployed involved in the modeling of interactions between interdependent systems, modeling the coupled powerOn the Role of Power-Grid and Communication- System Interdependencies on Cascading Failures Mahshid

  13. Effects of pacing site on global and regional left ventricular function in the setting of dyssynchronous heart failure

    E-Print Network [OSTI]

    Howard, Elliot Jacob

    2011-01-01T23:59:59.000Z

    modeling of dyssynchronous heart failure: A case study.in the dyssynchronous canine heart. Annual Meeting of therelaxation. Am J Physiol Heart Circ Physiol 286: H640-647,

  14. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) Application in the Evaluation of Management Risks

    E-Print Network [OSTI]

    Soguilon, Nenita M.

    2009-12-18T23:59:59.000Z

    .3.1. Mechanisms of Prevention ............................................................................................... 11 2.4. Human Factors Process Failure Mode and Effects Analysis (HF PFMEA) ....................... 11 2.5. FMEA Components... ........................................................................................... 15 2.5.5. Risk Priority Number ....................................................................................................... 17 2.6. FMEA Model...

  15. Absolute nuclear material assay

    DOE Patents [OSTI]

    Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

    2012-05-15T23:59:59.000Z

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  16. Absolute nuclear material assay

    DOE Patents [OSTI]

    Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

    2010-07-13T23:59:59.000Z

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  17. Effect of component failures on economics of distributed photovoltaic systems

    SciTech Connect (OSTI)

    Lubin, B

    2012-02-02T23:59:59.000Z

    This report describes an applied research program to assess the realistic costs of grid connected photovoltaic (PV) installations. A Board of Advisors was assembled that included management from the regional electric power utilities, as well as other participants from companies that work in the electric power industry. Although the program started with the intention of addressing effective load carrying capacity (ELCC) for utility-owned photovoltaic installations, results from the literature study and recommendations from the Board of Advisors led investigators to the conclusion that obtaining effective data for this analysis would be difficult, if not impossible. The effort was then re-focused on assessing the realistic costs and economic valuations of grid-connected PV installations. The 17 kW PV installation on the University of Hartford's Lincoln Theater was used as one source of actual data. The change in objective required a more technically oriented group. The re-organized working group (changes made due to the need for more technically oriented participants) made site visits to medium-sized PV installations in Connecticut with the objective of developing sources of operating histories. An extensive literature review helped to focus efforts in several technical and economic subjects. The objective of determining the consequences of component failures on both generation and economic returns required three analyses. The first was a Monte-Carlo-based simulation model for failure occurrences and the resulting downtime. Published failure data, though limited, was used to verify the results. A second model was developed to predict the reduction in or loss of electrical generation related to the downtime due to these failures. Finally, a comprehensive economic analysis, including these failures, was developed to determine realistic net present values of installed PV arrays. Two types of societal benefits were explored, with quantitative valuations developed for both. Some societal benefits associated with financial benefits to the utility of having a distributed generation capacity that is not fossil-fuel based have been included into the economic models. Also included and quantified in the models are several benefits to society more generally: job creation and some estimates of benefits from avoiding greenhouse emissions. PV system failures result in a lowering of the economic values of a grid-connected system, but this turned out to be a surprisingly small effect on the overall economics. The most significant benefit noted resulted from including the societal benefits accrued to the utility. This provided a marked increase in the valuations of the array and made the overall value proposition a financially attractive one, in that net present values exceeded installation costs. These results indicate that the Department of Energy and state regulatory bodies should consider focusing on societal benefits that create economic value for the utility, confirm these quantitative values, and work to have them accepted by the utilities and reflected in the rate structures for power obtained from grid-connected arrays. Understanding and applying the economic benefits evident in this work can significantly improve the business case for grid-connected PV installations. This work also indicates that the societal benefits to the population are real and defensible, but not nearly as easy to justify in a business case as are the benefits that accrue directly to the utility.

  18. Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

    SciTech Connect (OSTI)

    Brian Curtis Anderson

    2002-08-27T23:59:59.000Z

    The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to understand the subsequent chapters, as well as a literature review of these topics. Chapter two is a paper that has been published in the ''Journal of Controlled Release'' that examines the mechanism of drug release from a polymer gel, as well as experimental design suggestions for the evaluation of water soluble drug delivery systems. Chapter three is a paper that has been published in the ''Journal of Pharmaceutical Sciences'' that discusses the effect ionic salts have on properties of the polymer systems examined in chapter two. Chapter four is a paper published in the Materials Research Society Fall 2000 Symposium Series dealing with the design and synthesis of a pH-sensitive polymeric drug delivery device. Chapter five is a paper that has been published in the journal ''Biomaterials'' proposing a novel polymer/metal composite for use as a biomaterial in hip arthroplasty surgery. Chapter six is a paper that will appear in an upcoming volume of the Journal ''Biomaterials'' dealing with the synthesis of a novel water soluble cationic polymer with possible applications in non-viral gene therapy. Chapter seven is a paper that has been submitted to ''Macromolecules'' discussing several novel block copolymers based on poly(ethylene glycol) and poly(diethylamino ethyl methacrylate) that possess both pH-sensitive and temperature sensitive properties. Chapter eight contains a summary of the research contained in chapters 2-7 and proposes future research for the gene therapy and drug delivery projects.

  19. Celiac Node Failure Patterns After Definitive Chemoradiation for Esophageal Cancer in the Modern Era

    SciTech Connect (OSTI)

    Amini, Arya [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); UC Irvine School of Medicine, Irvine, California (United States); Xiao Lianchun [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Suzuki, Akihiro; Hayashi, Yuki [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Hofstetter, Wayne [Department of Thoracic and Cardiovascular Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Crane, Christopher; Komaki, Ritsuko [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Bhutani, Manoop S.; Lee, Jeffrey H.; Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Welsh, James, E-mail: jwelsh@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-06-01T23:59:59.000Z

    Purpose: The celiac lymph node axis acts as a gateway for metastatic systemic spread. The need for prophylactic celiac nodal coverage in chemoradiation therapy for esophageal cancer is controversial. Given the improved ability to evaluate lymph node status before treatment via positron emission tomography (PET) and endoscopic ultrasound, we hypothesized that prophylactic celiac node irradiation may not be needed for patients with localized esophageal carcinoma. Methods and Materials: We reviewed the radiation treatment volumes for 131 patients who underwent definitive chemoradiation for esophageal cancer. Patients with celiac lymph node involvement at baseline were excluded. Median radiation dose was 50.4 Gy. The location of all celiac node failures was compared with the radiation treatment plan to determine whether the failures occurred within or outside the radiation treatment field. Results: At a median follow-up time of 52.6 months (95% CI 46.1-56.7 months), 6 of 60 patients (10%) without celiac node coverage had celiac nodal failure; in 5 of these patients, the failures represented the first site of recurrence. Of the 71 patients who had celiac coverage, only 5 patients (7%) had celiac region relapse. In multivariate analyses, having a pretreatment-to-post-treatment change in standardized uptake value on PET >52% (odds ratio [OR] 0.198, p = 0.0327) and having failure in the clinical target volume (OR 10.72, p = 0.001) were associated with risk of celiac region relapse. Of those without celiac coverage, the 6 patients that later developed celiac failure had a worse median overall survival time compared with the other 54 patients who did not fail (median overall survival time: 16.5 months vs. 31.5 months, p = 0.041). Acute and late toxicities were similar in both groups. Conclusions: Although celiac lymph node failures occur in approximately 1 of 10 patients, the lack of effective salvage treatments and subsequent low morbidity may justify prophylactic treatment in distal esophageal cancer patients.

  20. Power Grid Vulnerability to Geographically Correlated Failures

    E-Print Network [OSTI]

    Shepard, Kenneth

    Power Grid Vulnerability to Geographically Correlated Failures ­ Analysis and Control Implications such as telecommunications networks [14]. The power grid is vulnerable to natural disasters, such as earthquakes, hurricanes [17], [34]. Thus, we focus on the vulnerability of the power grid to an outage of several lines

  1. Battelle determines cause of Ashland tank failure

    SciTech Connect (OSTI)

    Mesloh, R.E.; Marschall, C.W.; Buchheit, R.D.; Kiefner, J.F. (Battelle Memorial Institute, Columbus, OH (US))

    1988-09-26T23:59:59.000Z

    An existing flaw, combined with embrittled steel and residual stresses, led to the catastrophic failure of the fuel oil tank at Ashland Petroleum Co., Floreffe, Pa., last January. Here is a look at the tank's background, events surrounding its rupture, and Battelle's methods for investigating the incident.

  2. Commutation failures in HVDC transmission systems

    SciTech Connect (OSTI)

    Thio, C.V.; Davies, J.B.; Kent, K.L. [Manitoba Hydro, Winnipeg, Manitoba (Canada)] [Manitoba Hydro, Winnipeg, Manitoba (Canada)

    1996-04-01T23:59:59.000Z

    This paper provides a formulation for the initiation or onset mechanism of commutation failures in line-commutated thyristor converters, assuming infinite (zero impedance) ac systems. A theoretical development and a parametric analysis is given. Theory validation by simulation and comparison to actual field experience data is also given.

  3. Evaluation of Corrosion Failure in Tractor-Trailer Brake System

    SciTech Connect (OSTI)

    Wilson, DF

    2002-10-22T23:59:59.000Z

    As reported to ORNL, concomitant with the introduction of different deicing and anti-icing compounds, there was an increase in the brake failure rate of tractor-trailer trucks. A forensic evaluation of a failed brake system was performed. Optical and scanning electron microscopic evaluation showed corrosion to be mostly confined to the brake table/lining interface. The corrosion is non-uniform as is to be expected for plain carbon steel in chloride environments. This initial analysis found no evidence for the chlorides of calcium and magnesium, which are the newly introduced deicing and antiicing compounds and are less soluble in water than the identified chlorides of sodium and potassium, in the scale. The result could be as a result of non-exposure of the examined brake table to calcium and magnesium chloride. The mechanisms for the increased failure rate are postulated as being an increased rate of corrosion due to positive shifts in the corrosion potential, and an increased amount of corrosion due to an increased ''time of wetness'' that results from the presence of hygroscopic salts. Laboratory scale evaluation of the corrosion of plain carbon steel in simulated deicing and anti-icing solutions need to be performed to determine corrosion rates and morphological development of corrosion product, to compare laboratory data to in-service data, and to rank economically feasible replacement materials for low carbon steel. In addition, the mechanical behavior of the lining attached to the brake shoe table needs to be assessed. It is opined that an appropriate adjustment of materials could easily allow for a doubling of a brake table/lining lifetime. Suggestions for additional work, to clarify the mechanisms of rust jacking and to develop possible solutions, are described.

  4. Survey on Failure Modes and Failure Mechanisms in Digital Components and Systems

    SciTech Connect (OSTI)

    Cetiner, Mustafa Sacit [ORNL; Korsah, Kofi [ORNL; Muhlheim, Michael David [ORNL

    2009-01-01T23:59:59.000Z

    This paper presents the preliminary results of a survey on the operating experience of a broad range of digital components and systems deployed in various industries. The primary objective of this survey is to identify principal modes and mechanisms of failure in field-deployed digital systems. Earlier works have sought to determine the failure rates of various classes of digital devices with the intent to integrate this information into the risk analysis calculations though still immature for such systems. Failure rates of individual components or systems are not taken into account in this evaluation; only failure modes and their respective probabilistic distribution are considered. Preliminary results from two data sources, SPIDR and FARADIP, are presented.

  5. Photomultiplier tube failure under hydrostatic pressure in future neutrino detectors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chambliss, K.; Diwan, M.; Simos, N.; Sundaram, S. K.

    2014-10-01T23:59:59.000Z

    Failure of photomultiplier tubes (PMTs) under hydrostatic pressure is a concern in neutrino detection, specifically, in the proposed Long-Baseline Neutrino Experiment project. Controlled hydrostatic implosion tests were performed on prototypic PMT bulbs of 10-inch diameter and recorded using high speed filming techniques to capture failures in detail. These high-speed videos were analyzed frame-by-frame in order to identify the origin of a crack, measure the progression of individual crack along the surface of the bulb as it propagates through the glass, and estimate crack velocity. Crack velocity was calculated for each individual crack, and an average velocity was determined for allmore »measurable cracks on each bulb. Overall, 32 cracks were measured in 9 different bulbs tested. Finite element modeling (FEM) of crack formation and growth in prototypic PMT shows stress concentration near the middle section of the PMT bulbs that correlates well with our crack velocity measurements in that section. The FEM model predicts a crack velocity value that is close to the terminal crack velocity reported. Our measurements also reveal significantly reduced crack velocities compared to terminal crack velocities measured in glasses using fracture mechanics testing and reported in literature.« less

  6. Photomultiplier tube failure under hydrostatic pressure in future neutrino detectors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chambliss, K. [Alfred Univ., Alfred, NY (United States). Multifunctional Materials Lab, Kazuo Inamori School of Engineering; Diwan, M. [Alfred Univ., Alfred, NY (United States). Multifunctional Materials Lab, Kazuo Inamori School of Engineering; Simos, N. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Sundaram, S. K. [Alfred Univ., Alfred, NY (United States). Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2014-10-01T23:59:59.000Z

    Failure of photomultiplier tubes (PMTs) under hydrostatic pressure is a concern in neutrino detection, specifically, in the proposed Long-Baseline Neutrino Experiment project. Controlled hydrostatic implosion tests were performed on prototypic PMT bulbs of 10-inch diameter and recorded using high speed filming techniques to capture failures in detail. These high-speed videos were analyzed frame-by-frame in order to identify the origin of a crack, measure the progression of individual crack along the surface of the bulb as it propagates through the glass, and estimate crack velocity. Crack velocity was calculated for each individual crack, and an average velocity was determined for all measurable cracks on each bulb. Overall, 32 cracks were measured in 9 different bulbs tested. Finite element modeling (FEM) of crack formation and growth in prototypic PMT shows stress concentration near the middle section of the PMT bulbs that correlates well with our crack velocity measurements in that section. The FEM model predicts a crack velocity value that is close to the terminal crack velocity reported. Our measurements also reveal significantly reduced crack velocities compared to terminal crack velocities measured in glasses using fracture mechanics testing and reported in literature.

  7. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

    SciTech Connect (OSTI)

    Wirth, Brian; Morgan, Dane; Kaoumi, Djamel; Motta, Arthur

    2013-12-01T23:59:59.000Z

    The in-service degradation of reactor core materials is related to underlying changes in the irradiated microstructure. During reactor operation, structural components and cladding experience displacement of atoms by collisions with neutrons at temperatures at which the radiation-induced defects are mobile, leading to microstructure evolution under irradiation that can degrade material properties. At the doses and temperatures relevant to fast reactor operation, the microstructure evolves by dislocation loop formation and growth, microchemistry changes due to radiation-induced segregation, radiation-induced precipitation, destabilization of the existing precipitate structure, and in some cases, void formation and growth. These processes do not occur independently; rather, their evolution is highly interlinked. Radiationinduced segregation of Cr and existing chromium carbide coverage in irradiated alloy T91 track each other closely. The radiation-induced precipitation of Ni-Si precipitates and RIS of Ni and Si in alloys T91 and HCM12A are likely related. Neither the evolution of these processes nor their coupling is understood under the conditions required for materials performance in fast reactors (temperature range 300-600°C and doses beyond 200 dpa). Further, predictive modeling is not yet possible as models for microstructure evolution must be developed along with experiments to characterize these key processes and provide tools for extrapolation. To extend the range of operation of nuclear fuel cladding and structural materials in advanced nuclear energy and transmutation systems to that required for the fast reactor, the irradiation-induced evolution of the microstructure, microchemistry, and the associated mechanical properties at relevant temperatures and doses must be understood. Predictive modeling relies on an understanding of the physical processes and also on the development of microstructure and microchemical models to describe their evolution under irradiation. This project will focus on modeling microstructural and microchemical evolution of irradiated alloys by performing detailed modeling of such microstructure evolution processes coupled with well-designed in situ experiments that can provide validation and benchmarking to the computer codes. The broad scientific and technical objectives of this proposal are to evaluate the microstructure and microchemical evolution in advanced ferritic/martensitic and oxide dispersion strengthened (ODS) alloys for cladding and duct reactor materials under long-term and elevated temperature irradiation, leading to improved ability to model structural materials performance and lifetime. Specifically, we propose four research thrusts, namely Thrust 1: Identify the formation mechanism and evolution for dislocation loops with Burgers vector of a<100> and determine whether the defect microstructure (predominately dislocation loop/dislocation density) saturates at high dose. Thrust 2: Identify whether a threshold irradiation temperature or dose exists for the nucleation of growing voids that mark the beginning of irradiation-induced swelling, and begin to probe the limits of thermal stability of the tempered Martensitic structure under irradiation. Thrust 3: Evaluate the stability of nanometer sized Y- Ti-O based oxide dispersion strengthened (ODS) particles at high fluence/temperature. Thrust 4: Evaluate the extent to which precipitates form and/or dissolve as a function of irradiation temperature and dose, and how these changes are driven by radiation induced segregation and microchemical evolutions and determined by the initial microstructure.

  8. Updating time-to-failure distributions based on field observations and sensor data.

    SciTech Connect (OSTI)

    Lowder, Kelly S.; Briand, Daniel; Shirah, Donald

    2006-10-01T23:59:59.000Z

    Enterprise level logistics and prognostics and health management (PHM) modeling efforts use reliability focused failure distributions to characterize the probability of failure over the lifetime of a component. This research characterized the Sandia National Laboratories developed combined lifecycle (CMBL) distribution and explored methods for updating this distribution as systems age and new failure data becomes available. The initial results obtained in applying a Bayesian sequential updating methodology to the CMBL distribution shows promise. This research also resulted in the development of a closed-form full life cycle (CFLC) distribution similar to the CMBL distribution but with slightly different, yet commonly recognized, input parameters. Further research is warranted to provide additional theoretical validation of the distributions, complete the updating methods for the CMBL distribution, evaluate a Bayesian updating methodology for the CFLC distribution, and determine which updating methods would be most appropriate for enterprise level logistics and PHM modeling.

  9. Development of Reliability Function and Failure Rate Considering Information of Censored Data

    SciTech Connect (OSTI)

    Kwang-Won Ahn; Yoonik Kim; Chang-Hyun Chung [Seoul National University (Korea, Republic of)

    2002-07-01T23:59:59.000Z

    Generally, there are two methods to estimate reliability of system or component failure in engineering, or survival function of patient death in medicine: 1) parametric and 2) non-parametric methods. The parametric method has been used widely since there is few data on severe accidents in nuclear power plants. However, if we have a lot of data on system failure or patient death, the non-parametric method could be used to estimate reliability or survival function. In this paper we focus on the latter case in which one problem arises in treating the data. The problem is how to reflects efficiently the censoring information into reliability or survival function. In this study, two works have been done: 1) develop the model to reflect censoring information and 2) show how efficient the model is using the Monte-Carlo Simulation. In the WASH-1400 (NUREG-75/014), Failure to Operate of Motor Operated Valves from Nuclear Experience is suggested 1 0{sup -3}/d. The new developed method can estimate closer to the failure rate 1 0{sup -3}/d than the other existing methods. Also the failure rate using the new method satisfies the conservative limit. (authors)

  10. CALCULATED THERMALLY INDUCED DISPLACEMENTS AND STRESSES FOR HEATER EXPERIMENTS AT STRIPA, SWEDEN. LINEAR THEFMOELASTIC MODELS USING CONSTANT MATERIAL PROPERTIES

    E-Print Network [OSTI]

    Chan, T.

    2010-01-01T23:59:59.000Z

    Modeling for variable rock properties and discontinuities5.2.1. Laboratory rock properties 5.2.2. Discontinuities andand Board, M. 1980. "Rock Properties and Their on Thermally

  11. Gearbox Typical Failure Modes, Detection, and Mitigation Methods (Presentation)

    SciTech Connect (OSTI)

    Sheng, S.

    2014-01-01T23:59:59.000Z

    This presentation was given at the AWEA Operations & Maintenance and Safety Seminar and focused on what the typical gearbox failure modes are, how to detect them using detection techniques, and strategies that help mitigate these failures.

  12. Survey of four damage models for concrete.

    SciTech Connect (OSTI)

    Leelavanichkul, Seubpong (University of Utah, Salt Lake City, UT); Brannon, Rebecca Moss (University of Utah, Salt Lake City, UT)

    2009-08-01T23:59:59.000Z

    Four conventional damage plasticity models for concrete, the Karagozian and Case model (K&C), the Riedel-Hiermaier-Thoma model (RHT), the Brannon-Fossum model (BF1), and the Continuous Surface Cap Model (CSCM) are compared. The K&C and RHT models have been used in commercial finite element programs many years, whereas the BF1 and CSCM models are relatively new. All four models are essentially isotropic plasticity models for which 'plasticity' is regarded as any form of inelasticity. All of the models support nonlinear elasticity, but with different formulations. All four models employ three shear strength surfaces. The 'yield surface' bounds an evolving set of elastically obtainable stress states. The 'limit surface' bounds stress states that can be reached by any means (elastic or plastic). To model softening, it is recognized that some stress states might be reached once, but, because of irreversible damage, might not be achievable again. In other words, softening is the process of collapse of the limit surface, ultimately down to a final 'residual surface' for fully failed material. The four models being compared differ in their softening evolution equations, as well as in their equations used to degrade the elastic stiffness. For all four models, the strength surfaces are cast in stress space. For all four models, it is recognized that scale effects are important for softening, but the models differ significantly in their approaches. The K&C documentation, for example, mentions that a particular material parameter affecting the damage evolution rate must be set by the user according to the mesh size to preserve energy to failure. Similarly, the BF1 model presumes that all material parameters are set to values appropriate to the scale of the element, and automated assignment of scale-appropriate values is available only through an enhanced implementation of BF1 (called BFS) that regards scale effects to be coupled to statistical variability of material properties. The RHT model appears to similarly support optional uncertainty and automated settings for scale-dependent material parameters. The K&C, RHT, and CSCM models support rate dependence by allowing the strength to be a function of strain rate, whereas the BF1 model uses Duvaut-Lion viscoplasticity theory to give a smoother prediction of transient effects. During softening, all four models require a certain amount of strain to develop before allowing significant damage accumulation. For the K&C, RHT, and CSCM models, the strain-to-failure is tied to fracture energy release, whereas a similar effect is achieved indirectly in the BF1 model by a time-based criterion that is tied to crack propagation speed.

  13. Optimal adaptive control of cascading power grid failures

    E-Print Network [OSTI]

    Daniel Bienstock

    2010-12-17T23:59:59.000Z

    Dec 17, 2010 ... Abstract: We describe experiments with parallel algorithms for computing adaptive controls for attenuating power grid cascading failures.

  14. Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert O.; Gao, Fei; Sun, Xin

    2012-05-30T23:59:59.000Z

    Experiments show that inter-granular and intra-granular gas bubbles have different growth kinetics which results in heterogeneous gas bubble microstructures in irradiated nuclear fuels. A science-based model predicting the heterogeneous microstructure evolution kinetics is desired, which enables one to study the effect of thermodynamic and kinetic properties of the system on gas bubble microstructure evolution kinetics and morphology, improve the understanding of the formation mechanisms of heterogeneous gas bubble microstructure, and provide the microstructure to macroscale approaches to study their impact on thermo-mechanical properties such as thermo-conductivity, gas release, volume swelling, and cracking. In our previous report 'Mesoscale Benchmark Demonstration, Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing', we developed a phase-field model to simulate the intra-granular gas bubble evolution in a single crystal during post-irradiation thermal annealing. In this work, we enhanced the model by incorporating thermodynamic and kinetic properties at grain boundaries, which can be obtained from atomistic simulations, to simulate fission gas bubble growth kinetics in polycrystalline UO2 fuels. The model takes into account of gas atom and vacancy diffusion, vacancy trapping and emission at defects, gas atom absorption and resolution at gas bubbles, internal pressure in gas bubbles, elastic interaction between defects and gas bubbles, and the difference of thermodynamic and kinetic properties in matrix and grain boundaries. We applied the model to simulate gas atom segregation at grain boundaries and the effect of interfacial energy and gas mobility on gas bubble morphology and growth kinetics in a bi-crystal UO2 during post-irradiation thermal annealing. The preliminary results demonstrate that the model can produce the equilibrium thermodynamic properties and the morphology of gas bubbles at grain boundaries for given grain boundary properties. More validation of the model capability in polycrystalline is underway.

  15. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 12 (2004) 929943 PII: S0965-0393(04)80701-0

    E-Print Network [OSTI]

    Anderson, Peter M.

    Modelling Simul. Mater. Sci. Eng. 12 (2004) 929­943 PII: S0965-0393(04)80701-0 A three-dimensional cellular

  16. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 10 (2002) 119 PII: S0965-0393(02)55385-7

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    Modelling Simul. Mater. Sci. Eng. 10 (2002) 1­19 PII: S0965-0393(02)55385-7 Accuracy and convergence

  17. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 12 (2004) 197204 PII: S0965-0393(04)70548-3

    E-Print Network [OSTI]

    Deymier, Pierre

    Modelling Simul. Mater. Sci. Eng. 12 (2004) 197­204 PII: S0965-0393(04)70548-3 Formation of bound states

  18. Role of seepage forces on hydraulic fracturing and failure patterns

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Role of seepage forces on hydraulic fracturing and failure patterns Alexander Rozhko Thesis September 2007 #12;ii Role of seepage forces on hydraulic fracturing and failure patterns Abstract. The mechanical role of seepage forces on hydraulic fracturing and failure patterns was studied both

  19. LESSONS LEARNED FROM A LANDFILL SLOPE FAILURE INVOLVING

    E-Print Network [OSTI]

    LESSONS LEARNED FROM A LANDFILL SLOPE FAILURE INVOLVING GEOSYTNTHETICS Virginia L. Wilson: Geosynthetics: Lessons Learned from Failures International Geosynthetics Society editors J.P. Giroud, K.L. Soderman and G.P. Raymond November 12, 1998 #12;LESSONS LEARNED FROM A LANDFILL SLOPE FAILURE INVOLVING

  20. Production-Run Software Failure Diagnosis via Hardware Performance Counters

    E-Print Network [OSTI]

    Sheridan, Jennifer

    Production-Run Software Failure Diagnosis via Hardware Performance Counters Joy Arulraj Po and huge financial loss during production runs. Tools that diagnose production-run failures with low is sometimes over 100%, for concurrency-bug failure diagnosis and hence are not suitable for production

  1. NO. ~EV. NO. Failure Modes and Effects Analysis -LRRR

    E-Print Network [OSTI]

    Rathbun, Julie A.

    of the Failure Modes and Effects Analysis (FMEA) is to discover critical failure areas in the LRRR experiment for the critical failure areas. A TM 868 contains the results of a final FMEA for the LRRR experiment. 2. 0 SUMMARY Since an LRRR was successfully deployed on the moon as a part of the Apollo 11 mission, this FMEA

  2. Failure Modes and Effects Analysis 300 Array -LRRR

    E-Print Network [OSTI]

    Rathbun, Julie A.

    of the Failure Modes and Effects Analysis (FMEA) is to discover critical failure areas in a system and to remove failure areas. 1. 2 This memo contains the results of the final FMEA for the 300 Array LRRR experiment was successfully deployed on the moon as a part of the Apollo 11 mission, this FMEA will not dwell in the aspects

  3. Scintillator material

    DOE Patents [OSTI]

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    1994-01-01T23:59:59.000Z

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  4. Scintillator material

    DOE Patents [OSTI]

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    1992-01-01T23:59:59.000Z

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography.

  5. Scintillator material

    DOE Patents [OSTI]

    Anderson, D.F.; Kross, B.J.

    1992-07-28T23:59:59.000Z

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  6. Scintillator material

    DOE Patents [OSTI]

    Anderson, D.F.; Kross, B.J.

    1994-06-07T23:59:59.000Z

    An improved scintillator material comprising cerium fluoride is disclosed. Cerium fluoride has been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to known scintillator materials such as thallium-doped sodium iodide, barium fluoride and bismuth germanate. As a result, cerium fluoride is favorably suited for use as a scintillator material in positron emission tomography. 4 figs.

  7. PDC IC WELD FAILURE EVALUATION AND RESOLUTION

    SciTech Connect (OSTI)

    Korinko, P.; Howard, S.; Maxwell, D.; Fiscus, J.

    2012-04-16T23:59:59.000Z

    During final preparations for start of the PDCF Inner Can (IC) qualification effort, welding was performed on an automated weld system known as the PICN. During the initial weld, using a pedigree canister and plug, a weld defect was observed. The defect resulted in a hole in the sidewall of the canister, and it was observed that the plug sidewall had not been consumed. This was a new type of failure not seen during development and production of legacy Bagless Transfer Cans (FB-Line/Hanford). Therefore, a team was assembled to determine the root cause and to determine if the process could be improved. After several brain storming sessions (MS and T, R and D Engineering, PDC Project), an evaluation matrix was established to direct this effort. The matrix identified numerous activities that could be taken and then prioritized those activities. This effort was limited by both time and resources (the number of canisters and plugs available for testing was limited). A discovery process was initiated to evaluate the Vendor's IC fabrication process relative to legacy processes. There were no significant findings, however, some information regarding forging/anneal processes could not be obtained. Evaluations were conducted to compare mechanical properties of the PDC canisters relative to the legacy canisters. Some differences were identified, but mechanical properties were determined to be consistent with legacy materials. A number of process changes were also evaluated. A heat treatment procedure was established that could reduce the magnetic characteristics to levels similar to the legacy materials. An in-situ arc annealing process was developed that resulted in improved weld characteristics for test articles. Also several tack welds configurations were addressed, it was found that increasing the number of tack welds (and changing the sequence) resulted in decreased can to plug gaps and a more stable weld for test articles. Incorporating all of the process improvements for the actual can welding process, however, did not result in an improved weld geometry. Several possibilities for the lack of positive response exist, some of which are that (1) an insufficient number of test articles were welded under prototypic conditions, (2) the process was not optimized so that significant improvements were observable over the 'noise', and (3) the in-situ arc anneal closed the gap down too much so the can was unable to exhaust pressure ahead of the weld. Several operational and mechanical improvements were identified. The weld clamps were changed to a design consistent with those used in the legacy operations. A helium puff operation was eliminated; it is believed that this operation was the cause of the original weld defect. Also, timing of plug mast movement was found to correspond with weld irregularities. The timing of the movement was changed to occur during weld head travel between tacks. In the end a three sequential tack weld process followed by a pulse weld at the same current and travel speed as was used for the legacy processes was suggested for use during the IC qualification effort. Relative to legacy welds, the PDC IC weld demonstrates greater fluctuation in the region of the weld located between tack welds. However, canister weld response (canister to canister) is consistent and with the aid of the optical mapping system (for targeting the cut position) is considered adequate. DR measurements and METs show the PDC IC welds to have sufficient ligament length to ensure adequate canister pressure/impact capacity and to ensure adequate stub function. The PDC welding process has not been optimized as a result of this effort. Differences remain between the legacy BTC welds and the PDC IC weld, but these differences are not sufficient to prevent resumption of the current PDC IC qualification effort. During the PDC IC qualification effort, a total of 17 cans will be welded and a variety of tests/inspections will be performed. The extensive data collected during that qualification effort should be of a sufficient population to determ

  8. Material-based design computation

    E-Print Network [OSTI]

    Oxman, Neri

    2010-01-01T23:59:59.000Z

    The institutionalized separation between form, structure and material, deeply embedded in modernist design theory, paralleled by a methodological partitioning between modeling, analysis and fabrication, resulted in ...

  9. Sandia National Laboratories: Materials Science

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sandia Participated in AMII to Support American-Made Wind-Turbine Blades On December 3, 2014, in Computational Modeling & Simulation, Energy, Materials Science, News, News &...

  10. Critical Materials:

    Broader source: Energy.gov (indexed) [DOE]

    lighting. 14 (bottom) Criticality ratings of shortlisted raw 76 materials. 15 77 2. Technology Assessment and Potential 78 This section reviews the major trends within...

  11. An optimized Line Sampling method for the estimation of the failure probability of nuclear passive systems

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    system in a Gas-cooled Fast Reactor (GFR) of literature [3]. Keywords: Functional failure probability direction; ii) employing Artificial Neural Network (ANN) regression models as fast-running surrogates, Genetic Algorithm, long-running code, computational cost. 1 Introduction Modern nuclear reactor concepts

  12. An Automated Failure Modes and Effect Analysis Based Visual Matrix Approach to Sensor Selection and

    E-Print Network [OSTI]

    Snooke, Neal

    - prehensive automated Failure Modes and Effects Analysis (FMEA) using qualitative model based reasoning techniques. The automated FMEA pro- vides a comprehensive set of fault­effect rela- tions by qualitative FMEA results in a fault-effect mapping that can be used to investi- gate the diagnosability

  13. Failure Pressure Estimates of Steam Generator Tubes Containing Wear-type Defects

    SciTech Connect (OSTI)

    Yoon-Suk Chang; Jong-Min Kim; Nam-Su Huh; Young-Jin Kim [School of Mechanical Engineering, Sungkyunkwan University (Korea, Republic of); Seong Sik Hwang; Joung-Soo Kim [Korea Atomic Energy Research Institute (Korea, Republic of)

    2006-07-01T23:59:59.000Z

    It is commonly requested that steam generator tubes with defects exceeding 40% of wall thickness in depth should be plugged to sustain all postulated loads with appropriate margin. The critical defect dimensions have been determined based on the concept of plastic instability. This criterion, however, is known to be too conservative for some locations and types of defects. In this context, the accurate failure estimation for steam generator tubes with a defect draws increasing attention. Although several guidelines have been developed and are used for assessing the integrity of defected tubes, most of these guidelines are related to stress corrosion cracking or wall-thinning phenomena. As some of steam generator tubes are also failed due to fretting and so on, alternative failure estimation schemes for relevant defects are required. In this paper, three-dimensional finite element (FE) analyses are carried out under internal pressure condition to simulate the failure behavior of steam generator tubes with different defect configurations; elliptical wastage type, wear scar type and rectangular wastage type defects. Maximum pressures based on material strengths are obtained from more than a hundred FE results to predict the failure of the steam generator tube. After investigating the effect of key parameters such as wastage depth, wastage length and wrap angle, simplified failure estimation equations are proposed in relation to the equivalent stress at the deepest point in wastage region. Comparison of failure pressures predicted according to the proposed estimation scheme with some corresponding burst test data shows good agreement, which provides a confidence in the use of the proposed equations to assess the integrity of steam generator tubes with wear-type defects. (authors)

  14. Fluid-driven deformation of a soft granular material

    E-Print Network [OSTI]

    Christopher W. MacMinn; Eric R. Dufresne; John S. Wettlaufer

    2015-02-24T23:59:59.000Z

    Compressing a porous, fluid-filled material will drive the interstitial fluid out of the pore space, as when squeezing water out of a kitchen sponge. Inversely, injecting fluid into a porous material can deform the solid structure, as when fracturing a shale for natural gas recovery. These poromechanical interactions play an important role in geological and biological systems across a wide range of scales, from the propagation of magma through the Earth's mantle to the transport of fluid through living cells and tissues. The theory of poroelasticity has been largely successful in modeling poromechanical behavior in relatively simple systems, but this continuum theory is fundamentally limited by our understanding of the pore-scale interactions between the fluid and the solid, and these problems are notoriously difficult to study in a laboratory setting. Here, we present a high-resolution measurement of injection-driven poromechanical deformation in a system with granular microsctructure: We inject fluid into a dense, confined monolayer of soft particles and use particle tracking to reveal the dynamics of the multi-scale deformation field. We find that a continuum model based on poroelasticity theory captures certain macroscopic features of the deformation, but the particle-scale deformation field exhibits dramatic departures from smooth, continuum behavior. We observe particle-scale rearrangement and hysteresis, as well as petal-like mesoscale structures that are connected to material failure through spiral shear banding.

  15. Uncertainty Quantification of the Homogeneity of Granular Materials through Discrete Element Modeling and X-Ray Computed Tomography 

    E-Print Network [OSTI]

    Noble, Patrick

    2012-10-19T23:59:59.000Z

    was modeled numerically using the Discrete Element program PFC3D. The resulting microstructure of the numerical sample was compared to the results of the image analysis to determine if the heterogeneity of the sample could be reproduced correctly for use...

  16. The Power of Mesoscale Modeling... Mul$physics mesoscale simula$on provides a powerful tool for designing materials to

    E-Print Network [OSTI]

    Chen, Long-Qing

    , neutronics, geomechanics, reac+ve transport, microstructure modeling, computa+onal fluid in verba+m from Schwen, D., E. Mar/nez, and A. Caro, J. Nuclear Mater (cv) in UO2 fuel. Also shown are the switching func+on h, the order

  17. Journal of Materials Processing Technology 189 (2007) 192198 Modelling of surface finish and tool flank wear in turning

    E-Print Network [OSTI]

    Ozel, Tugrul

    2007-01-01T23:59:59.000Z

    flank wear in turning of AISI D2 steel with ceramic wiper inserts Tugrul ¨Ozela,, Yigit Karpata, Lu (60 HRC) using ceramic wiper (multi-radii) design inserts. Multiple linear regression models. Experimental results indicate that surface roughness Ra values as low as 0.18­0.20 m are attainable with wiper

  18. Diffusion and Rheology in a Model of Glassy Materials R. M. L. Evans, M. E. Cates & P. Sollich \\Lambda

    E-Print Network [OSTI]

    Sollich, Peter

    (foams, emulsions etc.) as well as to conventional glass­forming liquids is discussed. I. INTRODUCTION is Bouchaud's model of glasses [J.­P. Bouchaud, J. Physique I 2 1705 (1992)], as extended to describe)].) We investigate the breakdown, near the glass transition, of the (generalized) Stokes­ Einstein

  19. Probabilistic Failure Analysis for Wound Composite Ceramic Cladding Assembly

    SciTech Connect (OSTI)

    Hemrick, James Gordon [ORNL] [ORNL; Lara-Curzio, Edgar [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    Advanced ceramic matrix composites based on silicon carbide (SiC) are being considered as candidate material systems for nuclear fuel cladding in light water reactors. The SiC composite structure is considered due to its assumed exceptional performance under accident scenarios, where its excellent high-temperature strength and slow reaction kinetics with steam and associated mitigated hydrogen production are desirable. The specific structures of interest consist of a monolithic SiC cylinder surrounded by interphase-coated SiC woven fibers in a tubular form and infiltrated with SiC. Additional SiC coatings on the outermost surface of the assembly are also being considered to prevent hydrothermal corrosion of the fibrous structure. The inner monolithic cylinder is expected to provide a hermetic seal to contain fission products under normal conditions. While this approach offers the promise of higher burn-up rates and safer behavior in the case of LOCA events, the reliability of such structures must be demonstrated in advance. Therefore, a probability failure analysis study was performed of such monolithic-composite hybrid structures to determine the feasibility of these design concepts. This analysis will be used to predict the future performance of candidate systems in an effort to determine the feasibility of these design concepts and to make future recommendations regarding materials selection.

  20. NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71-10 / p. 1 of 115 FAILURE MODES AND EFFECTS ANALYSIS

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71-10 / p. 1 of 115 NSTX FAILURE MODES AND EFFECTS ANALYSIS (FMEA) Revision 10 Dated: November 2014 Prepared By: Name/WBS Signature Name: ________________________________________________ Ron Strykowsky, NSTX Upgrade Project Manager #12;NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71

  1. Common-Cause Failure Analysis for Reactor Protection System Reliability Studies

    SciTech Connect (OSTI)

    Gentillon, C.; Rasmuson, D.; Eide, S.; Wierman, T.

    1999-08-01T23:59:59.000Z

    Analyses were performed of the safety-related performance of the reactor protection system (RPS) at U.S. Westinghouse and General Electric commercial reactors during the period 1984 through 1995. RPS operational data from these reactors were collected from the Nuclear Plant Reliability Data System (NPRDS) and Licensee Event Reports (LER). The common-cause failure (CCF) modeling in the fault trees developed for these studies and the analysis and use of common-cause failure data were sophisticated, state-of-the-art efforts. The overall CCF effort helped to test and expand the limits of the U.S. Nuclear Regulatory Commission's CCF methodology.

  2. Materials for solid state lighting

    SciTech Connect (OSTI)

    Johnson, S.G.; Simmons, J.A.

    2002-03-26T23:59:59.000Z

    Dramatic improvement in the efficiency of inorganic and organic light emitting diodes (LEDs and OLEDs) within the last decade has made these devices viable future energy efficient replacements for current light sources. However, both technologies must overcome major technical barriers, requiring significant advances in material science, before this goal can be achieved. Attention will be given to each technology associated with the following major areas of material research: (1) material synthesis, (2) process development, (3) device and defect physics, and (4) packaging. The discussion on material synthesis will emphasize the need for further development of component materials, including substrates and electrodes, necessary for improving device performance. The process technology associated with the LEDs and OLEDs is very different, but in both cases it is one factor limiting device performance. Improvements in process control and methodology are expected to lead to additional benefits of higher yield, greater reliability and lower costs. Since reliability and performance are critical to these devices, an understanding of the basic physics of the devices and device failure mechanisms is necessary to effectively improve the product. The discussion will highlight some of the more basic material science problems remaining to be solved. In addition, consideration will be given to packaging technology and the need for the development of novel materials and geometries to increase the efficiencies and reliability of the devices. The discussion will emphasize the performance criteria necessary to meet lighting applications, in order to illustrate the gap between current status and market expectations for future product.

  3. Cermet materials

    DOE Patents [OSTI]

    Kong, Peter C. (Idaho Falls, ID)

    2008-12-23T23:59:59.000Z

    A self-cleaning porous cermet material, filter and system utilizing the same may be used in filtering particulate and gaseous pollutants from internal combustion engines having intermetallic and ceramic phases. The porous cermet filter may be made from a transition metal aluminide phase and an alumina phase. Filler materials may be added to increase the porosity or tailor the catalytic properties of the cermet material. Additionally, the cermet material may be reinforced with fibers or screens. The porous filter may also be electrically conductive so that a current may be passed therethrough to heat the filter during use. Further, a heating element may be incorporated into the porous cermet filter during manufacture. This heating element can be coated with a ceramic material to electrically insulate the heating element. An external heating element may also be provided to heat the cermet filter during use.

  4. Composite material

    DOE Patents [OSTI]

    Hutchens, Stacy A. (Knoxville, TN); Woodward, Jonathan (Solihull, GB); Evans, Barbara R. (Oak Ridge, TN); O'Neill, Hugh M. (Knoxville, TN)

    2012-02-07T23:59:59.000Z

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  5. A model for prediction of the damage and effects of explosive projectiles on helicopter composite material rotor blades

    E-Print Network [OSTI]

    Mikel, Tilden Newton

    1982-01-01T23:59:59.000Z

    and are used. to determine the blade's ability to survive continued flight loading. The model was developed to be a preliminary design analysis tool and can easily be executed on a small desktop computer. ACXNOMLEDGHENT I extend by most sincere thanks to Dr.... The funding for the ballistic tests conducted during this research was provided 'by Bell Helicopter Textron, Inc. , Fort cnorth, Texs s, TABLE OF CONTENTS Page ABSTRACT. . . . . ~ ~ ~ ~ ~ ~ ~ ~ ACKNOWLEDGMENT TABLE OF CONTENTS LIST OF TABLES. LIST...

  6. Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation

    SciTech Connect (OSTI)

    Abercrombie, Robert K [ORNL] [ORNL; Schlicher, Bob G [ORNL] [ORNL; Sheldon, Frederick T [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the Advanced Metering Infrastructure (AMI) functional domain which the National Electric Sector Cyber security Organization Resource (NESCOR) working group has currently documented 29 failure scenarios. The strategy for the game was developed by analyzing five electric sector representative failure scenarios contained in the AMI functional domain. From these five selected scenarios, we characterize them into three specific threat categories affecting confidentiality, integrity and availability (CIA). The analysis using our ABGT simulation demonstrates how to model the AMI functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the AMI network with respect to CIA.

  7. Failure Analysis of a Complex Learning Framework Incorporating Multi-Modal and Semi-Supervised Learning

    SciTech Connect (OSTI)

    Pullum, Laura L [ORNL; Symons, Christopher T [ORNL

    2011-01-01T23:59:59.000Z

    Machine learning is used in many applications, from machine vision to speech recognition to decision support systems, and is used to test applications. However, though much has been done to evaluate the performance of machine learning algorithms, little has been done to verify the algorithms or examine their failure modes. Moreover, complex learning frameworks often require stepping beyond black box evaluation to distinguish between errors based on natural limits on learning and errors that arise from mistakes in implementation. We present a conceptual architecture, failure model and taxonomy, and failure modes and effects analysis (FMEA) of a semi-supervised, multi-modal learning system, and provide specific examples from its use in a radiological analysis assistant system. The goal of the research described in this paper is to provide a foundation from which dependability analysis of systems using semi-supervised, multi-modal learning can be conducted. The methods presented provide a first step towards that overall goal.

  8. Impact of defects on the electrical transport, optical properties and failure mechanisms of GaN nanowires.

    SciTech Connect (OSTI)

    Armstrong, Andrew M.; Aubry, Sylvie; Shaner, Eric Arthur; Siegal, Michael P.; Li, Qiming; Jones, Reese E.; Westover, Tyler; Wang, George T.; Zhou, Xiao Wang; Talin, Albert Alec; Bogart, Katherine Huderle Andersen; Harris, C. Thomas; Huang, Jian Yu

    2010-09-01T23:59:59.000Z

    We present the results of a three year LDRD project that focused on understanding the impact of defects on the electrical, optical and thermal properties of GaN-based nanowires (NWs). We describe the development and application of a host of experimental techniques to quantify and understand the physics of defects and thermal transport in GaN NWs. We also present the development of analytical models and computational studies of thermal conductivity in GaN NWs. Finally, we present an atomistic model for GaN NW electrical breakdown supported with experimental evidence. GaN-based nanowires are attractive for applications requiring compact, high-current density devices such as ultraviolet laser arrays. Understanding GaN nanowire failure at high-current density is crucial to developing nanowire (NW) devices. Nanowire device failure is likely more complex than thin film due to the prominence of surface effects and enhanced interaction among point defects. Understanding the impact of surfaces and point defects on nanowire thermal and electrical transport is the first step toward rational control and mitigation of device failure mechanisms. However, investigating defects in GaN NWs is extremely challenging because conventional defect spectroscopy techniques are unsuitable for wide-bandgap nanostructures. To understand NW breakdown, the influence of pre-existing and emergent defects during high current stress on NW properties will be investigated. Acute sensitivity of NW thermal conductivity to point-defect density is expected due to the lack of threading dislocation (TD) gettering sites, and enhanced phonon-surface scattering further inhibits thermal transport. Excess defect creation during Joule heating could further degrade thermal conductivity, producing a viscous cycle culminating in catastrophic breakdown. To investigate these issues, a unique combination of electron microscopy, scanning luminescence and photoconductivity implemented at the nanoscale will be used in concert with sophisticated molecular-dynamics calculations of surface and defect-mediated NW thermal transport. This proposal seeks to elucidate long standing material science questions for GaN while addressing issues critical to realizing reliable GaN NW devices.

  9. Synthesis of oligomeric models of coal-derived materials for use with GPC calibration. Quarterly report, June-August 1982. [Gel permeation chromatography

    SciTech Connect (OSTI)

    Baltisberger, R J; Jones, M B

    1982-09-01T23:59:59.000Z

    One important facet of the characterization of coal-derived materials is that of molecular weight determination. Number average molecular weight is usually obtained by vapor pressure osmometry measurements. However, no satisfactory method is available for determining weight average molecular weights. The latter values are useful in predicting rheological properties. Gel permeation chromatography (GPC) is a technique which should be most readily adaptable for this measurement. The other techniques of ultracentrifugation and light scattering are not as readily available as GPC. At this time, satisfactory GPC calibration standards which possess chemical structures similar to coal derived mterials are non-existent. The purpose of this study is to develop a useful set of GPC calibration standards for asphaltene and preaspaltene analyses. Our previous results suggest models in which coal derived preasphaltenes and asphaltenes are composed of oligomeric aromatic ethers of both diaryl and furan types. We plan to synthesize a series of model oligomers that are in agreement with the average structural formulas of some selected coal preasphaltenes as determined by pmr, elemental analyses and various oxygen derivatization procedures. These model compounds will be tested for use as calibration standards for both high pressure gel permeation chromatographic and vapor pressure osmometric procedures. Their response and retention times will be compared with coal preasphaltenes to determine the suitability of the model compounds as calibration standards.

  10. Deformation-Twin-Induced Grain Boundary Failure

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C. MIllett; Michael Tonks; Bulent Biner

    2012-01-01T23:59:59.000Z

    This work presents a mechanism of deformation-twin-induced grain boundary failure, and demonstrates the mechanism using molecular dynamics simulations. Deformation twinning is observed as the dominant mechanism during tensile deformation of columnar nanocrystalline body-centered cubic Mo. As a twin approaches a grain boundary, local stress concentration develops due to the incompatible plastic deformations in the two neighboring grains. The magnitude of the stress concentration increases as the twin widens, leading to grain boundary cracking by nucleation and coalescence of microcracks/voids.

  11. Reduce Steam Trap Failures at Chambers Works

    E-Print Network [OSTI]

    Kouba, C.

    Maintenance Mechanic), Rick Ragsdale (Fluor), Joyce Finkle (PC), Denis P Humphreys (Fluoroproducts), Jack Hemmert, Charlie Brown 10/20/2010 2 Steam trap failures are nothing new Steam trap programs are nothing new WHAT makes this program have such a huge... impact and How is it sustainable HOW we went about finding a solution What do you have learn from this 10/20/2010 3 Six Sigma Methodology was KEY to success Savings: $1MM annualized in only 6 months! 10/20/2010 4Define: Project CTQ?s Customer...

  12. Cascade Failures from Distributed Generation in Power Grids

    E-Print Network [OSTI]

    Scala, Antonio; Scoglio, Caterina

    2012-01-01T23:59:59.000Z

    Power grids are nowadays experiencing a transformation due to the introduction of Distributed Generation based on Renewable Sources. At difference with classical Distributed Generation, where local power sources mitigate anomalous user consumption peaks, Renewable Sources introduce in the grid intrinsically erratic power inputs. By introducing a simple schematic (but realistic) model for power grids with stochastic distributed generation, we study the effects of erratic sources on the robustness of several IEEE power grid test networks with up to 2000 buses. We find that increasing the penetration of erratic sources causes the grid to fail with a sharp transition. We compare such results with the case of failures caused by the natural increasing power demand.

  13. Argonne National Laboratory Investigates Premature Bearing Failures...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of this investigation were recently published in the peer-reviewed journal Wear, titled "Material Wear and Fatigue in Wind Turbine Systems" and presented at the corresponding Wear...

  14. Analysis of HP2 nozzle assembly failure of a gas turbine

    SciTech Connect (OSTI)

    Anto, P.F.; Singh, S.K. [Oil and Natural Gas Corp. Ltd., Maharashtra (India). Inst. of Engineering and Ocean Technology

    1998-12-31T23:59:59.000Z

    The HP2 nozzle assembly of one of the process platform failed by plastic deformation of the vanes after an operating life of 20,000 hours. The vanes were made of alloy 31. The failed vanes were subjected to detailed failure analysis by conducting metallography, hardness testing, energy dispersive spectroscopy, x-ray diffraction and electron probe micro analysis. The phenomenon of sulfidation and catastrophic oxidation was not observed in the material. It was found that the material had undergone high temperature oxidation. The material did not show any signs of creep damage and phase growth preferential attack of carbides was identified. The alloy exhibited loss of hardness at the aerofoil surface which aided material erosion and degradation of alloy strength properties. Various thermal barrier coatings to prevent high temperature oxidation were studied.

  15. Disruption of POF1B binding to nonmuscle actin filaments is associated with premature ovarian failure.

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    premature ovar- ian failure: analysis of 71 cases. Humanalysis of two candidate genes for premature ovarian failure,

  16. Material Symbols 

    E-Print Network [OSTI]

    Clark, Andy

    2006-01-01T23:59:59.000Z

    What is the relation between the material, conventional symbol structures that we encounter in the spoken and written word, and human thought? A common assumption, that structures a wide variety of otherwise competing ...

  17. Complex Materials

    ScienceCinema (OSTI)

    Cooper, Valentino

    2014-05-23T23:59:59.000Z

    Valentino Cooper uses some of the world's most powerful computing to understand how materials work at subatomic levels, studying breakthroughs such as piezoelectrics, which convert mechanical stress to electrical energy.

  18. MULTISCALE PHENOMENA IN MATERIALS

    SciTech Connect (OSTI)

    A. BISHOP

    2000-09-01T23:59:59.000Z

    This project developed and supported a technology base in nonequilibrium phenomena underpinning fundamental issues in condensed matter and materials science, and applied this technology to selected problems. In this way the increasingly sophisticated synthesis and characterization available for classes of complex electronic and structural materials provided a testbed for nonlinear science, while nonlinear and nonequilibrium techniques helped advance our understanding of the scientific principles underlying the control of material microstructure, their evolution, fundamental to macroscopic functionalities. The project focused on overlapping areas of emerging thrusts and programs in the Los Alamos materials community for which nonlinear and nonequilibrium approaches will have decisive roles and where productive teamwork among elements of modeling, simulations, synthesis, characterization and applications could be anticipated--particularly multiscale and nonequilibrium phenomena, and complex matter in and between fields of soft, hard and biomimetic materials. Principal topics were: (i) Complex organic and inorganic electronic materials, including hard, soft and biomimetic materials, self-assembly processes and photophysics; (ii) Microstructure and evolution in multiscale and hierarchical materials, including dynamic fracture and friction, dislocation and large-scale deformation, metastability, and inhomogeneity; and (iii) Equilibrium and nonequilibrium phases and phase transformations, emphasizing competing interactions, frustration, landscapes, glassy and stochastic dynamics, and energy focusing.

  19. MATERIAL TRACKING USING LANMAS

    SciTech Connect (OSTI)

    Armstrong, F.

    2010-06-07T23:59:59.000Z

    LANMAS is a transaction-based nuclear material accountability software product developed to replace outdated and legacy accountability systems throughout the DOE. The core underlying purpose of LANMAS is to track nuclear materials inventory and report transactions (movement, mixing, splitting, decay, etc.) to the Nuclear Materials Management and Safeguards System (NMMSS). While LANMAS performs those functions well, there are many additional functions provided by the software product. As a material is received onto a site or created at a site, its entire lifecycle can be tracked in LANMAS complete to its termination of safeguards. There are separate functions to track material movements between and within material balance areas (MBAs). The level of detail for movements within a MBA is configurable by each site and can be as high as a site designation or as detailed as building/room/rack/row/position. Functionality exists to track the processing of materials, either as individual items or by modeling a bulk process as an individual item to track inputs and outputs from the process. In cases where sites have specialized needs, the system is designed to be flexible so that site specific functionality can be integrated into the product. This paper will demonstrate how the software can be used to input material into an account and track it to its termination of safeguards.

  20. Defense against common mode failures in protection system design

    SciTech Connect (OSTI)

    Wyman, R.H.; Johnson, G.L.

    1997-08-27T23:59:59.000Z

    The introduction of digital instrumentation and control into reactor safety systems creates a heightened concern about common-mode failure. This paper discusses the concern and methods to cope with the concern. Common-mode failures have been a ``fact-of-life`` in existing systems. The informal introduction of defense-in-depth and diversity (D-in-D&D)-coupled with the fact that hardware common-mode failures are often distributed in time-has allowed systems to deal with past common-mode failures. However, identical software operating in identical redundant systems presents the potential for simultaneous failure. Consequently, the use of digital systems raises the concern about common-mode failure to a new level. A more methodical approach to mitigating common-mode failure is needed to address these concerns. Purposeful introduction of D-in-D&D has been used as a defense against common-mode failure in reactor protection systems. At least two diverse systems are provided to mitigate any potential initiating event. Additionally, diverse displays and controls are provided to allow the operator to monitor plant status and manually initiate engineered safety features. A special form of conimon-mode failure analysis called ``defense-in-depth and diversity analysis`` has been developed to identify possible conimon-mode failure vulnerabilities in digital systems. An overview of this analysis technique is provided.

  1. Materials Degradation in Light Water Reactors: Life After 60,???

    SciTech Connect (OSTI)

    Busby, Jeremy T [ORNL; Nanstad, Randy K [ORNL; Stoller, Roger E [ORNL; Feng, Zhili [ORNL; Naus, Dan J [ORNL

    2008-04-01T23:59:59.000Z

    Nuclear reactors present a very harsh environment for components service. Components within a reactor core must tolerate high temperature water, stress, vibration, and an intense neutron field. Degradation of materials in this environment can lead to reduced performance, and in some cases, sudden failure. A recent EPRI-led study interviewed 47 US nuclear utility executives to gauge perspectives on long-term operation of nuclear reactors. Nearly 90% indicated that extensions of reactor lifetimes to beyond 60 years were likely. When polled on the most challenging issues facing further life extension, two-thirds cited plant reliability as the key issue with materials aging and cable/piping as the top concerns for plant reliability. Materials degradation within a nuclear power plant is very complex. There are many different types of materials within the reactor itself: over 25 different metal alloys can be found with can be found within the primary and secondary systems, not to mention the concrete containment vessel, instrumentation and control, and other support facilities. When this diverse set of materials is placed in the complex and harsh environment coupled with load, degradation over an extended life is indeed quite complicated. To address this issue, the USNRC has developed a Progressive Materials Degradation Approach (NUREG/CR-6923). This approach is intended to develop a foundation for appropriate actions to keep materials degradation from adversely impacting component integrity and safety and identify materials and locations where degradation can reasonably be expected in the future. Clearly, materials degradation will impact reactor reliability, availability, and potentially, safe operation. Routine surveillance and component replacement can mitigate these factors, although failures still occur. With reactor life extensions to 60 years or beyond or power uprates, many components must tolerate the reactor environment for even longer times. This may increase susceptibility for most components and may introduce new degradation modes. While all components (except perhaps the reactor vessel) can be replaced, it may not be economically favorable. Therefore, understanding, controlling, and mitigating materials degradation processes are key priorities for reactor operation, power uprate considerations, and life extensions. This document is written to give an overview of some of the materials degradation issues that may be key for extend reactor service life. A detailed description of all the possible forms of degradation is beyond the scope of this short paper and has already been described in other documents (for example, the NUREG/CR-6923). The intent of this document is to present an overview of current materials issues in the existing reactor fleet and a brief analysis of the potential impact of extending life beyond 60 years. Discussion is presented in six distinct areas: (1) Reactor pressure vessel; (2) Reactor core and primary systems; (3) Reactor secondary systems; (4) Weldments; (5) Concrete; and (6) Modeling and simulations. Following each of these areas, some research thrust directions to help identify and mitigate lifetime extension issues are proposed. Note that while piping and cabling are important for extended service, these components are discussed in more depth in a separate paper. Further, the materials degradation issues associated with fuel cladding and fuel assemblies are not discussed in this section as these components are replaced periodically and will not influence the overall lifetime of the reactor.

  2. Nuclear fuel elements made from nanophase materials

    DOE Patents [OSTI]

    Heubeck, Norman B. (Schenectady, NY)

    1998-01-01T23:59:59.000Z

    A nuclear reactor core fuel element is composed of nanophase high temperature materials. An array of the fuel elements in rod form are joined in an open geometry fuel cell that preferably also uses such nanophase materials for the cell structures. The particular high temperature nanophase fuel element material must have the appropriate mechanical characteristics to avoid strain related failure even at high temperatures, in the order of about 3000.degree. F. Preferably, the reactor type is a pressurized or boiling water reactor and the nanophase material is a high temperature ceramic or ceramic composite. Nanophase metals, or nanophase metals with nanophase ceramics in a composite mixture, also have desirable characteristics, although their temperature capability is not as great as with all-ceramic nanophase material. Combinations of conventional or nanophase metals and conventional or nanophase ceramics can be employed as long as there is at least one nanophase material in the composite. The nuclear reactor so constructed has a number of high strength fuel particles, a nanophase structural material for supporting a fuel rod at high temperature, a configuration to allow passive cooling in the event of a primary cooling system failure, an ability to retain a coolable geometry even at high temperatures, an ability to resist generation of hydrogen gas, and a configuration having good nuclear, corrosion, and mechanical characteristics.

  3. Nuclear fuel elements made from nanophase materials

    DOE Patents [OSTI]

    Heubeck, N.B.

    1998-09-08T23:59:59.000Z

    A nuclear reactor core fuel element is composed of nanophase high temperature materials. An array of the fuel elements in rod form are joined in an open geometry fuel cell that preferably also uses such nanophase materials for the cell structures. The particular high temperature nanophase fuel element material must have the appropriate mechanical characteristics to avoid strain related failure even at high temperatures, in the order of about 3000 F. Preferably, the reactor type is a pressurized or boiling water reactor and the nanophase material is a high temperature ceramic or ceramic composite. Nanophase metals, or nanophase metals with nanophase ceramics in a composite mixture, also have desirable characteristics, although their temperature capability is not as great as with all-ceramic nanophase material. Combinations of conventional or nanophase metals and conventional or nanophase ceramics can be employed as long as there is at least one nanophase material in the composite. The nuclear reactor so constructed has a number of high strength fuel particles, a nanophase structural material for supporting a fuel rod at high temperature, a configuration to allow passive cooling in the event of a primary cooling system failure, an ability to retain a coolable geometry even at high temperatures, an ability to resist generation of hydrogen gas, and a configuration having good nuclear, corrosion, and mechanical characteristics. 5 figs.

  4. Failure Forewarning in NPP Equipment NERI2000-109 Final Project Report

    SciTech Connect (OSTI)

    Hively, LM

    2004-03-26T23:59:59.000Z

    The objective of this project is forewarning of machine failures in critical equipment at next-generation nuclear power plants (NPP). Test data were provided by two collaborating institutions: Duke Engineering and Services (first project year), and the Pennsylvania State University (Applied Research Laboratory) during the second and third project years. New nonlinear methods were developed and applied successfully to extract forewarning trends from process-indicative, time-serial data for timely, condition-based maintenance. Anticipation of failures in critical equipment at next-generation NPP will improve the scheduling of maintenance activities to minimize safety concerns, unscheduled non-productive downtime, and collateral damage due to unexpected failures. This approach provides significant economic benefit, and is expected to improve public acceptance of nuclear power. The approach is a multi-tiered, model-independent, and data-driven analysis that uses ORNL's novel nonlinear method to extract forewarning of machine failures from appropriate data. The first tier of the analysis provides a robust choice for the process-indicative data. The second tier rejects data of inadequate quality. The third tier removes signal artifacts that would otherwise confound the analysis, while retaining the relevant nonlinear dynamics. The fourth tier converts the artifact-filtered time-serial data into a geometric representation, that is then transformed to a discrete distribution function (DF). This method allows for noisy, finite-length datasets. The fifth tier obtains dissimilarity measures (DM) between the nominal-state DF and subsequent test-state DFs. Forewarning of a machine failure is indicated by several successive occurrences of the DM above a threshold, or by a statistically significant trend in the DM. This paradigm yields robust nonlinear signatures of degradation and its progression, allowing earlier and more accurate detection of the machine failure.

  5. Impact of Fuel Failure on Criticality Safety of Used Nuclear Fuel

    SciTech Connect (OSTI)

    Marshall, William BJ J [ORNL] [ORNL; Wagner, John C [ORNL] [ORNL

    2012-01-01T23:59:59.000Z

    Commercial used nuclear fuel (UNF) in the United States is expected to remain in storage for considerably longer periods than originally intended (e.g., <40 years). Extended storage (ES) time and irradiation of nuclear fuel to high-burnup values (>45 GWd/t) may increase the potential for fuel failure during normal and accident conditions involving storage and transportation. Fuel failure, depending on the severity, can result in changes to the geometric configuration of the fuel, which has safety and regulatory implications. The likelihood and extent of fuel reconfiguration and its impact on the safety of the UNF is not well understood. The objective of this work is to assess and quantify the impact of fuel reconfiguration due to fuel failure on criticality safety of UNF in storage and transportation casks. This effort is primarily motivated by concerns related to the potential for fuel degradation during ES periods and transportation following ES. The criticality analyses consider representative UNF designs and cask systems and a range of fuel enrichments, burnups, and cooling times. The various failed-fuel configurations considered are designed to bound the anticipated effects of individual rod and general cladding failure, fuel rod deformation, loss of neutron absorber materials, degradation of canister internals, and gross assembly failure. The results quantify the potential impact on criticality safety associated with fuel reconfiguration and may be used to guide future research, design, and regulatory activities. Although it can be concluded that the criticality safety impacts of fuel reconfiguration during transportation subsequent to ES are manageable, the results indicate that certain configurations can result in a large increase in the effective neutron multiplication factor, k{sub eff}. Future work to inform decision making relative to which configurations are credible, and therefore need to be considered in a safety evaluation, is recommended.

  6. Dynamic leakage of faults during differential depletion: Theory, models, and examples from the Niger delta

    SciTech Connect (OSTI)

    Watts, N.L.; Kaars Sijpestein, C.H.; Osai, L.N.; Okoli, O.C. (Shell Petroleum Development Co. of Nigeria, Lagos (Nigeria))

    1991-08-01T23:59:59.000Z

    Previous studies of fault sealing have addressed possible fault leakage during secondary migration due to the effects of increased hydrocarbon-water capillary pressure, fracturing, or small-scale incremental fault movements. Of equal importance to production geologists is the failure and leakage of faults during field development due to differential depletion of adjacent fault blocks. This paper examines the unique problems associated with this dynamic leakage of faults. It is theoretically shown that the fault sealing mechanism, and the extent of the seal, directly influences the failure process which in turn results in a variety of favorable and unfavorable effects on field development. The qualitative models give considerable insight into such aspects as oil-column expansion and resaturation losses, interfault block aquifer support (with important implications to material balance calculations), possible leakage or spillage of oil across faults, and potential fault failure during (re)injection projects. Examples of dynamic fault leakage are presented from selected fields of the Niger delta.

  7. Hardfacing material

    DOE Patents [OSTI]

    Branagan, Daniel J. (Iona, ID)

    2012-01-17T23:59:59.000Z

    A method of producing a hard metallic material by forming a mixture containing at least 55% iron and at least one of boron, carbon, silicon and phosphorus. The mixture is formed into an alloy and cooled to form a metallic material having a hardness of greater than about 9.2 GPa. The invention includes a method of forming a wire by combining a metal strip and a powder. The metal strip and the powder are rolled to form a wire containing at least 55% iron and from two to seven additional elements including at least one of C, Si and B. The invention also includes a method of forming a hardened surface on a substrate by processing a solid mass to form a powder, applying the powder to a surface to form a layer containing metallic glass, and converting the glass to a crystalline material having a nanocrystalline grain size.

  8. Development of an Extreme Environment Materials Research Facility at Princeton

    SciTech Connect (OSTI)

    Cohen, A B; Tully, C G; Austin, R; Calaprice, F; McDonald, K; Ascione, G; Baker, G; Davidson, R; Dudek, L; Grisham, L; Kugel, H; Pagdon, K; Stevenson, T; Woolley, R

    2010-11-17T23:59:59.000Z

    The need for a fundamental understanding of material response to a neutron and/or high heat flux environment can yield development of improved materials and operations with existing materials. Such understanding has numerous applications in fields such as nuclear power (for the current fleet and future fission and fusion reactors), aerospace, and other research fields (e.g., high-intensity proton accelerator facilities for high energy physics research). A proposal has been advanced to develop a facility for testing various materials under extreme heat and neutron exposure conditions at Princeton. The Extreme Environment Materials Research Facility comprises an environmentally controlled chamber (48 m^3) capable of high vacuum conditions, with extreme flux beams and probe beams accessing a central, large volume target. The facility will have the capability to expose large surface areas (1 m^2) to 14 MeV neutrons at a fluence in excess of 10^13 n/s. Depending on the operating mode. Additionally beam line power on the order of 15-75 MW/m2 for durations of 1-15 seconds are planned... The multi-second duration of exposure can be repeated every 2-10 minutes for periods of 10-12 hours. The facility will be housed in the test cell that held the Tokamak Fusion Test Reactor (TFTR), which has the desired radiation and safety controls as well as the necessary loading and assembly infrastructure. The facility will allow testing of various materials to their physical limit of thermal endurance and allow for exploring the interplay between radiation-induced embrittlement, swelling and deformation of materials, and the fatigue and fracturing that occur in response to thermal shocks. The combination of high neutron energies and intense fluences will enable accelerated time scale studies. The results will make contributions for refining predictive failure modes (modeling) in extreme environments, as well as providing a technical platform for the development of new alloys, new materials, and the investigation of repair mechanisms. Effects on materials will be analyzed with in situ beam probes and instrumentation as the target is exposed to radiation, thermal fluxes and other stresses. Photon and monochromatic neutron fluxes, produced using a variable-energy (4-45 MeV) electron linac and the highly asymmetric electron-positron collisions technique used in high-energy physics research, can provide non-destructive, deep-penetrating structural analysis of materials while they are undergoing testing. The same beam lines will also be able to generate neutrons from photonuclear interactions using existing Bremsstrahlung and positrons on target quasi-monochromatic gamma rays. Other diagnostics will include infrared cameras, residual gas analyzer (RGA), and thermocouples; additional diagnostic capability will be added.

  9. Journal of Nuclear Materials 187(1992) 1-31 North-Holland

    E-Print Network [OSTI]

    Raffray, A. René

    1992-01-01T23:59:59.000Z

    tritium inventories 1. Introduction Interest in the use of solid lithium-based materials as tritium/multiplier thermomechanical behavior Corrosion and mass transfer Structural response and failure modes in fusion environment

  10. "Tablet-level Origin of Toughening in Abalone Shells and Translation to Synthetic Nanocomposite Materials"

    E-Print Network [OSTI]

    Ghosh, Somnath

    bio-inspired nanocomposites. In particular, the development of a nacre-like material, fabricated by 3D printing and exhibiting similar failure modes, will be presented. Then, I will discuss the nanomechanics

  11. Size-dependent mechanical properties of beta-structures in protein materials

    E-Print Network [OSTI]

    Keten, Sinan

    2010-01-01T23:59:59.000Z

    Protein materials such as spider silk can be exceptionally strong, and they can stretch tremendously before failure. Notably, silks are made entirely of proteins, which owe their structure and stability to weak molecular ...

  12. A Methodology Supporting the Risk-Informed Management of Materials Degradation

    SciTech Connect (OSTI)

    Unwin, Stephen D.; Lowry, Peter P.; Toyooka, Michael Y.

    2011-07-28T23:59:59.000Z

    This paper describes a methodology for the synthesis of materials degradation data with nuclear power plant service data to estimate the long-term failure rates of passive components.

  13. Wind Turbine Gearbox Failure Modes - A Brief (Presentation)

    SciTech Connect (OSTI)

    Sheng, S.; McDade, M.; Errichello, R.

    2011-10-01T23:59:59.000Z

    Wind turbine gearboxes are not always meeting 20-year design life. Premature failure of gearboxes increases cost of energy, turbine downtime, unplanned maintenance, gearbox replacement and rebuild, and increased warranty reserves. The problem is widespread, affects most Original Equipment Manufacturers, and is not caused by manufacturing practices. There is a need to improve gearbox reliability and reduce turbine downtime. The topics of this presentation are: GRC (Gearbox Reliability Collaborative) technical approach; Gearbox failure database; Recorded incidents summary; Top failure modes for bearings; Top failure modes for gears; GRC test gearbox; Bearing nomenclature; Test history; Real damage; Gear sets; Bearings; Observations; and Summary. 5 refs.

  14. Poroelastic damage rheology: Dilation, compaction, and failure of rocks

    E-Print Network [OSTI]

    Lyakhovsky, Vladimir

    Poroelastic damage rheology: Dilation, compaction, and failure of rocks Yariv Hamiel Institute December 2004; Published 26 January 2005. Hamiel, Y., V. Lyakhovsky, and A. Agnon (2005), Poroelastic

  15. adhesive failure pattern: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    adhesives is a subject of great importance Mahadevan, L. 2 Dynamical failure of Turing patterns Condensed Matter (arXiv) Summary: The emergence of stable disordered patterns...

  16. GROUND PLANE INSULATION FAILURE IN THE FIRST TPC SUPERCONDUCTING COIL

    E-Print Network [OSTI]

    Green, M.A.

    2010-01-01T23:59:59.000Z

    FAILURE IN THE FIRST TPC SUPERCONDUCTING COIL M. A. Green,Time Projection Cnamber) thin superconducting solenoid. Theand breakage of the superconductor. The UPA circuit melted

  17. Fundamental Approach to Electrode Fabrication and Failure Analysis

    Broader source: Energy.gov (indexed) [DOE]

    Fundamental Approach to Electrode Fabrication and Failure Analysis Vince Battaglia LBNL May 11, 2011 This presentation does not contain any proprietary, confidential, or otherwise...

  18. applying failure mode: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    diagrams (PFDs), hierarchical task analysis (HTA), failure mode and effects analysis (FMEA), systematic human error reduction (more) Griffin, Melissa Corinne 2010-01-01 3...

  19. Investigations of Bearing Failures Associated with White Etching...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Bearing Failures Associated with White Etching Areas (irWEAs) in Wind Turbine Gearboxes Presented by Bob Errichello of GEARTECH at the Wind Turbine Tribology...

  20. antihypertensive trial failures: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    GEOSYNTHETICS Engineering Websites Summary: failure involving a reinforced geosynthetic clay liner in a sedimentation pond at a waste containment liners to hydrate during on-site...