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Sample records for material failure model

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

    E-Print Network [OSTI]

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

    2006-01-01

    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 ...

  2. Modeling Different Failure Mechanisms in Metals 

    E-Print Network [OSTI]

    Zhang, Liang

    2012-02-14

    Material failure plays an important role in human life. By investigating the failure mechanisms, people can more precisely predict the failure conditions to develop new products, to enhance product performances, and most ...

  3. A statistically predictive model for future monsoon failure in India

    E-Print Network [OSTI]

    Levermann, Anders

    A statistically predictive model for future monsoon failure in India Jacob Schewe1,2 and Anders Information #12;A statistically predictive model for future monsoon failure in India 2 mm/day numberofyears 0 statistically predictive model for future monsoon failure in India 4 30 o S 15o S 0 o 15o N 30o N A dry May B

  4. Estimating Failure Propagation in Models of Cascading Blackouts

    SciTech Connect (OSTI)

    Dobson, Ian [University of Wisconsin, Madison; Carreras, Benjamin A [ORNL; Lynch, Vickie E [ORNL; Nkei, Bertrand [ORNL; Newman, David E [University of Alaska

    2005-09-01

    We compare and test statistical estimates of failure propagation in data from versions of a probabilistic model of loading-dependent cascading failure and a power systems blackout model of cascading transmission line overloads. The comparisons suggest mechanisms affecting failure propagation and are an initial step towards monitoring failure propagation from practical system data. Approximations to the probabilistic model describe the forms of probability distributions of cascade sizes.

  5. Brittle failure kinetics model for concrete

    SciTech Connect (OSTI)

    Silling, S.A.

    1997-03-01

    A new constitutive model is proposed for the modeling of penetration and large stress waves in concrete. Rate effects are incorporated explicitly into the damage evolution law, hence the term brittle failure kinetics. The damage variable parameterizes a family of Mohr-Coulomb strength curves. The model, which has been implemented in the CTH code, has been shown to reproduce some distinctive phenomena that occur in penetration of concrete targets. Among these are the sharp spike in deceleration of a rigid penetrator immediately after impact. Another is the size scale effect, which leads to a nonlinear scaling of penetration depth with penetrator size. This paper discusses the theory of the model and some results of an extensive validation effort.

  6. A simple approach to modeling ductile failure.

    SciTech Connect (OSTI)

    Wellman, Gerald William

    2012-06-01

    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. Modeling Stochastic Correlated Failures and their Effects on Network Reliability

    E-Print Network [OSTI]

    Hayat, Majeed M.

    in this field have used this concept to generate geographically correlated failures (e.g. [1] and [2]). SomeModeling Stochastic Correlated Failures and their Effects on Network Reliability Mahshid Rahnamay--The physical infrastructure of communication net- works is vulnerable to spatially correlated failures arising

  8. Modeling Space Shuttle Software Failures at Varying Criticality Levels

    E-Print Network [OSTI]

    Morgan, Joseph

    of a software failure data set for an industrial software development project. They propose models based criticality levels. A family of models based on transforms of cumulative time and cumulative failures the exponential, logarithmic, and power models. It also includes models based on transforms of the time per

  9. Modeling shear failure and permeability enhancement due to coupled...

    Office of Scientific and Technical Information (OSTI)

    enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs Citation Details In-Document Search Title: Modeling shear failure and...

  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. Cascade Failure in a Phase Model of Power Grids

    E-Print Network [OSTI]

    Sakaguchi, Hidetsugu

    2012-01-01

    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.

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

    SciTech Connect (OSTI)

    Duffy, Stephen

    2013-09-09

    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.

  13. On modeling damage and failure in ceramic matrix fiber reinforced composites Anthony M. Waas

    E-Print Network [OSTI]

    Mease, Kenneth D.

    On modeling damage and failure in ceramic matrix fiber reinforced composites Anthony M. Waas Seattle, WA 98195-2400 Fiber reinforced ceramic matrix composites (CMC) are targeted for many jet engine of the matrix material. Multiple analytical ply-level models have been developed to predict crack spacing

  14. Failure of materials. (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) |production at a linear(Conference)membranes by(Conference) |Failure

  15. Tacoma Bridge Failure-- a Physical Model

    E-Print Network [OSTI]

    Green, D; Green, Daniel; Unruh, William G.

    2004-01-01

    The cause of the collapse of the Tacoma Narrows Bridge has been a topic of much debate and confusion since the day it fell. Many mischaracterizations of the observed phenomena have limited the widespread understanding of the problem. Nevertheless, there has always been an abundance of evidence in favour of a negative damping model. Negative damping, or positive feedback, is responsible for many large amplitude oscillations observed in many applications. In this paper, we will explain some well-known examples of positive feedback. We will then present a feedback model, derived from fundamental physics, capable of explaining a number of features observed in the instabilities of many bridge decks. This model is supported by computational, experimental and historical data.

  16. Bayesian failure probability model sensitivity study. Final report

    SciTech Connect (OSTI)

    Not Available

    1986-05-30

    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.

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

    SciTech Connect (OSTI)

    Fok, Alex

    2013-10-30

    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.

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

    SciTech Connect (OSTI)

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

    2003-12-19

    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. 1MSE 2090: Introduction to Materials Science Chapter 8, Failure How do Materials Break?

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Outline: Failure Ductile vs. brittle fracture Principles of fracture mechanics Stress concentration Impact Alloys for high-temperature use Not tested: in 8.5 Fracture Toughness 8.14 Data extrapolation methods #12 two fracture modes can be defined - ductile or brittle · Ductile fracture - most metals (not too cold

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

    SciTech Connect (OSTI)

    Bienstock, Daniel

    2014-04-11

    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.

  1. ISSUES ASSOCIATED WITH PROBABILISTIC FAILURE MODELING OF DIGITAL SYSTEMS

    SciTech Connect (OSTI)

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

    2004-09-19

    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.

  2. Gas Flow Tightly Coupled to Elastoplastic Geomechanics for Tight- and Shale-Gas Reservoirs: Material Failure and Enhanced Permeability

    SciTech Connect (OSTI)

    Kim, Jihoon; Moridis, George

    2014-12-01

    We investigate coupled flow and geomechanics in gas production from extremely low permeability reservoirs such as tight and shale gas reservoirs, using dynamic porosity and permeability during numerical simulation. In particular, we take the intrinsic permeability as a step function of the status of material failure, and the permeability is updated every time step. We consider gas reservoirs with the vertical and horizontal primary fractures, employing the single and dynamic double porosity (dual continuum) models. We modify the multiple porosity constitutive relations for modeling the double porous continua for flow and geomechanics. The numerical results indicate that production of gas causes redistribution of the effective stress fields, increasing the effective shear stress and resulting in plasticity. Shear failure occurs not only near the fracture tips but also away from the primary fractures, which indicates generation of secondary fractures. These secondary fractures increase the permeability significantly, and change the flow pattern, which in turn causes a change in distribution of geomechanical variables. From various numerical tests, we find that shear failure is enhanced by a large pressure drop at the production well, high Biot's coefficient, low frictional and dilation angles. Smaller spacing between the horizontal wells also contributes to faster secondary fracturing. When the dynamic double porosity model is used, we observe a faster evolution of the enhanced permeability areas than that obtained from the single porosity model, mainly due to a higher permeability of the fractures in the double porosity model. These complicated physics for stress sensitive reservoirs cannot properly be captured by the uncoupled or flow-only simulation, and thus tightly coupled flow and geomechanical models are highly recommended to accurately describe the reservoir behavior during gas production in tight and shale gas reservoirs and to smartly design production scenarios.

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

    E-Print Network [OSTI]

    Hayat, Majeed M.

    cause failures of power system components such as transmission lines and generators, which, in turn, may1 A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids Mahshid Abstract--Current power grids suffer periodic disturbances that may trigger cascades of component failures

  4. CRITICALITY IN A CASCADING FAILURE BLACKOUT MODEL Dusko P. Nedic

    E-Print Network [OSTI]

    n i f i - cant risk of large blackouts. Keywords: reliability, security, risk, power law 1, for all these types of interac- tion, the risk of cascading failure generally becomes more severe increases? Previous work suggests that a cascading failure does not gradually and uniformly be- come more

  5. Software, the Urn Model, and Failure Peter Bernard Ladkin

    E-Print Network [OSTI]

    Ladkin, Peter B.

    for UK nuclear power plant protection systems using statistical methods [Lit10]. It is the basis for some to perform design function on demand Number of observed demands without failure for a confidence level of 99-History Requirements for On-Demand Functions Acceptable probability of failure to perform design function per hour

  6. Inference based on the em algorithm for the competing risk model with masked causes of failure

    E-Print Network [OSTI]

    Duchesne, Thierry

    Inference based on the em algorithm for the competing risk model with masked causes of failure parameterised competing risks model with masked causes of failure and second-stage data. With a carefully chosen definition of complete data, the maximum likelihood estimation of the cause-specific hazard functions

  7. Tsunami Generation by Submarine Mass Failure. I: Modeling, Experimental Validation, and Sensitivity Analyses

    E-Print Network [OSTI]

    Grilli, Stéphan T.

    Tsunami Generation by Submarine Mass Failure. I: Modeling, Experimental Validation, and Sensitivity with a two-dimensional 2D fully nonlinear potential flow FNPF model for tsunami generation by two idealized types of submarine mass failure SMF : underwater slides and slumps. These simulations feature rigid

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

    SciTech Connect (OSTI)

    L. C. Cadwallader

    2013-01-01

    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.

  9. Failure modes in fiber-reinforced plastic materials. Final report, September 1994

    SciTech Connect (OSTI)

    Weiss, W.; Thomas, C.; Wessels, J.

    1994-09-19

    This report describes the results of a literature review and discussions with industry experts through telephone interviews and attendance at the Natural Gas Vehicle (NGV) Exhibition and the NGV Institute's Second Annual Education Symposium. This quick-response study was precipitated by the fuel tank ruptures which occurred in early 1994 (January 18 and February 1) on two GMC Sierra dedicated natural gas pickup trucks. These vehicles were equipped with Comdyne fully-overwrapped, aluminum-lined, composite fuel cylinders. They were converted to operate on compressed natural gas. The Gas Research Institute (GRI) requested Radian Corporation to conduct the study to address their concerns about NGV composite cylinders. Specifically, GRI was interested in identifying and evaluating available information on field failures in structures of fiberglass materials systems to assist in evaluating the implications of the two NGV fuel tank ruptures.

  10. Selective Recovery From Failures In A Task Parallel Programming Model

    SciTech Connect (OSTI)

    Dinan, James S.; Singri, Arjun; Sadayappan, Ponnuswamy; Krishnamoorthy, Sriram

    2010-05-17

    We present a fault tolerant task pool execution environment that is capable of performing fine-grain selective restart using a lightweight, distributed task completion tracking mechanism. Compared with conventional checkpoint/restart techniques, this system offers a recovery penalty that is proportional to the degree of failure rather than the system size. We evaluate this system using the Self Consistent Field (SCF) kernel which forms an important component in ab initio methods for computational chemistry. Experimental results indicate that fault tolerant task pools are robust in the presence of an arbitrary number of failures and that they offer low overhead in the absence of faults.

  11. Inference for the dependent competing risks model with masked causes of failure

    E-Print Network [OSTI]

    Craiu, V. Radu

    Inference for the dependent competing risks model with masked causes of failure Radu V. Craiu Æ/fail for different reasons. The cause specific hazard rates are taken to be piecewise constant functions. A complication arises when some of the failures are masked within a group of possible causes. Traditionally

  12. 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

    2010-06-01

    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.

  13. Comparing three models of attack and failure tolerance in electric power networks

    E-Print Network [OSTI]

    Hines, P; Blumsack, S

    2010-01-01

    In order to identify the extent to which results from topological graph models are useful for modeling vulnerability in power systems, we measure the susceptibility of power networks to random failures and directed attacks using three measures of vulnerability: characteristic path lengths, connectivity loss and blackout sizes. The first two are purely topological measures, following the procedure described by Albert et al. (2004). The blackout size calculation results from a simplified model of cascading failure in power networks. Tests with randomly selected sections of the Eastern US power grid indicate that in topological dynamics power grids are similar to random graphs, which is to be expected given the observed exponential degree distribution. However the connectivity loss model and the cascading failure model indicate that power grids behave more like scale free networks, in that they are acutely more vulnerable to directed attacks than random failures. These results suggest caution in drawing conclusi...

  14. Modeling Freedom From Progression for Standard-Risk Medulloblastoma: A Mathematical Tumor Control Model With Multiple Modes of Failure

    SciTech Connect (OSTI)

    Brodin, N. Patrik, E-mail: nils.patrik.brodin@rh.dk [Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Vogelius, Ivan R. [Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); Björk-Eriksson, Thomas [Department of Oncology, Skåne University Hospital and Lund University, Lund (Sweden); Munck af Rosenschöld, Per [Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Bentzen, Søren M. [Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen (Denmark); Department of Human Oncology, University of Wisconsin Medical School, Madison, Wisconsin (United States)

    2013-10-01

    Purpose: As pediatric medulloblastoma (MB) is a relatively rare disease, it is important to extract the maximum information from trials and cohort studies. Here, a framework was developed for modeling tumor control with multiple modes of failure and time-to-progression for standard-risk MB, using published pattern of failure data. Methods and Materials: Outcome data for standard-risk MB published after 1990 with pattern of relapse information were used to fit a tumor control dose-response model addressing failures in both the high-dose boost volume and the elective craniospinal volume. Estimates of 5-year event-free survival from 2 large randomized MB trials were used to model the time-to-progression distribution. Uncertainty in freedom from progression (FFP) was estimated by Monte Carlo sampling over the statistical uncertainty in input data. Results: The estimated 5-year FFP (95% confidence intervals [CI]) for craniospinal doses of 15, 18, 24, and 36 Gy while maintaining 54 Gy to the posterior fossa was 77% (95% CI, 70%-81%), 78% (95% CI, 73%-81%), 79% (95% CI, 76%-82%), and 80% (95% CI, 77%-84%) respectively. The uncertainty in FFP was considerably larger for craniospinal doses below 18 Gy, reflecting the lack of data in the lower dose range. Conclusions: Estimates of tumor control and time-to-progression for standard-risk MB provides a data-driven setting for hypothesis generation or power calculations for prospective trials, taking the uncertainties into account. The presented methods can also be applied to incorporate further risk-stratification for example based on molecular biomarkers, when the necessary data become available.

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

    E-Print Network [OSTI]

    Cobanoglu, Mustafa Murat

    2014-03-28

    such as pipeline and operator information, failure causes, consequences of these incidents, cathodic protection conditions, coating conditions, property damage, year of installation information, and etc. However, a number of items are missing. For example... was external corrosion due to inadequate cathodic protection (Riemer and Orazem, 2000). Due to an increasing number of incidents and their consequences, reliability of the pipeline system is becoming crucial for the operators and public in general. Public...

  16. Failure Analysis and Reliability Model Development for Microsystems-Enabled Photovoltaics

    E-Print Network [OSTI]

    Failure Analysis and Reliability Model Development for Microsystems- Enabled Photovoltaics Benjamin, 87185, USA Abstract -- Microsystems-enabled photovoltaics (MEPV) has great potential to meet increasing demands for light-weight, photovoltaic solutions with high power density and efficiency. This paper

  17. Material models of dark energy

    E-Print Network [OSTI]

    Jonathan A. Pearson

    2014-09-16

    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.

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

    SciTech Connect (OSTI)

    Dobson, Ian; Hiskens, Ian; Linderoth, Jeffrey; Wright, Stephen

    2013-12-16

    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

  19. HYPERELASTIC MODELS FOR GRANULAR MATERIALS

    SciTech Connect (OSTI)

    Humrickhouse, Paul W; Corradini, Michael L

    2009-01-29

    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.

  20. Failure Correlation in Software Reliability Models Katerina Goseva Popstojanova and Kishor Trivedi

    E-Print Network [OSTI]

    Goseva-Popstojanova, Katerina

    reliability modeling framework based on Markov renewal processes which nat- urally introduces dependence among for a more flexible and consistent model formulation and solution. The Markov renewal model pre- sentedFailure Correlation in Software Reliability Models Katerina Goseva ­ Popstojanova and Kishor

  1. 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

    2015-01-01

    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.

  2. Iterated Models and Failure Detectors (Brief notes for discussion)

    E-Print Network [OSTI]

    Lynch, Nancy

    power of iterated models at the same rate that it does on non- iterated models. Finally we provide new models. A. Cornejo (CSAIL) TDS Seminar October 11, 2007 2 / 17 #12;Agenda 1 Communication models Atomic models Atomic snapshot Atomic snapshot In a system with n processes, an atomic snapshot object is built

  3. 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

    2009-03-03

    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.

  4. Modeling and Automatic Failure Analysis of Safety-Critical Systems Using Extended Safecharts

    E-Print Network [OSTI]

    Hsiung, Pao-Ann

    techniques, such as fault tree analysis (FTA), failure modes and effects analysis (FMEA), failure modes

  5. Modelling Inter-Industry Material Flows

    E-Print Network [OSTI]

    CIEEDAC Modelling Inter-Industry Material Flows: A review of methodologies For Natural Resources Canada By Maggie Tisdale CIEEDAC Energy and Materials Research Group School of Resource and Environmental .................................................................................................. 2 2.2. INDIRECT EFFECTS

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

    E-Print Network [OSTI]

    There are two fundamental related problems that form the basis .... essentially the approach that is modeled in this paper. However ... would be be equivalent to the thermal ?uctuation in— volved in .... studies of arrays have been carried out [22—

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

    SciTech Connect (OSTI)

    Du, Qiang

    2014-11-12

    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 studyof 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. Injectable Materials for the Treatment of Myocardial Infarction and Heart Failure: The Promise of Decellularized Matrices

    E-Print Network [OSTI]

    Singelyn, Jennifer M.; Christman, Karen L.

    2010-01-01

    milieu that cannot currently be mimicked by other materials, and thus offer promising solutions as injectable therapies

  9. Modeling shear failure and permeability enhancement due to coupled

    Office of Scientific and Technical Information (OSTI)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport)Fermentative Activity onConnect Modeling of ESD

  10. Modeling shear failure and permeability enhancement due to coupled

    Office of Scientific and Technical Information (OSTI)

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport)Fermentative Activity onConnect Modeling of

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

    E-Print Network [OSTI]

    Spencer Jr., Billie F.

    index for the safety assessment of concrete dams and is predicted through dynamic model failure tests INTRODUCTION A great number of high dams will be built in highly seismic areas, the safety evaluation 116024, China ABSTRACT: For the earthquake safety evaluation of dam structures, it is desirable to extend

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

    E-Print Network [OSTI]

    of Wisconsin, Madison WI, 53706, USA Abstract A hidden failure embedded DC model of power transmission systems, the role of the transmission system to provide reliable energy transportation is even more crucial. However, the U.S power transmission grid suffered from more than 400 major blackouts in the past 16 years [1

  13. A Novel Virtual Age Reliability Model for Time-to-Failure Prediction

    E-Print Network [OSTI]

    Cotofana, Sorin

    counts, devices approaching physical feature size limits and nuclear plant comparable power densityA Novel Virtual Age Reliability Model for Time-to-Failure Prediction Yao Wang, Sorin Cotofana their relatively short operating lifetime. To overcome the MTTF weakness, this paper proposes a novel virtual age

  14. Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales

    E-Print Network [OSTI]

    Ben-Zion, Yehuda

    Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales GERT ZO¨ LLER1 of the regions around the fault, static/ kinetic friction laws with possible gradual healing, and stress transfer based on the solution of CHINNERY (1963) for static dislocations in an elastic half-space. As a new

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

    E-Print Network [OSTI]

    Van Mieghem, Piet

    The Impact of the Topology on Cascading Failures in a Power Grid Model Yakup Koça,1 Martijn scale blackouts in power trans- mission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact

  16. Micromechanical Damage Models for Continuous Fiber Reinforced Composite Materials

    E-Print Network [OSTI]

    Wu, Yi

    2013-01-01

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

  17. 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...

  18. Discrete element modelling of cementitious materials 

    E-Print Network [OSTI]

    Brown, Nicholas John

    2013-07-01

    This thesis presents a new bonded particle model that accurately predicts the wideranging behaviour of cementitious materials. There is an increasing use of the Discrete Element Method (DEM) to study the behaviour of ...

  19. Ceramic materials testing and modeling

    SciTech Connect (OSTI)

    Wilfinger, K. R., LLNL

    1998-04-30

    Certain refractory ceramics (notably oxides) have desirable properties suitable for the construction of ceramic waste containers for long term use in nuclear waste disposal applications. In particular, they are far less prone to environmental corrosion than metals under realistic repository conditions. The aqueous corrosion rates of oxides such as magnesium aluminate spinel (MgAl{sub 2}0{sub 4}) and alumina (Al{sub 2}0{sub 4}) fall in the range of a few millimeters per million years. Oxide ceramics are also not likely to be subject to microbiologically influenced corrosion, which apparently can attack most, if not all, of the available engineering metals. Ceramics have a reputation for poor mechanical performance and large, impermeable objects are not easily fabricated by most current fabrication methods. As a result, the most promising approach for incorporating ceramics in large waste packages appears to be to apply a high density ceramic coating to a supporting metallic structure. Ceramic coatings 2048 applied by a thermal spray technique can be made effectively seamless and provide a method for final closure of the waste package while maintaining low average temperatures for the entire assembly. The corrosion resistance of the ceramic should prevent or delay water penetration to the underlying metal, which will in turn provide most of the mechanical strength and toughness required by the application. In this way, the major concerns regarding the ceramic coating become ensuring it is impervious to moisture, its adherence and its resistance to mechanical stresses during handling or resulting from rock fall in the repository. Without water, electrochemical corrosion and microbiologically influenced corrosion processes are considered impossible, so a complete coating should protect the metal vessels for far longer than the current design requirements. Even an imperfect coating should extend the life of the package, delaying the onset and reducing the severity of corrosion by limiting the transport of water and oxygen to the ceramic-metal interface. Thermal spray techniques for ceramic coating metallic structures are currently being explored. The mechanics of thermal spray resembles spray painting in many respects, allowing large surfaces and contours to be covered smoothly. All of the relevant thermal spray processes use a high energy input to melt or partially melt a powdered oxide material, along with a high velocity gas to impinge the molten droplets onto a substrate where they conform, quench, solidify and adhere mechanically. The energy input can be an arc generated plasma, an oxy-fuel flame or an explosion. The appropriate feed material and the resulting coating morphologies vary with technique as well as with application parameters. To date on this project, several versions of arc plasma systems, a detonation coating system and two variations of high velocity oxy-fuel (HVOF) fired processes have been investigated, operating on several different ceramic materials.

  20. Autonomous thruster failure recovery on underactuated spacecraft using model predictive control

    E-Print Network [OSTI]

    Pong, Christopher Masaru

    Thruster failures historically account for a large percentage of failures that have occurred on orbit. These failures are typically handled through redundancy, however, with the push to using smaller, less expensive ...

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

    SciTech Connect (OSTI)

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

    2010-03-01

    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.

  2. 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...

  3. 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))

    1992-05-01

    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.

  4. NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION

    SciTech Connect (OSTI)

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

    2011-11-01

    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. Computational modeling of composite material fires.

    SciTech Connect (OSTI)

    Brown, Alexander L.; Erickson, Kenneth L.; Hubbard, Joshua Allen; Dodd, Amanda B.

    2010-10-01

    Composite materials behave differently from conventional fuel sources and have the potential to smolder and burn for extended time periods. As the amount of composite materials on modern aircraft continues to increase, understanding the response of composites in fire environments becomes increasingly important. An effort is ongoing to enhance the capability to simulate composite material response in fires including the decomposition of the composite and the interaction with a fire. To adequately model composite material in a fire, two physical model development tasks are necessary; first, the decomposition model for the composite material and second, the interaction with a fire. A porous media approach for the decomposition model including a time dependent formulation with the effects of heat, mass, species, and momentum transfer of the porous solid and gas phase is being implemented in an engineering code, ARIA. ARIA is a Sandia National Laboratories multiphysics code including a range of capabilities such as incompressible Navier-Stokes equations, energy transport equations, species transport equations, non-Newtonian fluid rheology, linear elastic solid mechanics, and electro-statics. To simulate the fire, FUEGO, also a Sandia National Laboratories code, is coupled to ARIA. FUEGO represents the turbulent, buoyantly driven incompressible flow, heat transfer, mass transfer, and combustion. FUEGO and ARIA are uniquely able to solve this problem because they were designed using a common architecture (SIERRA) that enhances multiphysics coupling and both codes are capable of massively parallel calculations, enhancing performance. The decomposition reaction model is developed from small scale experimental data including thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) in both nitrogen and air for a range of heating rates and from available data in the literature. The response of the composite material subject to a radiant heat flux boundary condition is examined to study the propagation of decomposition fronts of the epoxy and carbon fiber and their dependence on the ambient conditions such as oxygen concentration, surface flow velocity, and radiant heat flux. In addition to the computational effort, small scaled experimental efforts to attain adequate data used to validate model predictions is ongoing. The goal of this paper is to demonstrate the progress of the capability for a typical composite material and emphasize the path forward.

  6. Viscoelastic models for explosive binder materials

    SciTech Connect (OSTI)

    Bardenhagen, S.G.; Harstad, E.N.; Maudlin, P.J.; Gray, G.T. [Los Alamos National Lab., NM (United States); Foster, J.C. Jr. [Wright Lab., Eglin AFB, FL (United States)

    1997-07-01

    An improved model of the mechanical properties of the explosive contained in conventional munitions is needed to accurately simulate performance and accident scenarios in weapons storage facilities. A specific class of explosives can he idealized as a mixture of two components: energetic crystals randomly suspended in a polymeric matrix (binder). Strength characteristics of each component material are important in the macroscopic behavior of the composite (explosive). Of interest here is the determination of an appropriate constitutive law for a polyurethane binder material. This paper is a continuation of previous work in modeling polyurethane at moderately high strain rates and for large deformations. Simulation of a large deformation (strains in excess of 100%) Taylor Anvil experiment revealed numerical difficulties which have been addressed. Additional experimental data have been obtained including improved resolution Taylor Anvil data, and stress relaxation data at various strain rates. A thorough evaluation of the candidate viscoelastic constitutive model is made and possible improvements discussed.

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

    E-Print Network [OSTI]

    Shin, Jun Seob

    2009-01-01

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

  8. Hawaii International Conference on System Sciences, January 2003, Hawaii. c 2003 IEEE. A probabilistic loading-dependent model of cascading failure

    E-Print Network [OSTI]

    Newman, David

    blackouts of electric power systems are typi- cally caused by cascading failure of heavily loaded system, loading-dependent cascading failure occurs in large blackouts of electric power transmission systems components. We introduce the CASCADE model of cascad- ing failure of a system with many identical components

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

    E-Print Network [OSTI]

    Scala, Antonio

    2015-01-01

    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".

  10. Fire and materials modeling for transportation systems

    SciTech Connect (OSTI)

    Skocypec, R.D.; Gritzo, L.A.; Moya, J.L.; Nicolette, V.F.; Tieszen, S.R.; Thomas, R.

    1994-10-01

    Fire is an important threat to the safety of transportation systems. Therefore, understanding the effects of fire (and its interaction with materials) on transportation systems is crucial to quantifying and mitigating the impact of fire on the safety of those systems. Research and development directed toward improving the fire safety of transportation systems must address a broad range of phenomena and technologies, including: crash dynamics, fuel dispersion, fire environment characterization, material characterization, and system/cargo thermal response modeling. In addition, if the goal of the work is an assessment and/or reduction of risk due to fires, probabilistic risk assessment technology is also required. The research currently underway at Sandia National Laboratories in each of these areas is summarized in this paper.

  11. Engineering, Modeling and Testing of Composite Absorbing Materials for

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    13 Engineering, Modeling and Testing of Composite Absorbing Materials for EMC Applications Marina al., 2008). Application of absorbing materials for the design of shielding enclosures, coatings to electronic products, the engineered absorbing materials would allow for compliance with requirements

  12. A statistically predictive model for future monsoon failure in India This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Levermann, Anders

    A statistically predictive model for future monsoon failure in India This article has been) 044023 (9pp) doi:10.1088/1748-9326/7/4/044023 A statistically predictive model for future monsoon failure in India Jacob Schewe and Anders Levermann Potsdam Institute for Climate Impact Research, Telegrafenberg A

  13. JOURNAL OF MATERIALS SCIENCE 36 (2001) 2851 2863 A crystal plasticity materials constitutive model

    E-Print Network [OSTI]

    Grujicic, Mica

    2001-01-01

    JOURNAL OF MATERIALS SCIENCE 36 (2001) 2851­ 2863 A crystal plasticity materials constitutive model using a three-dimensional, isothermal, rate-dependent, large-strain, crystal-plasticity based materials in the crystal-plasticity materials constitutive relations are assessed using the available experimental

  14. Exploring the interdependencies between parameters in a material model.

    SciTech Connect (OSTI)

    Silling, Stewart Andrew; Fermen-Coker, Muge

    2014-01-01

    A method is investigated to reduce the number of numerical parameters in a material model for a solid. The basis of the method is to detect interdependencies between parameters within a class of materials of interest. The method is demonstrated for a set of material property data for iron and steel using the Johnson-Cook plasticity model.

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

    E-Print Network [OSTI]

    Rahman, Sharif

    Stochastic multiscale models for fracture analysis of functionally graded materials Arindam three multiscale models, including sequential, invasive, and concurrent models, for fracture analysis methods for fracture reliability analysis. The par- ticle volume fractions, defined by a generic

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

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

    - Scale-Bridging Simulations Active Materials in Li-ion Batteries, and Validation in BATT Electrodes Modeling - Scale-Bridging Simulations Active Materials in Li-ion Batteries, and...

  17. 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...

  18. 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...

  19. Combining Genetic Algorithms & Simulation to Search for Failure Scenarios in System Models

    E-Print Network [OSTI]

    Mills, Chris Dabrowski, Jim Filliben and Sandy Ressler NIST Cloud Security Working Group July 17, 2013 for Failure Scenarios ­ Evaluating Method · Conclusions & Future Work July 17, 2013 NIST Cloud Security WG 2 #12;July 17, 2013 NIST Cloud Security WG 3 GROWING GLOBAL DEPENDENCE ON COMPLEX INFO. SYSTEMS #12;July

  20. 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

  1. A Domain Wall Model for Hysteresis in Piezoelectric Materials

    E-Print Network [OSTI]

    A Domain Wall Model for Hysteresis in Piezoelectric Materials Ralph C. Smith Center for Research to attain the full potential of the materials as sensors and actuators in high performance applications design. i #12; 1 Introduction Piezoelectric materials provide the capability for designing actuators

  2. 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 ...

  3. Failure of Functionally Graded Materials G.H. PAULINO,Z.-H. JIN, and R.H. DODDS,Jr.

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    .13.5.1 Metal/Ceramic FGM Fracture Specimen 638 2.13.5.2 Precracking of Metal/Ceramic FGMs 639 2 of reinforcement and matrix (base) materials in a continuous manner as illustrated by Figure 1. This new concept by providing a compositional distribution function, C(x), consistent with these condi- tions. For instance

  4. Geometric control of failure behavior in perforated sheets

    E-Print Network [OSTI]

    Michelle M. Driscoll

    2014-11-20

    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.

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

    SciTech Connect (OSTI)

    Schembri, Philip E.; Lewis, Matthew W.

    2014-02-27

    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.

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

    SciTech Connect (OSTI)

    Dunn, Martin L.; Talmage, Mellisa J.; 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

    2006-10-01

    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.

  7. 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

    1984-01-01

    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 ...

  8. 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.

    2012-02-14

    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.

  9. 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

    2012-04-23

    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.

  10. IOP PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 15 (2007) S377S392 doi:10.1088/0965-0393/15/4/S05

    E-Print Network [OSTI]

    Ghosh, Somnath

    2007-01-01

    in their microstructure often affects their failure properties like fracture toughness and ductility in an adverse manner of ductile fracture in particle reinforced metallic materials Chao Hu, Jie Bai and Somnath Ghosh Department modules contributing to the overall framework of multi-scale modelling of ductile fracture of particle

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

    E-Print Network [OSTI]

    Shahri, Mehdi Abbaszadeh

    2006-04-12

    Stability????.?????? 25 5.2 Wellbore Stability in Shale???..??????????.. 26 5.3 Various Instability Risk Criteria?.???????.???. 27 5.4 Borehole Stability Analysis?????????????.. 27 CHAPTER VI..., to the manifold methods of mining ore and aggregate materials, to the stability of petroleum wellbores, and including newer applications such as geothermal energy and radioactive waste disposal. 1.1 Importance of Primary Cementing on Cost Avoiding remedial...

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

    SciTech Connect (OSTI)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J.

    1995-07-01

    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. 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

  14. Heart Failure Cardiovascular Features of Heart Failure

    E-Print Network [OSTI]

    Morrell, Christopher H.

    Heart Failure Cardiovascular Features of Heart Failure With Preserved Ejection Fraction Versus of patients with heart failure with preserved ejection fraction (HFpEF) that differ from those in individuals failure. Background Heart failure with preserved ejection fraction often develops in HLVH patients

  15. Modeling rf breakdown arcs II: plasma / materials interactions

    E-Print Network [OSTI]

    Insepov, Zeke; Proslier, Thomas; Mahalingam, Sudhakar; Veitzer, S

    2010-01-01

    Continuing the description of rf vacuum arcs from an earlier paper, we describe some aspects of the interaction of vacuum arcs that involve the surface. This paper describes aspects of plasma materials interactions that affect the arc and models measurement of the surface field using the Tonks-Frenkel and the spinodal electrohydrodynamic instabilities, a realistic model for the generation and evaluation of high field enhancements, unipolar arcs, creep and other effects.

  16. Deformation during casting of steel: model and material C. Beckermann

    E-Print Network [OSTI]

    Beckermann, Christoph

    Deformation during casting of steel: model and material properties C. Monroe C. Beckermann Dimensional differences between a final casting and its design are casting distortions. Distortion is created by the deformation occurring throughout solidification and further cooling during the casting process. Accurate

  17. Concurrent multiscale computational modeling for dense dry granular materials interfacing

    E-Print Network [OSTI]

    Regueiro, Richard A.

    of interfacial mechanics between granular soil and tire, tool, or penetrometer, while properly representing far computational modeling of interfacial mechanics between granular materials and deformable solid bodies, agricultural grains (in silo flows), dry soils (sand, silt, gravel), and lunar and martian regolith (soil found

  18. Modeling of material response during fiber drawing of semicrystalline pet 

    E-Print Network [OSTI]

    Yadav, Seemant

    2007-09-17

    'Neal May 2006 Major Subject: Mechanical Engineering iii ABSTRACT Modeling of Material Response during Fiber Drawing of Semicrystalline PET. (May 2006) Seemant Yadav, B.E., Shri Govindram Seksaria Institute of Technology and Science, Indore... Seksaria Institute of Technology and Science, Indore, India. Bachelor of Engineering, Mechanical Engineering ...

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

    E-Print Network [OSTI]

    Darabi Konartakhteh, Masoud

    2012-10-19

    for bituminous materials and asphalt mixes. The developed thermodynamic-based framework is general and can be applied for constitutive modeling of different materials such as bituminous materials, soft materials, polymers, and biomaterials. This framework...

  20. Thermal Cycling on Fatigue Failure of the Plutonium Vitrification Melter

    SciTech Connect (OSTI)

    Jordan, Jeffrey; Gorczyca, Jennifer

    2009-02-11

    One method for disposition of excess plutonium is vitrification into cylindrical wasteforms. Due to the hazards of working with plutonium, the vitrification process must be carried out remotely in a shielded environment. Thus, the equipment must be easily maintained. With their simple design, induction melters satisfy this criterion, making them ideal candidates for plutonium vitrification. However, due to repeated heating and cooling cycles and differences in coefficients of thermal expansion of contacting materials fatigue failure of the induction melter is of concern. Due to the cost of the melter, the number of cycles to failure is critical. This paper presents a method for determining the cycles to failure for an induction melter by using the results from thermal and structural analyses as input to a fatigue failure model.

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

    SciTech Connect (OSTI)

    Germann, Timothy C.

    2014-07-08

    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.

  2. A 4D geometrical modeling of a material aging

    E-Print Network [OSTI]

    A. Chudnovsky; S. Preston

    2006-04-16

    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.

  3. 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

    2014-06-01

    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.

  4. Material model calibration through indentation test and stochastic inverse analysis

    E-Print Network [OSTI]

    Buljak, Vladimir

    2015-01-01

    Indentation test is used with growing popularity for the characterization of various materials on different scales. Developed methods are combining the test with computer simulation and inverse analyses to assess material parameters entering into constitutive models. The outputs of such procedures are expressed as evaluation of sought parameters in deterministic sense, while for engineering practice it is desirable to assess also the uncertainty which affects the final estimates resulting from various sources of errors within the identification procedure. In this paper an experimental-numerical method is presented centered on inverse analysis build upon data collected from the indentation test in the form of force-penetration relationship (so-called indentation curve). Recursive simulations are made computationally economical by an a priori model reduction procedure. Resulting inverse problem is solved in a stochastic context using Monte Carlo simulations and non-sequential Extended Kalman filter. Obtained re...

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

    SciTech Connect (OSTI)

    Shen, Chen

    2014-01-20

    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.

  6. Constitutive Model for Material Comminuting at High Shear Rate

    E-Print Network [OSTI]

    Zdenek P. Bazant; Ferhun C. Caner

    2013-06-04

    The modeling of high velocity impact into brittle or quasibrittle solids is hampered by the unavailability of a constitutive model capturing the effects of material comminution into very fine particles. The present objective is to develop such a model, usable in finite element programs. The comminution at very high strain rates can dissipate a large portion of the kinetic energy of an impacting missile. The spatial derivative of the energy dissipated by comminution gives a force resisting the penetration, which is superposed on the nodal forces obtained from the static constitutive model in a finite element program. The present theory is inspired partly by Grady's model for comminution due to explosion inside a hollow sphere, and partly by analogy with turbulence. In high velocity turbulent flow, the energy dissipation rate is enhanced by the formation of micro-vortices (eddies) which dissipate energy by viscous shear stress. Similarly, here it is assumed that the energy dissipation at fast deformation of a confined solid gets enhanced by the release of kinetic energy of the motion associated with a high-rate shear strain of forming particles. For simplicity, the shape of these particles in the plane of maximum shear rate is considered to be regular hexagons. The rate of release of free energy density consisting of the sum of this energy and the fracture energy of the interface between the forming particle is minimized. The particle sizes are assumed to be distributed according to Schuhmann's power law. It is concluded that the minimum particle size is inversely proportional to the (2/3)-power of the shear strain rate, that the kinetic energy release is to proportional to the (2/3)-power, and that the dynamic comminution creates an apparent material viscosity inversely proportional to the (1/3)-power of the shear strain rate.

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

    SciTech Connect (OSTI)

    Sabau, Adrian S [ORNL

    2015-01-01

    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.

  8. MARS OBSERVER Mission Failure

    E-Print Network [OSTI]

    Rhoads, James

    of Mars Observer Mission Failure.. ................... D-12 a. Most Probable Cause: Leakage of NT0 Through Check Valves .................................................................. D-14 b. Potential Cause: Pressure Regulator Failure....................... D-28 c. Potential Cause: Failure of a Pyro Valve Charge

  9. Fracture Mechanics and Failure Analysis

    E-Print Network [OSTI]

    New South Wales, University of

    concepts: Griffith criterion, K=Ya, K=KIC, ductile and brittle fracture, cyclic fatigue, environmentally, yield criteria. 4 Elastic-Plastic Analysis 5 Fracture toughness testing 6 Crack Growth Resistance - RMATS4004 Fracture Mechanics and Failure Analysis Course Outline Session 1, 2015 School of Materials

  10. A review of macroscopic ductile failure criteria.

    SciTech Connect (OSTI)

    Corona, Edmundo; Reedlunn, Benjamin

    2013-09-01

    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.

  11. 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

  12. 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

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

    E-Print Network [OSTI]

    Minnich, Austin (Austin Jerome)

    2008-01-01

    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, ...

  14. Modeling and simulation of material removal with particulate flows

    E-Print Network [OSTI]

    Arbelaez, D; Zohdi, T I; Dornfeld, David

    2008-01-01

    optimization In material removal processes there are a large number of input parameters which control the quality of the process.

  15. The recent times have seen a surge in computational modeling of materials and processes. New research initiatives like the Materials Genome Initiative (MGI)

    E-Print Network [OSTI]

    Ghosh, Somnath

    . New research initiatives like the Materials Genome Initiative (MGI) and the Integrated Computational Materials Science & Engineering (ICMSE) are creating unprecedented opportunities for unraveling new1 PREFACE The recent times have seen a surge in computational modeling of materials and processes

  16. A Model for Asymmetric Hysteresis in Piezoceramic Materials

    E-Print Network [OSTI]

    by piezoelectric materials at moderate to high field levels. For soft materials in which dipoles are easily property of piezoelectric materials is the presence of hysteresis and constitutive non­ linearities at moderate to high drive levels. In certain applications, the degree of hysteresis can be minimized

  17. Modelling Heat Transport Across Nano-scale Material Interfaces for Next-generation Electronic Devices

    E-Print Network [OSTI]

    Milgram, Paul

    ) thermal boundary resistance between two dissimilar semiconductor materials using a combinationModelling Heat Transport Across Nano-scale Material Interfaces for Next-generation Electronic) with customized thermal transport properties. The scattering of thermal energy carriers at fabricated interfaces

  18. Export Failure and its Consequences: Theory and Evidence

    E-Print Network [OSTI]

    Mora, Jesse

    2015-01-01

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

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

    DOE Patents [OSTI]

    Hoffman, Edward L. (Alameda, CA)

    2009-03-03

    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.

  20. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion toMSDS onBudgetMaterialMaterials Materials Access to

  1. New Computer Model Pinpoints Prime Materials for Carbon Capture

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

    Lab's Materials Science Division; and Michael W. Deem of the Departments of Bioengineering and Physics and Astronomy at Rice University. This work has been supported by the...

  2. Failure modes in surface micromachined microelectromechanical actuators

    SciTech Connect (OSTI)

    Miller, S.L.; Rodgers, M.S.; LaVigne, G.; Sniegowski, J.J.; Clews, P.; Tanner, D.M.; Peterson, K.A.

    1998-03-01

    In order for the rapidly emerging field of MicroElectroMechanical Systems (MEMS) to meet its extraordinary expectations regarding commercial impact, issues pertaining to how they fail must be understood. The authors identify failure modes common to a broad range of MEMS actuators, including adhesion (stiction) and friction induced failures caused by improper operational methods, mechanical instabilities, and electrical instabilities. Demonstrated methods to mitigate these failure modes include implementing optimized designs, model based operational methods, and chemical surface treatments.

  3. 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

  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. Computational Modeling of Heterogeneous Reactive Materials at the Mesoscale

    SciTech Connect (OSTI)

    BAER, MARVIN R.

    1999-09-22

    The mesoscopic processes of consolidation, deformation and reaction of shocked porous energetic materials are studied using shock physics analysis of impact on a collection of discrete ''crystals.'' Highly resolved three-dimensional CTH simulations indicate that rapid deformation occurs at material contact points causing large amplitude fluctuations of stress states with wavelengths of the order of several particle diameters. Localization of energy produces ''hot-spots'' due to shock focusing and plastic work near internal boundaries as material flows into interstitial regions. Numerical experiments indicate that ''hot-spots'' are strongly influenced by multiple crystal interactions. Chemical reaction processes also produce multiple wave structures associated with particle distribution effects. This study provides new insights into the micromechanical behavior of heterogeneous energetic materials strongly suggesting that initiation and sustained reaction of shocked heterogeneous materials involves states distinctly different from single jump state descriptions.

  6. IEEE TRANSACTIONS ON RELIABILITY, VOL. 49, NO. 1, MARCH 2000 37 Failure Correlation in Software Reliability Models

    E-Print Network [OSTI]

    Goseva-Popstojanova, Katerina

    property of the developed Markov renewal modeling approach is its flexibility. It allows con- struction the analysis either on Markov chain theory or on renewal process theory. Thus, our modeling approach Reliability Models Katerina Goseva-Popstojanova, Member, IEEE, and Kishor S. Trivedi, Fellow, IEEE Abstract

  7. Ballistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel: A Computational

    E-Print Network [OSTI]

    Grujicic, Mica

    -welding of a prototypical high-hardness armor-grade martensitic steel, MIL A46100. The model predictions concerning-tempered, high-hardness, low-alloy martensitic, ar- mor-grade steel). A summary of Johnson-Cook material- modelBallistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel

  8. Micromechanical Modeling of Multiphysical Behavior of Smart Materials Using the Variational

    E-Print Network [OSTI]

    Yu, Wenbin

    materials might exhibit new properties not existing in any of the constituents due to the couplingMicromechanical Modeling of Multiphysical Behavior of Smart Materials Using the Variational to predict the effective properties as well as the local fields of periodic smart materials responsive

  9. Assessing Models of Public Understanding In ELSI Outreach Materials

    SciTech Connect (OSTI)

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

    2006-03-01

    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.

  10. 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, ...

  11. Multiscale modeling and analysis of nanofibers and nonwoven materials

    E-Print Network [OSTI]

    Buell, Sezen

    2010-01-01

    Nanostructured fibrous materials have been made more readily available in large part owing to recent advances in electrospinning, which is a technique for the production of nanofibers with diameters down to the range of a ...

  12. First-principles modeling of materials for nuclear energy applications

    SciTech Connect (OSTI)

    Dmitriev, Andrey I. Nikonov, Anton Yu.; Ponomareva, Alena V.; Abrikosov, Igor A.; Barannikova, Svetlana A.

    2014-11-14

    We discuss recent developments in the field of ab initio electronic structure theory and its use for studies of materials for nuclear energy applications. We review state-of-the-art simulation methods that allow for an efficient treatment of effects due to chemical and magnetic disorder, and illustrate their predictive power with examples of two materials systems, Fe-Cr-Ni alloys and Zr-Nb alloys.

  13. Modeling decadal bed material sediment flux based on stochastic Michael Bliss Singer and Thomas Dunne

    E-Print Network [OSTI]

    Singer, Michael

    Modeling decadal bed material sediment flux based on stochastic hydrology Michael Bliss Singer; published 18 March 2004. [1] Estimates of decadal bed material sediment flux and net storage are derived by driving sediment transport calculations with a stochastic hydrology model. The resulting estimates

  14. A model for aging under deformation field, residual stresses and strains in soft glassy materials

    E-Print Network [OSTI]

    Joshi, Yogesh Moreshwar

    A model for aging under deformation field, residual stresses and strains in soft glassy materials Yogesh M. Joshi* A model is proposed that considers aging and rejuvenation in a soft glassy material as, respectively, a decrease and an increase in free energy. The aging term is weighted by an inverse

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

    E-Print Network [OSTI]

    Deng, Xunming

    solar cells and/or the comparison of these predicted results with real multi-junction devices have beenMODELING OF TRIPLE JUNCTION A-SI SOLAR CELLS USING ASA: ANALYSIS OF DEVICE PERFORMANCE UNDER, University of Toledo, Toledo, OH 43606 ABSTRACT Triple junction a-Si solar cells have been modeled

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion toMSDS onBudgetMaterial

  17. A Free Energy Model for Hysteresis in Ferroelectric Materials

    E-Print Network [OSTI]

    to the successful use of piezoelectric transducers in applications ranging from hybrid motor design The capability of piezoelectric materials to both actuate and sense derives from the noncentrosym- metric nature stresses also alter the ionic configuration which gener- ates the voltages measured in piezoelectric

  18. A Free Energy Model for Hysteresis in Ferroelectric Materials

    E-Print Network [OSTI]

    to the successful use of piezoelectric transducers in applications ranging from hybrid motor design to struct The capability of piezoelectric materials to both actuate and sense derives from the noncentrosym­ metric nature stresses also alter the ionic configuration which gener­ ates the voltages measured in piezoelectric

  19. Surface Finish Modeling in Micromilling of Biocompatible Materials 

    E-Print Network [OSTI]

    Berestovskyi, Dmytro V

    2013-06-05

    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...

  20. 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)

    2011-06-23

    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.

  1. 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

  2. COMPUTER MODELING OF NUCLIDE ADSORPTION ON GEOLOGIC MATERIALS

    E-Print Network [OSTI]

    Silva, R.J.

    2010-01-01

    11899 G COMPUTER MODELING OF NUCLIDE ADSORPTION ON GEOLOGICdefined as the amount of nuclide adsorbed per gram of claydivided by the amount of nuclide per milliliter of solution,

  3. Measurement and modeling of hyperfine parameters in ferroic materials

    E-Print Network [OSTI]

    Gonçalves, João Nuno; Correia, J G

    This thesis presents the results of perturbed angular correlation (PAC) experiments , an experimental technique which measures the hyperfine interaction at probes (radioactive ions implanted in the materials to study), from which one infers local information on an atomic scale. Furthermore, abinitio calculations using density functional theory electronic obtain results that directly complement the experiments, and are also used for theoretical research. These methods were applied in two families of materials. The manganites, with the possible existence of magnetic, charge, orbital and ferroelectric orders, are of fundamental and technological interest. The experimental results are obtained in the alkaline-earth manganites (Ca, Ba, Sr), with special interest due to the structural variety of possible polymorphs. With probes of Cd and In the stability of the probe and its location in a wide temperature range is established and a comparison with calculations allows the physical interpretation of the results. Cal...

  4. Variable horizon model predictive control: robustness and optimality

    E-Print Network [OSTI]

    Shekhar, Rohan Chandra

    2012-07-03

    . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 6.3 Kinematic vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 6.4 Mechanism model showing generalised coordinates . . . . . . . . . . . . . . . . 109 6.5 Static balance of material failure forces... .1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 6.1.1 Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 6.2 Mechanism Model...

  5. SYNTHETIC SLING FAILURE - EVALUATIONS & RECOMMENDATIONS

    SciTech Connect (OSTI)

    MACKEY TC; HENDERSON CS

    2009-10-26

    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.

  6. Criticality in the approach to failure in amorphous solids

    E-Print Network [OSTI]

    Jie Lin; Thomas Gueudré; Alberto Rosso; Matthieu Wyart

    2015-07-28

    Failure of amorphous solids is fundamental to various phenomena, including landslides and earthquakes. Recent experiments indicate that highly plastic regions form elongated structures that are especially apparent near the maximal shear stress $\\Sigma_{\\max}$ where failure occurs. This observation suggested that $\\Sigma_{\\max}$ acts as a critical point where the length scale of those structures diverges, possibly causing macroscopic transient shear bands. Here we argue instead that the entire solid phase ($\\Sigmaplasticity always involves system-spanning events, and that their magnitude diverges at $\\Sigma_{\\max}$ independently of the presence of shear bands. We relate the statistics and fractal properties of these rearrangements to an exponent $\\theta$ that captures the stability of the material, which is observed to vary continuously with stress, and we confirm our predictions in elastoplastic models.

  7. 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...

  8. Micromechanical Damage Models for Continuous Fiber Reinforced Composite Materials

    E-Print Network [OSTI]

    Wu, Yi

    2013-01-01

    fatigue crack propagation of penny-shaped cracks, Journal ofG. and Li, S.F. (2004). A penny-shaped cohesive crack modelmicrocracks. A cohesive penny-shape microcrack model is

  9. 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

    that aims to predict the future failure of rod pump units. Innovative and modern, this novel technology provides a new approach to the maintenance of rod pumps through a system that increases efficiency while technology to predict the future failure of rod pumps. The predictions are based on the past experiences

  10. Modeling and Identification of Material Parameters in Coupled Torsion and Bending

    E-Print Network [OSTI]

    coupled torsion and bending. In this paper we present a model (Section 2) for coupled torsion and bending and damping (bending and torsional) in vibration experiments. The model presented in this paper is itself new3 y 3 y Modeling and Identification of Material Parameters in Coupled Torsion and Bending H

  11. Failure mechanisms in MEMS.

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen

    2003-07-01

    MEMS components by their very nature have different and unique failure mechanisms than their macroscopic counterparts. This paper discusses failure mechanisms observed in various MEMS components and technologies. MEMS devices fabricated using bulk and surface micromachining process technologies are emphasized. MEMS devices offer uniqueness in their application, fabrication, and functionality. Their uniqueness creates various failure mechanisms not typically found in their bulk or IC counterparts. In ICs, electrical precautions are taken to mitigate failure. In MEMS, both electrical and mechanical precautions must be enacted to reduce the risk of failure and increased reliability. Unlike ICs, many MEMS components are designed to interact with their environment, making the fabrication, testing, and packaging processes critical for the success of the device.

  12. An improved constitutive model for cyclic material behavior in creep range

    SciTech Connect (OSTI)

    Kussmaul, K.; Maile, K.; Xu, H.; Sheng, S.

    1995-12-31

    Structural components operated at elevated temperatures are often subjected to complex loading histories combining cyclic plasticity and creep. The design and life prediction of these components require accurate description of the non-linear stress-strain response under the cyclic loading. In the paper the results of an ongoing R&D-programme performed at MPA Stuttgart is presented. The objective of this work is to model the cyclic material behavior in the temperature range where time-dependent plasticity is dominant. A series of tests from room temperature UP to 550{degrees}C have been carried out to determine the cyclic material behavior of the turbine steels 1 CrMoV, 2CrMoVNiW and the bolt material Nimonic 80A. On the basis of the acquired experimental data the commonly used constitutive model developed by Chaboche et al. is evaluated and improved. The following aspects are considered in the improved model: Influence of the kinematic back stress on the viscoplastic material behavior Description of the temperature dependent and time-dependent viscosity Method of determination of the material constants used in the model: The comparison of these analytical results and the experimental data shows that the improved model is suitable to describe the cyclic material behavior under uniaxial loading. To verify the developed model for multiaxial loading on the basis of the test data, an implementation of the constitutive model in a finite element code will be performed.

  13. Identifying Affinity Classes of Inorganic Materials Binding Sequences via a Graph-based Model

    E-Print Network [OSTI]

    Buffalo, State University of New York

    material. We first generate a large set of simulated peptide sequences based on an amino acid transition peptide sequences, which are usually 7-14 amino acids long, are differentiated from other polypeptides1 Identifying Affinity Classes of Inorganic Materials Binding Sequences via a Graph-based Model Nan

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

    E-Print Network [OSTI]

    Meier, Joseph D. (Joseph David)

    2013-01-01

    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. 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...

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

    E-Print Network [OSTI]

    ENERGY Hydrogen Pipeline Material Testing Facility Objective We provide critical data, measurement methods and models that enable safe and economical transport, delivery and storage of hydrogen fuel predictions about the safe operating limits of pipelines carrying pressurized gaseous hydrogen, thereby

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

    E-Print Network [OSTI]

    Watson, Aaron Michael

    2002-01-01

    There has been some concern in recent years about the buildup of separated civil plutonium in the world. In order to address issues related to these concerns, it is useful to have models that provide quantitative predictions of this buildup, under...

  18. Thermomechanics of damageable materials under diffusion:modeling and analysis

    E-Print Network [OSTI]

    Tomas Roubicek; Giuseppe Tomassetti

    2014-12-16

    We propose a thermodynamically consistent general-purpose model describing diffusion of a solute or a fluid in a solid undergoing possible phase transformations and damage, beside possible visco-inelastic processes. Also heat generation/consumption/transfer is considered. Damage is modelled as rate-independent. The applications include metal-hydrogen systems with metal/hydride phase transformation, poroelastic rocks, structural and ferro/para-magnetic phase transformation, water and heat transport in concrete, and, if diffusion is neglected, plasticity with damage and viscoelasticity, etc. For the ensuing system of partial differential equations and inclusions, we prove existence of solutions by a carefully devised semi-implicit approximation scheme of the fractional-step type.

  19. Modeling Magnetism in Rare-Earth Intermetallic Materials | The Ames

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGEMission Mission MissionofLaboratory Modeling Magnetism

  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

    bainitic or martensitic microstructures in the normalised condition. After normalising the steels and Microstructure Modelling, H. K. D. H. Bhadeshia Lecture 14: Creep­Resistant Steel, Case Study Introduction Typical operating parameters for steels used in the manufacture of power plant are compared against

  1. 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

  2. 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

  3. On models for viscoelastic fluid-like materials that are mechanically incompressible and

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    On models for viscoelastic fluid-like materials that are mechanically incompressible and thermally of the full Navier­Stokes­Fourier system. J. Math. Fluid Mech., 11:274­302, 2009 Mechanically incompressible;Viscoelastic fluids ­ Maxwell model F l lsld µm m Mechanical analogue: Spring ­ energy storage. Dashpot

  4. Filament-Level Modeling of Aramid-Based High-Performance Structural Materials

    E-Print Network [OSTI]

    Grujicic, Mica

    Filament-Level Modeling of Aramid-Based High-Performance Structural Materials M. Grujicic, W/ filaments. These fibers can be considered as prototypes for advanced high strength/high-stiffness fibers to be most affected by the presence of sheet stacking faults. Keywords filament-level modeling, Kevlar

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

    E-Print Network [OSTI]

    developed high-energy-density batteries, e.g., the nickel-metal hydride battery and the lithium-ion batteryModeling 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

  6. 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)

    2009-12-15

    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.

  7. NO. IRIEV. NC LSG Single Point Failure

    E-Print Network [OSTI]

    Rathbun, Julie A.

    of high reliability component parts and accepted materials, and by the use of highly reliability design scientific data will be lost (tidal, lunar free oscillation, lunar seismic activity, and the drift 4 DATE 5/18/71 7. Seismic Amplifier and Filter - Failure will result in inability to accept

  8. An Experimental Study of Shear-Dominated Failure in the 2013 Sandia Fracture Challenge Specimen

    SciTech Connect (OSTI)

    Corona, Edmundo; Deibler, Lisa Anne; Reedlunn, Benjamin; Ingraham, Mathew Duffy; Williams, Shelley

    2015-04-01

    This report presents an experimental study motivated by results obtained during the 2013 Sandia Fracture Challenge. The challenge involved A286 steel, shear-dominated compression specimens whose load-deflection response contained a load maximum fol- lowed by significant displacement under decreasing load, ending with a catastrophic fracture. Blind numerical simulations deviated from the experiments well before the maximum load and did not predict the failure displacement. A series of new tests were conducted on specimens machined from the original A286 steel stock to learn more about the deformation and failure processes in the specimen and potentially improve future numerical simulations. The study consisted of several uniaxial tension tests to explore anisotropy in the material, and a set of new tests on the compression speci- men. In some compression specimen tests, stereo digital image correlation (DIC) was used to measure the surface strain fields local to the region of interest. In others, the compression specimen was loaded to a given displacement prior to failure, unloaded, sectioned, and imaged under the microscope to determine when material damage first appeared and how it spread. The experiments brought the following observations to light. The tensile tests revealed that the plastic response of the material is anisotropic. DIC during the shear- dominated compression tests showed that all three in-plane surface strain components had maxima in the order of 50% at the maximum load. Sectioning of the specimens revealed no signs of material damage at the point where simulations deviated from the experiments. Cracks and other damage did start to form approximately when the max- imum load was reached, and they grew as the load decreased, eventually culminating in catastrophic failure of the specimens. In addition to the steel specimens, a similar study was carried out for aluminum 7075-T651 specimens. These specimens achieved much lower loads and displacements, and failure occurred very close to the maximum in the load-deflection response. No material damage was observed in these specimens, even when failure was imminent. In the future, we plan to use these experimental results to improve numerical simu- lations of the A286 steel experiments, and to improve plasticity and failure models for the Al 7075 stock. The ultimate goal of our efforts is to increase our confidence in the results of numerical simulations of elastic-plastic structural behavior and failure.

  9. Predicting age of ovarian failure after radiation to a field that includes the ovaries

    SciTech Connect (OSTI)

    Wallace, W. Hamish B. . E-mail: Hamish.Wallace@ed.ac.uk; Thomson, Angela B.; Saran, Frank; Kelsey, Tom W.

    2005-07-01

    Purpose: To predict the age at which ovarian failure is likely to develop after radiation to a field that includes the ovary in women treated for cancer. Methods and Materials: Modern computed tomography radiotherapy planning allows determination of the effective dose of radiation received by the ovaries. Together with our recent assessment of the radiosensitivity of the human oocyte, the effective surviving fraction of primordial oocytes can be determined and the age of ovarian failure, with 95% confidence limits, predicted for any given dose of radiotherapy. Results: The effective sterilizing dose (ESD: dose of fractionated radiotherapy [Gy] at which premature ovarian failure occurs immediately after treatment in 97.5% of patients) decreases with increasing age at treatment. ESD at birth is 20.3 Gy; at 10 years 18.4 Gy, at 20 years 16.5 Gy, and at 30 years 14.3 Gy. We have calculated 95% confidence limits for age at premature ovarian failure for estimated radiation doses to the ovary from 1 Gy to the ESD from birth to 50 years. Conclusions: We report the first model to reliably predict the age of ovarian failure after treatment with a known dose of radiotherapy. Clinical application of this model will enable physicians to counsel women on their reproductive potential following successful treatment.

  10. Lumped and Distributed Parameter SPICE Models of TE Devices Considering Temperature Dependent Material Properties

    E-Print Network [OSTI]

    D. Mitrani; J. Salazar; A. Turo; M. J. García; J. A. Chávez

    2008-01-07

    Based on simplified one-dimensional steady-state analysis of thermoelectric phenomena and on analogies between thermal and electrical domains, we propose both lumped and distributed parameter electrical models for thermoelectric devices. For lumped parameter models, constant values for material properties are extracted from polynomial fit curves evaluated at different module temperatures (hot side, cold side, average, and mean module temperature). For the case of distributed parameter models, material properties are calculated according to the mean temperature at each segment of a sectioned device. A couple of important advantages of the presented models are that temperature dependence of material properties is considered and that they can be easily simulated using an electronic simulation tool such as SPICE. Comparisons are made between SPICE simulations for a single-pellet module using the proposed models and with numerical simulations carried out with Mathematica software. Results illustrate accuracy of the distributed parameter models and show how inappropriate is to assume, in some cases, constant material parameters for an entire thermoelectric element.

  11. A REVIEW OF SOFTWARE-INDUCED FAILURE EXPERIENCE.

    SciTech Connect (OSTI)

    CHU, T.L.; MARTINEZ-GURIDI, G.; YUE, M.; LEHNER, J.

    2006-09-01

    We present a review of software-induced failures in commercial nuclear power plants (NPPs) and in several non-nuclear industries. We discuss the approach used for connecting operational events related to these failures and the insights gained from this review. In particular, we elaborate on insights that can be used to model this kind of failure in a probabilistic risk assessment (PRA) model. We present the conclusions reached in these areas.

  12. 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; Phinney, Leslie M.; Piekos, Edward S.; Specht, Paul Elliott; Wixom, Ryan R.; Yarrington, Cole

    2015-01-01

    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.

  13. Weld failure detection

    DOE Patents [OSTI]

    Pennell, William E. (Unity Township, Westmoreland County, PA); Sutton, Jr., Harry G. (Mt. Lebanon, PA)

    1981-01-01

    Method and apparatus for detecting failure in a welded connection, particrly applicable to not readily accessible welds such as those joining components within the reactor vessel of a nuclear reactor system. A preselected tag gas is sealed within a chamber which extends through selected portions of the base metal and weld deposit. In the event of a failure, such as development of a crack extending from the chamber to an outer surface, the tag gas is released. The environment about the welded area is directed to an analyzer which, in the event of presence of the tag gas, evidences the failure. A trigger gas can be included with the tag gas to actuate the analyzer.

  14. A Numerical Model of the Temperature Field of the Cast and Solidified Ceramic Material

    SciTech Connect (OSTI)

    Kavicka, Frantisek; Sekanina, Bohumil; Stransky, Karel; Stetina, Josef [Brno University of Technology, Brno, Technicka 2 (Czech Republic); Dobrovska, Jana [Technical University of Ostrava, Ostrava, Tr. 17.listopadu 17 (Czech Republic)

    2010-06-15

    Corundo-baddeleyit material (CBM)--EUCOR--is a heat- and wear-resistant material even at extreme temperatures. This article introduces a numerical model of solidification and cooling of this material in a non-metallic mould. The model is capable of determining the total solidification time of the casting and also the place of the casting which solidifies last. Furthermore, it is possible to calculate the temperature gradient in any point and time, and also determine the local solidification time and the solidification interval of any point. The local solidification time is one of the input parameters for the cooperating model of chemical heterogeneity. This second model and its application on samples of EUCOR prove that the applied method of measurement of chemical heterogeneity provides detailed quantitative information on the material structure and makes it possible to analyse the solidification process. The analysis of this process entails statistical processing of the results of the measurements of the heterogeneity of the components of EUCOR and performs correlation of individual components during solidification. The crystallisation process seems to be very complicated, where the macro- and microscopic segregations differ significantly. The verification of both numerical models was conducted on a real cast 350x200x400 mm block.

  15. FAILURE PREDICTION AND STRESS ANALYSIS OF MICROCUTTING TOOLS 

    E-Print Network [OSTI]

    Chittipolu, Sujeev

    2010-07-14

    -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...

  16. Better Bearing Housing Seals Prevent Costly Machinery Failures 

    E-Print Network [OSTI]

    Bloch, H. P.

    1993-01-01

    of these failures could be prevented through the use of appropriately engineered, properly selected, and suitably installed bearing housing seals. Associated savings in labor, materials, and energy would accrue due to extended oil change intervals and a portion...

  17. Characterization and detection of incipient underground cable failures 

    E-Print Network [OSTI]

    Chaturbedi, Ritesh

    2002-01-01

    For distribution systems, failure of an underground cable results in an unscheduled outage. An unscheduled outage costs a utility manpower and materials, and affects their reliability index. Thus, the need for an on-line, ...

  18. 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)

    2012-11-15

    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.

  19. Materials Science & Metallurgy Master of Philosophy, Materials Modelling, More information on http://www.msm.cam.ac.uk/phase-trans/2005/ODS.html

    E-Print Network [OSTI]

    Cambridge, University of

    Materials Science & Metallurgy Master of Philosophy, Materials Modelling, More information on http://www.msm.cam.ac.uk/phase-trans/2005/ODS.html Course MP4, Thermodynamics and Phase Diagrams, H. K. D. H. Bhadeshia Lecture 4 about a thousand atoms block. The atom probe technique collects the experimental data on an atom by atom

  20. 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

  1. Multidiscipline Modeling in Materials and Structures Multi-physics modeling and simulations of reactive melt infiltration process used

    E-Print Network [OSTI]

    Grujicic, Mica

    of reactive melt infiltration process used in fabrication of ceramic-matrix composites (CMCs) Mica Grujicic in fabrication of ceramic-matrix composites (CMCs)", Multidiscipline Modeling in Materials and Structures, Vol used in fabrication of ceramic-matrix composites (CMCs) Mica Grujicic, Rohan Galgalikar, S. Ramaswami

  2. Synergistic failure of BWR internals

    SciTech Connect (OSTI)

    A. G. Ware; T. Y. Chang

    1999-10-25

    Boiling Water Reactor (BWR) core shrouds and other reactor internals important to safety are experiencing intergranular stress corrosion cracking (IGSCC). The United States Nuclear Regulatory Commission has followed the problem, and as part of its investigations, contracted with the Idaho National Engineering and Environmental Laboratory to conduct a risk assessment. The overall project objective is to assess the potential consequences and risks associated with the failure of IGSCC-susceptible BWR vessel internals, with specific consideration given to potential cascading and common mode effects. An initial phase has been completed in which background material was gathered and evaluated, and potential accident sequences were identified. A second phase is underway to perform a simplified, quantitative probabilistic risk assessment on a representative high-power BWR/4. Results of the initial study conducted on the jet pumps show that any cascading failures would not result in a significant increase in the core damage frequency. The methodology is currently being extended to other major reactor internals components.

  3. Synergistic Failure of BWR Internals

    SciTech Connect (OSTI)

    Ware, Arthur Gates; Chang, T-Y

    1999-10-01

    Boiling Water Reactor (BWR) core shrouds and other reactor internals important to safety are experiencing intergranular stress corrosion cracking (IGSCC). The United States Nuclear Regulatory Commission has followed the problem, and as part of its investigations, contracted with the Idaho National Engineering and Environmental Laboratory to conduct a risk assessment. The overall project objective is to assess the potential consequences and risks associated with the failure of IGSCC-susceptible BWR vessel internals, with specific consideration given to potential cascading and common mode effects. An initial phase has been completed in which background material was gathered and evaluated, and potential accident sequences were identified. A second phase is underway to perform a simplified, quantitative probabilistic risk assessment on a representative high-power BWR/4. Results of the initial study conducted on the jet pumps show that any cascading failures would not result in a significant increase in the core damage frequency. The methodology is currently being extended to other major reactor internals components.

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

    SciTech Connect (OSTI)

    English, Shawn Allen

    2014-09-01

    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.

  5. 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

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

    E-Print Network [OSTI]

    Gagliardini, Olivier

    Modelling the mechanical interaction between flowing materials and retaining wire structures Franc Sols Solides Structures, UJF-INPG-CNRS, Grenoble, France Received 10 March 2004; received in revised, design of structural elements may require analysing the mechanical interac- tion between a flowing

  7. 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

  8. 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

  9. Journal of Materials Processing Technology 146 (2004) 213220 A simulation model of gear skiving

    E-Print Network [OSTI]

    Aristomenis, Antoniadis

    2004-01-01

    Journal of Materials Processing Technology 146 (2004) 213­220 A simulation model of gear skiving A are doubtlessly premium well designed and properly fabricated gears. The desired gear quality is performed. One of the most adopted methods in gear finishing is a variation of hobbing, the so-called gear

  10. 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

  11. Mechanics of complex bodies: commentary on the unified modelling of material substructures

    E-Print Network [OSTI]

    Paolo Maria Mariano

    2008-03-26

    Basic issues of the general model-building framework of the mechanics of complex bodies are discussed. Attention is focused on the representation of the material elements, the conditions for the existence of ground states in conservative setting and the interpretation of the nature of the various balance laws occurring.

  12. A Pressure Relaxation Closure Model for One-Dimensional, Two-Material Lagrangian Hydrodynamics Based on

    E-Print Network [OSTI]

    Shashkov, Mikhail

    A Pressure Relaxation Closure Model for One-Dimensional, Two-Material Lagrangian Hydrodynamics Laboratory, Los Alamos, NM USA Abstract. Despite decades of development, Lagrangian hydrodynamics of strength of assigning sub-cell pressures to the physics associ- ated with the local, dynamic evolution. We package our

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

    E-Print Network [OSTI]

    such as ceramic matrix composites (CMC's) are currently being studied for their use in a wide rangeEstimation of Distributed Parameters in Permittivity Models of Composite Dielectric Materials Using the feasibility of quantifying properties of a composite dielectric ma- terial through the reflectance, where

  14. Micromechanics-based elastic model for functionally graded materials with particle interactions

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    : particle­matrix zone and transition zone. In the particle­matrix zone, pair-wise interactions be- tween. Keywords: Functionally graded materials; Composites; Micromechanical modeling; Elastic behavior; Pair- functional tasks by virtue of spatially tailored micro- structures. For instance, in a ceramic/metal FGM

  15. 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

  16. A penny-shaped cohesive crack model for material damage G. Wang, S.F. Li *

    E-Print Network [OSTI]

    Li, Shaofan

    A penny-shaped cohesive crack model for material damage G. Wang, S.F. Li * Department of Civil solids with ran- domly distributed penny-shaped cohesive micro-cracks (Barenblatt­Dugdale type). Energy are derived based on homogenization of randomly distributed penny-shaped cohesive cracks (Barenblatt

  17. The unifying role of dissipative action in the dynamic failure of solids

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Grady, Dennis

    2015-05-19

    Dissipative action, the product of dissipation energy and transport time, is fundamental to the dynamic failure of solids. Invariance of the dissipative action underlies the fourth-power nature of structured shock waves observed in selected solid metals and compounds. Dynamic failure through shock compaction, tensile spall and adiabatic shear are also governed by a constancy of the dissipative action. This commonality underlying the various modes of dynamic failure is described and leads to deeper insights into failure of solids in the intense shock wave event. These insights are in turn leading to a better understanding of the shock deformation processes underlyingmore »the fourth-power law. Experimental result and material models encompassing the dynamic failure of solids are explored for the purpose of demonstrating commonalities leading to invariance of the dissipation action. As a result, calculations are extended to aluminum and uranium metals with the intent of predicting micro-scale energetics and spatial scales in the structured shock wave.« less

  18. A Strength Model and Service Envelope for PBX 9501

    SciTech Connect (OSTI)

    Stevens, Ralph

    2014-02-05

    An analytical method is proposed for making an assessment of the severity of the response of PBX 9501 in structural response simulations. The approach is based on the coherent use of a strength model and a failure criterion. The strength model is based on a creep rupture function and an associated cumulative damage model. The material's residual strength at any time during a simulation of structural response is determined by taking into account both the actual stress history up to that time, and a hypothetical continuation of the applied stresses that are assumed to grow until material failure results. The residual strength is used by the failure criterion to define the region of safe (non-failed) material response. The Mohr-Coulomb failure criterion is chosen for its general applicability to materials with both cohesive and frictional strength. The combined use of the residual strength model and the failure criterion provides a quantitative method of assessing the severity of the response of PBX 9501 material in structural simulations: the proximity of any evolving, general state of stress to the failure surface (which shrinks due to the cumulative damage caused by the past stress history) can be calculated and used as a measure of margin to failure. The strength model has been calibrated to a broad range of uniaxial tension and compression tests, and a small set of creep tests, and is applicable to a broad range of loading conditions.

  19. Manufacturing process modeling for composite materials and structures, Sandia blade reliability collaborative

    SciTech Connect (OSTI)

    Guest, Daniel A.; Cairns, Douglas S.

    2014-02-01

    The increased use and interest in wind energy over the last few years has necessitated an increase in the manufacturing of wind turbine blades. This increase in manufacturing has in many ways out stepped the current understanding of not only the materials used but also the manufacturing methods used to construct composite laminates. The goal of this study is to develop a list of process parameters which influence the quality of composite laminates manufactured using vacuum assisted resin transfer molding and to evaluate how they influence laminate quality. Known to be primary factors for the manufacturing process are resin flow rate and vacuum pressure. An incorrect balance of these parameters will often cause porosity or voids in laminates that ultimately degrade the strength of the composite. Fiber waviness has also been seen as a major contributor to failures in wind turbine blades and is often the effect of mishandling during the lay-up process. Based on laboratory tests conducted, a relationship between these parameters and laminate quality has been established which will be a valuable tool in developing best practices and standard procedures for the manufacture of wind turbine blade composites.

  20. 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

    2002-03-19

    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.

  1. Three essays on business failure: causality and prediction 

    E-Print Network [OSTI]

    Zhang, Jin

    2009-05-15

    This dissertation investigates three issues on business failure causality and prediction. First, a nonlinear model for mathematical programming based discriminant analysis is studied. This study proposes a nonlinear model ...

  2. 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.

    1997-12-01

    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.

  3. 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

    2008-04-01

    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.

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

    SciTech Connect (OSTI)

    Luscher, Darby J; Bronkhorst, Curt A; Mc Dowell, David L

    2009-01-01

    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.

  5. “Playboy Bunny” Sign of Congestive Heart Failure

    E-Print Network [OSTI]

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

    2011-01-01

    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;

  6. Combination stem cell therapy for heart failure

    E-Print Network [OSTI]

    2010-01-01

    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

  7. Image-based stochastic modeling of the 3D morphology of energy materials on various length scales

    E-Print Network [OSTI]

    Schmidt, Volker

    Image-based stochastic modeling of the 3D morphology of energy materials on various length scales tomography image data O. Stenzel et al., Modelling and Simulation in Materials Science and Engineering microstructure of compressed graphite electrodes 3D morphology of hybrid organic solar cells Charge transport

  8. 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

  9. A quadratic cumulative production model for the material balance of an abnormally pressured gas reservoir 

    E-Print Network [OSTI]

    Gonzalez, Felix Eduardo

    2005-02-17

    -1 A QUADRATIC CUMULATIVE PRODUCTION MODEL FOR THE MATERIAL BALANCE OF AN ABNORMALLY PRESSURED GAS RESERVOIR A Thesis by FELIX E. GONZALEZ ROMERO Submitted to the Office of Graduate Studies of Texas A&M University... OF AN ABNORMALLY PRESSURED GAS RESERVOIR A Thesis by FELIX E. GONZALEZ ROMERO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE...

  10. Reassessment of the BWR scram failure probability

    SciTech Connect (OSTI)

    Burns, E.T.

    1989-01-01

    As part of the Severe Accident Policy Statement implementation, the probabilistic quantification of accident sequence frequencies that may lead to core damage is a key element in demonstrating a plant's safety status relative to US Nuclear Regulatory Commission (NRC) staff goals. One of the key quantitative inputs in a boiling water reactor (BWR) probabilistic risk assessment is the probability of a failure to scram. The assessment of this failure probability has been the subject of a long and continuing debate over the adequacy of available data and analytic modeling. This report provides a summary of the status of this debate, including the latest data, and provides a revision to the characterization of the failure probability originally published in NUREG 0460 and the Utility Group on Anticipated Transient Without Scram (ATWS) Petition.

  11. In-Service Design & Performance Prediction of Advanced Fusion Material Systems by Computational Modeling and Simulation

    SciTech Connect (OSTI)

    G. R. Odette; G. E. Lucas

    2005-11-15

    This final report on "In-Service Design & Performance Prediction of Advanced Fusion Material Systems by Computational Modeling and Simulation" (DE-FG03-01ER54632) consists of a series of summaries of work that has been published, or presented at meetings, or both. It briefly describes results on the following topics: 1) A Transport and Fate Model for Helium and Helium Management; 2) Atomistic Studies of Point Defect Energetics, Dynamics and Interactions; 3) Multiscale Modeling of Fracture consisting of: 3a) A Micromechanical Model of the Master Curve (MC) Universal Fracture Toughness-Temperature Curve Relation, KJc(T - To), 3b) An Embrittlement DTo Prediction Model for the Irradiation Hardening Dominated Regime, 3c) Non-hardening Irradiation Assisted Thermal and Helium Embrittlement of 8Cr Tempered Martensitic Steels: Compilation and Analysis of Existing Data, 3d) A Model for the KJc(T) of a High Strength NFA MA957, 3e) Cracked Body Size and Geometry Effects of Measured and Effective Fracture Toughness-Model Based MC and To Evaluations of F82H and Eurofer 97, 3-f) Size and Geometry Effects on the Effective Toughness of Cracked Fusion Structures; 4) Modeling the Multiscale Mechanics of Flow Localization-Ductility Loss in Irradiation Damaged BCC Alloys; and 5) A Universal Relation Between Indentation Hardness and True Stress-Strain Constitutive Behavior. Further details can be found in the cited references or presentations that generally can be accessed on the internet, or provided upon request to the authors. Finally, it is noted that this effort was integrated with our base program in fusion materials, also funded by the DOE OFES.

  12. LEWIS SPACECRAFT MISSION FAILURE INVESTIGATION BOARD

    E-Print Network [OSTI]

    Rhoads, James

    LEWIS SPACECRAFT MISSION FAILURE INVESTIGATION BOARD FINAL REPORT 12 February 1998 #12;II #12;III LEWIS SPACECRAFT MISSION FAILURE INVESTIGATION BOARD REPORT TABLE OF CONTENTS TOPIC PAGE EXECUTIVE Spacecraft Flight Operations and Failure Anomaly Timeline FACTORS DIRECTLY CONTRIBUTING TO FAILURE

  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

    2008-09-10

    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. Characterization, Modeling, and Energy Harvesting of Phase Transformations in Ferroelectric Materials

    E-Print Network [OSTI]

    Dong, Wen

    2015-01-01

    51 3.1.1. Materials and Specimen73 4.2.1. Materials and Specimenelectric field,” Smart Materials & Structures, 20(5), (

  15. 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.

    1984-01-01

    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.

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

    E-Print Network [OSTI]

    Alessandro Patti

    2010-06-04

    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.

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

    E-Print Network [OSTI]

    C. Fusco; T. Albaret; A. Tanguy

    2014-03-31

    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.

  18. 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

    2012-10-02

    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.

  19. Radiological Modeling for Determination of Derived Concentration Levels of an Area with Uranium Residual Material - 13533

    SciTech Connect (OSTI)

    Perez-Sanchez, Danyl [CIEMAT, Avenida Complutense 40, 28040, Madrid (Spain)] [CIEMAT, Avenida Complutense 40, 28040, Madrid (Spain)

    2013-07-01

    As a result of a pilot project developed at the old Spanish 'Junta de Energia Nuclear' to extract uranium from ores, tailings materials were generated. Most of these residual materials were sent back to different uranium mines, but a small amount of it was mixed with conventional building materials and deposited near the old plant until the surrounding ground was flattened. The affected land is included in an area under institutional control and used as recreational area. At the time of processing, uranium isotopes were separated but other radionuclides of the uranium decay series as Th-230, Ra-226 and daughters remain in the residue. Recently, the analyses of samples taken at different ground's depths confirmed their presence. This paper presents the methodology used to calculate the derived concentration level to ensure that the reference dose level of 0.1 mSv y-1 used as radiological criteria. In this study, a radiological impact assessment was performed modeling the area as recreational scenario. The modelization study was carried out with the code RESRAD considering as exposure pathways, external irradiation, inadvertent ingestion of soil, inhalation of resuspended particles, and inhalation of radon (Rn-222). As result was concluded that, if the concentration of Ra-226 in the first 15 cm of soil is lower than, 0.34 Bq g{sup -1}, the dose would not exceed the reference dose. Applying this value as a derived concentration level and comparing with the results of measurements on the ground, some areas with a concentration of activity slightly higher than latter were found. In these zones the remediation proposal has been to cover with a layer of 15 cm of clean material. This action represents a reduction of 85% of the dose and ensures compliance with the reference dose. (authors)

  20. Thirty-ninth Hawaii International Conference on System Sciences, January 2006, Kauai, Hawaii. c 2006 IEEE An estimator of propagation of cascading failure

    E-Print Network [OSTI]

    on a saturating branching process model of cascading failure and on failure data generated by the OPA simulation 2006 IEEE An estimator of propagation of cascading failure Ian Dobson, Kevin R. Wierzbicki, Benjamin A the extent to which failures propagate in cascading failures such as large blackouts. The estimator is tested

  1. Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil and Building Structures

    SciTech Connect (OSTI)

    Yu, Charley; Kamboj, Sunita; Wang, Cheng; Cheng, Jing-Jy

    2015-09-01

    This handbook is an update of the 1993 version of the Data Collection Handbook and the Radionuclide Transfer Factors Report to support modeling the impact of radioactive material in soil. Many new parameters have been added to the RESRAD Family of Codes, and new measurement methodologies are available. A detailed review of available parameter databases was conducted in preparation of this new handbook. This handbook is a companion document to the user manuals when using the RESRAD (onsite) and RESRAD-OFFSITE code. It can also be used for RESRAD-BUILD code because some of the building-related parameters are included in this handbook. The RESRAD (onsite) has been developed for implementing U.S. Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), crops and livestock, human intake, source characteristic, and building characteristic parameters are used in the RESRAD (onsite) code. The RESRAD-OFFSITE code is an extension of the RESRAD (onsite) code and can also model the transport of radionuclides to locations outside the footprint of the primary contamination. This handbook discusses parameter definitions, typical ranges, variations, and measurement methodologies. It also provides references for sources of additional information. Although this handbook was developed primarily to support the application of RESRAD Family of Codes, the discussions and values are valid for use of other pathway analysis models and codes.

  2. IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 16, NO. 4, AUGUST 2008 749 Characterization of Failures in an Operational

    E-Print Network [OSTI]

    Chuah, Chen-Nee

    of the different classes provides a probabilistic failure model, which can be used to generate realistic failureIEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 16, NO. 4, AUGUST 2008 749 Characterization of Failures services, its dependability in the presence of various failures becomes crit- ical. In this paper, we

  3. Micro-macro transition and simplified contact models for wet granular materials

    E-Print Network [OSTI]

    Sudeshna Roy; Abhinendra Singh; Stefan Luding; Thomas Weinhart

    2015-06-21

    Wet granular materials in a quasi-static steady state shear flow have been studied with discrete particle simulations. Macroscopic quantities, consistent with the conservation laws of continuum theory, are obtained by time averaging and spatial coarse-graining. Initial studies involve understanding the effect of liquid content and liquid properties like the surface tension on the macroscopic quantities. Two parameters of the liquid bridge contact model have been studied as the constitutive parameters that define the structure of this model (i) the rupture distance of the liquid bridge model, which is proportional to the liquid content, and (ii) the maximum adhesive force, as controlled by the surface tension of the liquid. Subsequently a correlation is developed between these micro parameters and the steady state cohesion in the limit of zero confining pressure. Furthermore, as second result, the macroscopic torque measured at the walls, which is an experimentally accessible parameter, is predicted from our simulation results as a dependence on the micro-parameters. Finally, the steady state cohesion of a realistic non-linear liquid bridge contact model scales well with the steady state cohesion for a simpler linearized irreversible contact model with the same maximum adhesive force and equal energy dissipated per contact.

  4. 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

  5. Utilization of Smart Materials and Predictive Modeling to Integrate Intracellular Dynamics with Cell Biomechanics and Collective Tissue Behavior

    E-Print Network [OSTI]

    Movileanu, Liviu

    Utilization of Smart Materials and Predictive Modeling to Integrate Intracellular Dynamics polarization will be induced in individual cells using "smart substrates" and patterns in intracellular important structures inside cells. New "smart" material will be used to trigger changes to cell movement

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

    E-Print Network [OSTI]

    Lee, Moonsu

    2005-08-29

    -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...

  7. The Application of a Genetic Algorithm to Estimate Material Properties for Fire Modeling from Bench-Scale Fire Test Data 

    E-Print Network [OSTI]

    Lautenberger, Chris; Rein, Guillermo; Fernandez-Pello, Carlos

    A methodology based on an automated optimization technique that uses a genetic algorithm (GA) is developed to estimate the material properties needed for CFD-based fire growth modeling from bench-scale fire test data. ...

  8. 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, ...

  9. 3.22 Mechanical Properties of Materials, Spring 2004

    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, ...

  10. A pressure relaxation closure model for one-dimensional, two-material Lagrangian hydrodynamics based on the Riemann problem

    SciTech Connect (OSTI)

    Kamm, James R [Los Alamos National Laboratory; Shashkov, Mikhail J [Los Alamos National Laboratory

    2009-01-01

    Despite decades of development, Lagrangian hydrodynamics of strengthfree materials presents numerous open issues, even in one dimension. We focus on the problem of closing a system of equations for a two-material cell under the assumption of a single velocity model. There are several existing models and approaches, each possessing different levels of fidelity to the underlying physics and each exhibiting unique features in the computed solutions. We consider the case in which the change in heat in the constituent materials in the mixed cell is assumed equal. An instantaneous pressure equilibration model for a mixed cell can be cast as four equations in four unknowns, comprised of the updated values of the specific internal energy and the specific volume for each of the two materials in the mixed cell. The unique contribution of our approach is a physics-inspired, geometry-based model in which the updated values of the sub-cell, relaxing-toward-equilibrium constituent pressures are related to a local Riemann problem through an optimization principle. This approach couples the modeling problem of assigning sub-cell pressures to the physics associated with the local, dynamic evolution. We package our approach in the framework of a standard predictor-corrector time integration scheme. We evaluate our model using idealized, two material problems using either ideal-gas or stiffened-gas equations of state and compare these results to those computed with the method of Tipton and with corresponding pure-material calculations.

  11. 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.

    1981-01-01

    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.

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

    E-Print Network [OSTI]

    V. M. Mostepanenko

    2014-11-17

    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.

  13. Modeling and simulation of electronic structure, material interface and random doping in nano-electronic devices

    SciTech Connect (OSTI)

    Chen Duan [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Wei Guowei [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 (United States)], E-mail: wei@math.msu.edu

    2010-06-20

    The miniaturization of nano-scale electronic devices, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. Modeling and simulation of this class of problems have emerged as an important topic in applied and computational mathematics. This work presents mathematical models and computational algorithms for the simulation of nano-scale MOSFETs. We introduce a unified two-scale energy functional to describe the electrons and the continuum electrostatic potential of the nano-electronic device. This framework enables us to put microscopic and macroscopic descriptions in an equal footing at nano-scale. By optimization of the energy functional, we derive consistently coupled Poisson-Kohn-Sham equations. Additionally, layered structures are crucial to the electrostatic and transport properties of nano-transistors. A material interface model is proposed for more accurate description of the electrostatics governed by the Poisson equation. Finally, a new individual dopant model that utilizes the Dirac delta function is proposed to understand the random doping effect in nano-electronic devices. Two mathematical algorithms, the matched interface and boundary (MIB) method and the Dirichlet-to-Neumann mapping (DNM) technique, are introduced to improve the computational efficiency of nano-device simulations. Electronic structures are computed via subband decomposition and the transport properties, such as the I-V curves and electron density, are evaluated via the non-equilibrium Green's functions (NEGF) formalism. Two distinct device configurations, a double-gate MOSFET and a four-gate MOSFET, are considered in our three-dimensional numerical simulations. For these devices, the current fluctuation and voltage threshold lowering effect induced by the discrete dopant model are explored. Numerical convergence and model well-posedness are also investigated in the present work.

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

    E-Print Network [OSTI]

    Wolf, Malima Isabelle, 1981-

    2011-01-01

    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 ...

  15. FRACTURE FAILURE CRITERIA OF SOFC PEN STRUCTURE

    SciTech Connect (OSTI)

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

    2007-04-30

    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.

  16. Failure Inferencing based Fast Rerouting for Handling Transient Link and Node Failures

    E-Print Network [OSTI]

    Nelakuditi, Srihari

    generation, propagation, and processing mechanisms. MPLS based approaches [5] handle transient failures1 Failure Inferencing based Fast Rerouting for Handling Transient Link and Node Failures Zifei network with high service availability. Unfortunately, in today's Internet, transient failures occur

  17. Multiresonance and chaotic behavior analysis for polarization in material modeled by multifrequency excitations duffing oscillator

    E-Print Network [OSTI]

    C. Ainamon; C. H. Miwadinou; A. V. Monwanou; J. B. Chabi Orou

    2014-02-14

    This paper considers nonlinear dynamics of polarization oscillations when some materials when they are subjected to the action of an electromagnetic wave modeled by multifrequency forced Duffing equation. Multiresonance and chaotic behavior are analysed. For analysis of the case of resonance, the method of multiple scales is used and it has been found from the equation of the amplitudes for each of the possible resonance system. Possible resonances are inter alia the resonances or sub superharmonic, the primary resonance and other resonances called secondary. The phenomena of amplitude jump and hysteresis for polarization were observed and analyzed. Finally, the study of chaotic behavior for polarization was made by numerical simulation using the Runge- Kutta fourth order.

  18. Investigation of Possible Wellbore Cement Failures During Hydraulic Fracturing Operations

    SciTech Connect (OSTI)

    Kim, Jihoon; Moridis, George

    2014-11-01

    We model and assess the possibility of shear failure, using the Mohr-Coulomb model ? along the vertical well by employing a rigorous coupled flow-geomechanic analysis. To this end, we vary the values of cohesion between the well casing and the surrounding cement to representing different quality levels of the cementing operation (low cohesion corresponds to low-quality cement and/or incomplete cementing). The simulation results show that there is very little fracturing when the cement is of high quality.. Conversely, incomplete cementing and/or weak cement can causes significant shear failure and the evolution of long fractures/cracks along the vertical well. Specifically, low cohesion between the well and cemented areas can cause significant shear failure along the well, but the same cohesion as the cemented zone does not cause shear failure. When the hydraulic fracturing pressure is high, low cohesion of the cement can causes fast propagation of shear failure and of the resulting fracture/crack, but a high-quality cement with no weak zones exhibits limited shear failure that is concentrated near the bottom of the vertical part of the well. Thus, high-quality cement and complete cementing along the vertical well appears to be the strongest protection against shear failure of the wellbore cement and, consequently, against contamination hazards to drinking water aquifers during hydraulic fracturing operations.

  19. Autonomous thruster failure recovery for underactuated spacecraft

    E-Print Network [OSTI]

    Pong, Christopher Masaru

    2010-01-01

    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 ...

  20. 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

    2014-01-09

    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.

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

    SciTech Connect (OSTI)

    Peterson, Steven K

    2015-01-01

    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.

  2. An Estimator of Propagation of Cascading Failure

    SciTech Connect (OSTI)

    Dobson, Ian; Wierzbicki, Kevin; Carreras, Benjamin A; Lynch, Vickie E; Newman, David E

    2006-01-01

    The authors suggest a statistical estimator to measure the extent to which failures propagate in cascading failures such as large blackouts.

  3. Failure analysis issues in microelectromechanical systems (MEMS...

    Office of Scientific and Technical Information (OSTI)

    Conference: Failure analysis issues in microelectromechanical systems (MEMS). Citation Details In-Document Search Title: Failure analysis issues in microelectromechanical systems...

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

    SciTech Connect (OSTI)

    Hale, Steve

    2013-09-11

    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.

  5. Statistical analysis of cascading failures in power grids

    SciTech Connect (OSTI)

    Chertkov, Michael; Pfitzner, Rene; Turitsyn, Konstantin

    2010-12-01

    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.

  6. The value of numerical modeling in understanding the complete load/deformation behavior of cohesive-frictional materials

    SciTech Connect (OSTI)

    Potyondy, D.O.; Fairhurst, C.E.

    1999-07-01

    The post-peak load/deformation behavior of cohesive-frictional materials is an integral part of the overall response of a specimen to compressive loading. A more comprehensive understanding of the pre- and post-peak behavior is necessary. Recent developments in numerical modeling that allow study of the overall response of a synthetic material containing discrete heterogeneities and discontinuities both at the micro (particle) scale and at the larger scale of jointed rock masses can greatly aid the interpretation and application of laboratory test results on these materials.

  7. Modeling the viscoplastic micromechanical response of two-phase materials using fast Fourier transforms

    SciTech Connect (OSTI)

    Lebensohn, Ricardo A; Lee, Sukbin; Rollett, Anthony D

    2009-01-01

    A viscoplastic approach using the Fast Fourier Transform (FFT) method for obtaining local mechanical response is utilized to study microstructure-property relationships in composite materials. Specifically, three-dimensional, two-phase digital materials containing isotropically coarsened particles surrounded by a matrix phase, generated through a Kinetic Monte Carlo Potts model for Ostwald ripening, are used as instantiations in order to calculate the stress and strain rate fields under uniaxial tension. The effects of the morphology of the matrix phase, the volume fraction and the contiguity of particles, and the polycrystallinity of matrix phase, on the stress and strain rate fields under uniaxial tension are examined. It is found that the first moments of the stress and strain rate fields have a different dependence on the particle volume fraction and the particle contiguity from their second moments. The average stresses and average strain rates of both phases and of the overall composite have rather simple relationships with the particle volume fraction whereas their standard deviations vary strongly, especially when the particle volume fraction is high, and the contiguity of particles has a noticeable effect on the mechanical response. It is also found that the shape of stress distribution in the BCC hard particle phase evolves as the volume fraction of particles in the composite varies, such that it agrees with the stress field in the BCC polycrystal as the volume of particles approaches unity. Finally, it is observed that the stress and strain rate fields in the microstructures with a polycrystalline matrix are less sensitive to changes in volume fraction and contiguity of particles.

  8. Material characterization and modeling for piezoelectric actuation and power generation under high electromechanical driving levels

    E-Print Network [OSTI]

    Lin, Ching-Yu, 1972-

    2002-01-01

    High electromechanical loads parallel to piezoelectric polarization might result in depolarization of the material, depending on the material property itself and the external excitations such as electrical field, electrical ...

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

    E-Print Network [OSTI]

    Song, Zhenhuan

    2013-07-01

    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. ...

  10. 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

    2013-08-13

    -viscoplastic, and thermo-viscodamaged materials, while the aggregate is considered to be a linear, isotropic elastic material. The 2D RVEs were used to study the effects of variation in aggregate shape, distribution, volume fraction, ITZ strength, strain rate... Page Figure IV-19. Damage density distribution of asphalt concrete models with tensile strain rates (50% aggregate volume fraction and T=20 ?C): (a) 10-6/second, (b) 10-5/second, (c) 10-4/second, and (d) 10...

  11. Parameters identification in strain-rate and thermal sensitive visco-plastic material model for an alumina dispersion strengthened copper

    E-Print Network [OSTI]

    Scapin, M; Peroni, M

    2011-01-01

    The main objective of this paper is getting strain-hardening, thermal and strain-rate parameters for a material model in order to correctly reproduce the deformation process that occurs in high strain-rate scenario, in which the material reaches also high levels of plastic deformation and temperature. In particular, in this work the numerical inverse method is applied to extract material strength parameters from experimental data obtained via mechanical tests at different strain-rates (from quasi-static loading to high strain-rate) and temperatures (between 20 C and 1000 C) for an alumina dispersion strengthened copper material, which commercial name is GLIDCOP. Thanks to its properties GLIDCOP finds several applications in particle accelerator technologies, where problems of thermal management, combined with structural requirements, play a key role. Currently, it is used for the construction of structural and functional parts of the particle beam collimation system. Since the extreme condition in which the m...

  12. Three-dimensional numerical models with varied material properties and erosion rates: Implications for the mechanics and kinematics

    E-Print Network [OSTI]

    Mueller, Karl

    for the mechanics and kinematics of compressive wedges Phaedra Upton,1,2 Karl Mueller,3 and Yue-Gau Chen4 Received develop three-dimensional mechanical models of a compressive wedge and investigate how the form and kinematics of the outboard wedge are affected by variation in initial topography, material properties

  13. 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.

    2012-07-01

    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.

  14. Modeling the influence of river rehabilitation scenarios on bed material sediment flux in a large river over decadal timescales

    E-Print Network [OSTI]

    Singer, Michael

    Modeling the influence of river rehabilitation scenarios on bed material sediment flux in a large and calibrated sediment transport formulae were used to assess the decadal impact of major river rehabilitation the implementation of three major river rehabilitation strategies being considered in the Sacramento River Valley

  15. 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

  16. Supplemental Material ReadMe file: A user's guide for the vitality model with initial Gaussian distribution

    E-Print Network [OSTI]

    Washington at Seattle, University of

    Supplemental Material ReadMe file: A user's guide for the vitality model with initial Gaussian distribution parameter fitting routine and the R functions contained in file vitality.gaussian.R. Ting Li and James J. Anderson University of Washington June 11, 2009 The supplemental R file vitality

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

    E-Print Network [OSTI]

    Yang, Judy

    2012-01-01

    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. Failure Stress and Apparent Elastic Modulus of Diesel Particulate Filter Ceramics

    Broader source: Energy.gov [DOE]

    Three established mechanical 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.

  19. New Ferroelectrics for Naval SONAR and Modeling of Nanoscale Ferroelectric Nonvolatile Memory Materials

    E-Print Network [OSTI]

    Rappe, Andrew M.

    devices. When such a material is deformed by underwater sound vibrations, it generates an electric field of structural, electrical and mechanical properties, making them vital materials for many technological in computer speed has made first- principles calculations a viable tool for understanding these complex

  20. Stochastic 3D Modeling of Non-Woven Materials with Wet-Proofing Agent

    E-Print Network [OSTI]

    Schmidt, Volker

    Institute of Stochastics, Ulm University, Germany bInstitute of Energy and Climate Research (IEK-3: Electrochemical Process for Materials and Energy (HZB), Germany dFa. Freudenberg Fuel Cell Components Technology KG (FFCCT), Germany e Engineering), Forschungszentrum J¨ulich GmbH, Germany cInstitute of Applied Materials, Helmholtz Centre Berlin

  1. 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.

    2011-03-28

    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.

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

    E-Print Network [OSTI]

    Zhang, Jinsong, 1975-

    2001-01-01

    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 ...

  3. Dynamic simulation of heart mitral valve with transversely isotropic material model

    E-Print Network [OSTI]

    Weinberg, Eli, 1979-

    2005-01-01

    This thesis develops two methods for simulating, in the finite element setting, the material behavior of heart mitral valve leaflet tissue. First, a mixed pressure-displacement formulation is used to implement the constitutive ...

  4. 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

    2012-03-20

    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.

  5. 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

    2010-01-01

    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.

  6. 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

    2010-10-28

    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.

  7. Role of microbial induced corrosion in subsea water pipeline failure

    SciTech Connect (OSTI)

    Samant, A.K.; Singh, S.K.

    1998-12-31

    Premature failure of subsea water injection pipelines due to rupture was observed in Indian offshore facilities. In this connection various contributing factors like metallurgy of pipeline, operating conditions and corrosion related parameters have been examined. Material defects that can lead to premature failure of pipelines like microstructural anomalies, variation in hardness and elemental composition and tensile strength etc. have been found within the specified limits of material specification. Analysis of various operating parameters and water quality data indicated failure due to microbial induced internal corrosion. Due to low flow velocities, suspended insoluble corrosion products, bacteria and other microbes, present in the water, accumulated inside the pipeline surface mostly in low areas. Deposit provided hiding place for bacteria and shielded them from effective treatment by bactericide. Deposits also resulted in the formation of oxygen concentration cells resulting in localized corrosion. Non-pigging of pipe lines, even after long shut down, also resulted in accumulation of deposits. During this period, microbial activities dominated resulting in the formation of acidic metabolizes which ultimately led to internal corrosion. In this paper, all above aspects have been examined with special reference to the role of microbiologically induced corrosion for failure of subsea water injection pipe lines.

  8. Modeling investigation of the stability and irradiation-induced evolution of nanoscale precipitates in advanced structural materials

    SciTech Connect (OSTI)

    Wirth, Brian

    2015-04-08

    Materials used in extremely hostile environment such as nuclear reactors are subject to a high flux of neutron irradiation, and thus vast concentrations of vacancy and interstitial point defects are produced because of collisions of energetic neutrons with host lattice atoms. The fate of these defects depends on various reaction mechanisms which occur immediately following the displacement cascade evolution and during the longer-time kinetically dominated evolution such as annihilation, recombination, clustering or trapping at sinks of vacancies, interstitials and their clusters. The long-range diffusional transport and evolution of point defects and self-defect clusters drive a microstructural and microchemical evolution that are known to produce degradation of mechanical properties including the creep rate, yield strength, ductility, or fracture toughness, and correspondingly affect material serviceability and lifetimes in nuclear applications. Therefore, a detailed understanding of microstructural evolution in materials at different time and length scales is of significant importance. The primary objective of this work is to utilize a hierarchical computational modeling approach i) to evaluate the potential for nanoscale precipitates to enhance point defect recombination rates and thereby the self-healing ability of advanced structural materials, and ii) to evaluate the stability and irradiation-induced evolution of such nanoscale precipitates resulting from enhanced point defect transport to and annihilation at precipitate interfaces. This project will utilize, and as necessary develop, computational materials modeling techniques within a hierarchical computational modeling approach, principally including molecular dynamics, kinetic Monte Carlo and spatially-dependent cluster dynamics modeling, to particular, the interfacial structure of embedded nanoscale precipitates will be evaluated by electronic- and atomic-scale modeling methods, and the efficiency of the validated interfaces for trapping point defects will next be evaluated by atomic-scale modeling (e.g., determining the sink strength of the precipitates), addressing key questions related to the optimal interface characteristics to attract point defects and enhance their recombination. Kinetic models will also be developed to simulate microstructural evolution of the nanoscale features and irradiation produced defect clusters, and compared with observed microstructural changes.

  9. Failure of Tapo Canyon Tailings Dam

    E-Print Network [OSTI]

    Harder, Leslie F Jr; Stewart, Jonathan P

    1996-01-01

    failures of Chilean tailings dams." J. Soil Mech. and Found.earthquake failure of a tailings dam due to liquefaction offailure of the Tapo Canyon tailings dam was one of the most

  10. Individual Reactions to Failure in Virtual Teams 

    E-Print Network [OSTI]

    Diaz, Ismael

    2012-02-14

    This project examines the relationship between team identification and collaboration configuration and how they affect attributions to failure. In a sample of 110 participants, we examined reactions to failure. We manipulated perceptions...

  11. Failure prediction of cross-rolled beryllium sheets subjected to transverse point loads 

    E-Print Network [OSTI]

    Mascorro, Edward

    1991-01-01

    advantage of this formulation is its ability to take into account interdependence of the failure stress components. Previous theories assume that biaxially loaded specimens have failure surfaces that are only functions of the uniaxial failure stresses.... It is shown in section 2 that cross-rolled beryllium is stronger when it is loaded biaxially than when loaded uniaxially. Although previous theories can not describe this phenomenon, the Tsai-Wu formulation is simple yet flexible enough to model...

  12. Introduction to Microelectromechanical Systems (MEMS) failure...

    Office of Scientific and Technical Information (OSTI)

    Conference: Introduction to Microelectromechanical Systems (MEMS) failure analysis. Citation Details In-Document Search Title: Introduction to Microelectromechanical Systems (MEMS)...

  13. 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

    1982-01-01

    Projectiles on Helicopter Composite Material Rotor Blades. (December 1982) Tilden Newton Nikel, B. S. , Texas AAM University; N . S . , Texas A&N University Chairman of Advisory Committee: Dr. Clarence L. Hough Jr. A number of damage models have been.... 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...

  14. Winning the fight against boiler tube failure

    SciTech Connect (OSTI)

    Cohen, J.; Dooley, B.

    1986-12-01

    Eliminating boiler tube failures could be worth $5 billion a year to the electric power industry. The causes and cures for the great majority of these ubiquitous failures are now known, with implications for change ranging from senior management to the maintenance crew. Methods for preventing boiler tube failure are discussed.

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

    E-Print Network [OSTI]

    Rokohl, Don Richard

    1984-01-01

    Flood, West Virginia Aberfsn Flow Slide, Wales Mochikoshi Tailings Dam, Japan A LITERATURE REVIEW OF EXISTING FLOOD ROUTING MODELS Theoretical Flood Routing Analysis Models Models Developed for Turbulent Flow Analysis U. S. Army Corps of Engineers... Front of Water Retaining Dam Showing Breach Formation 13 Characteristics of Bingham Plastic Model Characteristics of Modified Ramberg-Osgood Nodel Weight versus Velocity for Bunker Hill Tailings Vened Coaxial Viscometer 23 25 27 28 Comparison...

  16. Failure by fracture and fatigue in "NANO" and "BIO" materials

    E-Print Network [OSTI]

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

    2003-01-01

    structures for microelectromechanical systems (MEMS), andstructures for microelectromechanical systems (MEMS),

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

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

    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 hypersonic flights...

  18. Power Grid Defense Against Malicious Cascading Failure

    E-Print Network [OSTI]

    Shakarian, Paulo; Lindelauf, Roy

    2014-01-01

    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...

  19. Understanding Automotive Exhaust Catalysts Using a Surface Science Approach: Model NOx Storage Materials

    SciTech Connect (OSTI)

    Szanyi, Janos; Yi, Cheol-Woo W.; Mudiyanselage, Kumudu K.; Kwak, Ja Hun

    2013-11-01

    The structure-reactivity relationships of model BaO-based NOx storage/reduction catalysts were investigated under well controlled experimental conditions using surface science analysis techniques. The reactivity of BaO toward NO2, CO2, and H2O was studied as a function of BaO layer thickness [0\\hBaO\\30 monolayer (ML)], sample temperature, reactant partial pressure, and the nature of the substrate the NOx storage material was deposited onto. Most of the efforts focused on understanding the mechanism of NO2 storage either on pure BaO, or on BaO exposed to CO2 or H2O prior to NO2 exposure. The interaction of NO2 with a pure BaO film results in the initial formation of nitrite/nitrate ion pairs by a cooperative adsorption mechanism predicted by prior theoretical calculations. The nitrites are then further oxidized to nitrates to produce a fully nitrated surface. The mechanism of NO2 uptake on thin BaO films (\\4 ML), BaO clusters (\\1 ML) and mixed BaO/Al2O3 layers are fundamentally different: in these systems initially nitrites are formed only, and then converted to nitrates at longer NO2 exposure times. These results clarify the contradicting mechanisms presented in prior studies in the literature. After the formation of a nitrate layer the further conversion of the underlying BaO is slow, and strongly depends on both the sample temperature and the NO2 partial pressure. At 300 K sample temperature amorphous Ba(NO3)2 forms that then can be converted to crystalline nitrates at elevated temperatures. The reaction between BaO and H2O is facile, a series of Ba(OH)2 phases form under the temperature and H2O partial pressure regimes studied. Both amorphous and crystalline Ba(OH)2 phases react with NO2, and initially form nitrites only that can be converted to nitrates. The NO2 adsorption capacities of BaO and Ba(OH)2 are identical, i.e., both of these phases can completely be converted to Ba(NO3)2. In contrast, the interaction of CO2 with pure BaO results in the formation of a BaCO3 layer that prevents to complete carbonation of the entire BaO film under the experimental conditions applied in these studies. However, these ‘‘carbonated’’ BaO layers readily react with NO2, and at elevated sample temperature even the carbonate layer is converted to nitrates. The importance of the metal oxide/metal interface in the chemistry on NOx storage-reduction catalysts was studied on BaO(\\1 ML)/Pt(111) reverse model catalysts. In comparison to the clean Pt(111), new oxygen adsorption phases were identified on the BaO/Pt(111) surface that can be associated with oxygen atoms strongly adsorbed on Pt atoms at the peripheries of BaO particles. A simple kinetic model developed helped explain the observed thermal desorption results. The role of the oxide/metal interface in the reduction of Ba(NO3)2 was also substantiated in experiments where Ba(NO3)2/O/Pt(111) samples were exposed to CO at elevated sample temperature. The catalytic decomposition of the nitrate phase occurred as soon as metal sites opened up by the removal of interfacial oxygen via CO oxidation from the O/Pt(111) surface. The temperature for catalytic nitrate reduction was found to be significantly lower than the onset temperature of thermal nitrate decomposition. We gratefully acknowledge the US Department of Energy (DOE), Office of Science, Division of Chemical Sciences, Geosciences, and Biosciences for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national user facility sponsored by the DOE Office of Biological and Environmental Research and located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle under contract number DE-AC05-76RL01830.

  20. An Instability Leading to Failure of Polyethylene in Uniaxial Creep

    E-Print Network [OSTI]

    An Instability Leading to Failure of Polyethylene in Uniaxial Creep L. J. ZAPAS and J. M. CRISSMAN model, a point of instability is pre- dicted for the uniaxial creep of high density polyethylene. From dead load experiments it has been found that the instabil- ity occurs for linear -polyethylene

  1. CHOU SYMPOSIUM Material Modeling and Dynamic-Response Analysis of Resin-starved Cross-

    E-Print Network [OSTI]

    Grujicic, Mica

    . Bell, Patrick S. Glomski International Center for Automotive Research CU-ICAR, Department of Mechanical-literature mechanical property data for the constituent materials and the available processing and are widely used in aerospace, construction, automotive, sporting-goods and defense related industries

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

    E-Print Network [OSTI]

    Grujicic, Mica

    to design and fabricate personnel carriers with higher landmine-detonation survivability characteristics-mining equipment and personnel protection gear used in landmine clearing are expected to benefit from a better to blast loading including the role of target design and use of blast attenuation materials; (c

  3. Comprehensive Physical Models and Simulation Package for Plasma/Material Interactions during Plasma Instabilities"

    E-Print Network [OSTI]

    Harilal, S. S.

    "m, roydty.free license to publish or rmroduca the published form of this contribution. or allow othws to do of Nuclear Materials. "Work is supported by the U.S. Department of Energy, Office of Fusion Energy. #12 Energy interaction with Qeneral Heterogeneous ~arget ~ystems (HEIGHTS) has been developed and consists

  4. Characterization, Modeling, and Energy Harvesting of Phase Transformations in Ferroelectric Materials

    E-Print Network [OSTI]

    Dong, Wen

    2015-01-01

    47 v 3. Characterization of FE R – FE O Phase Transformationand C. S. LYNCH, "CHARACTERIZATION AND MODELING OF RELAXORand C. S. Lynch, "Characterization of ferroelectric single

  5. 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...

  6. 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

  7. Rosetta Predictions in CASP5: Successes, Failures, and Prospects for Complete Automation

    E-Print Network [OSTI]

    Baker, David

    Rosetta Predictions in CASP5: Successes, Failures, and Prospects for Complete Automation Philip insertions; we describe here the successes as well as the failures in the context of current efforts target sequence. To generate template-based models, we used homologous structure information; insertions

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

    SciTech Connect (OSTI)

    Lewis, B.E.

    1984-09-01

    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.

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

    SciTech Connect (OSTI)

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

    2007-04-01

    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. Forward model calculations for determining isotopic compositions of materials used in a radiological dispersal device 

    E-Print Network [OSTI]

    Burk, David Edward

    2005-08-29

    of the RDD debris. The objective of this research was to benchmark a forward model methodology for predicting isotopic composition of spent nuclear fuel used in an RDD while at the same time optimizing the fidelity of the model to reduce computational time...

  11. 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.

  12. Analysis of damage and failure in metal matrix composites

    SciTech Connect (OSTI)

    Brust, F.W.; Majumdar, B.S.; Newaz, G.M.

    1995-12-31

    This paper presents the results of the analysis of the constitutive response of a model Metal Matrix Composite (MMC) system. The model is described first, followed by some direct comparison of predicted response to corresponding experimental data. An important result discussed here is that when model verification is made, it is important to compare load direction response to the experimental data, but also, comparisons to the out of load direction response must be made, or the model may not be performing as desired. Some discussion of failure predictions using simple models is also made here.

  13. Wear 252 (2002) 322331 A physically-based abrasive wear model for composite materials

    E-Print Network [OSTI]

    Ritchie, Robert

    2002-01-01

    brushes, cylinder liners, ar- tificial joints, and helicopter blades. Indeed, compared to monolithic-body (pin-on-drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy

  14. Sorption model of trichloroethylene (TCE) and benezene in municipal landfill materials 

    E-Print Network [OSTI]

    Chuang, Yuh-Lin

    1995-01-01

    This research is intended to establish a mathematical model describing the mass transfer of trace gas in landfill. Experimental data used for calibration were reported by Stiegler et al. [ 1989]. Transfer mechanisms of TCE and benzene (trace gases...

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

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    Progress In Electromagnetics Research B, Vol. 15, 197­215, 2009 MODELING OF SHIELDING COMPOSITE inclusions are required in many engineering applications, especially, for the design of microwave shielding enclosures to ensure electromagnetic compatibility and electromagnetic immunity. Herein, multilayer shielding

  16. Preliminary characterization of materials for a reactive transport model validation experiment

    SciTech Connect (OSTI)

    Siegel, M.D.; Ward, D.B.; Cheng, W.C.; Bryant, C.; Chocas, C.S.; Reynolds, C.G.

    1993-03-01

    The geochemical properties of a porous sand and several tracers (Ni, Br, and Li) have been characterized for use in a caisson experiment designed to validate sorption models used in models of inactive transport. The surfaces of the sand grains have been examined by a combination of techniques including potentiometric titration, acid leaching, optical microscopy, and scanning electron microscopy with energy-dispersive spectroscopy. The surface studies indicate the presence of small amounts of carbonate, kaolinite and iron-oxyhydroxides. Adsorption of nickel, lithium and bromide by the sand was measured using batch techniques. Bromide was not sorbed by the sand. A linear (K{sub d}) or an isotherm sorption model may adequately describe transport of Li; however, a model describing the changes of pH and the concentrations of other solution species as a function of time and position within the caisson and the concomitant effects on Ni sorption may be required for accurate predictions of nickel transport.

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

    SciTech Connect (OSTI)

    Cai, C.; Rodet, T.; Mohammad-Djafari, A.; Legoupil, S.

    2013-11-15

    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.

  18. IEEE TRANSACTIONS ON COMPONENTS, PACKAGING, AND MANUFACTURING TECHNOLOGY--PART C, VOL. 21, NO. 2, APRIL 1998 97 Material-Centric Modeling of PWB Fabrication

    E-Print Network [OSTI]

    Sandborn, Peter

    processes. Index Terms-- Cost modeling, design-for-environment (DFE), design-to-cost, material, Associate Member, IEEE Abstract--This paper presents an activity-based cost model for printed wiring board-based manufacturing cost models, activities are based on equipment and facilities ("equipment

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

    SciTech Connect (OSTI)

    Myers, John D.; Taylor, Ralph S.

    2012-06-26

    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.

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

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen

    2005-07-01

    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.

  1. Modeling how cells move together could inspire self-healing 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJessework uses concrete7 AssessmentBusinessAlternativeModelModelingArgonne

  2. 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

    2014-01-01

    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.

  3. 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

    2014-05-01

    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.

  4. Failure modes and effects analysis of fusion magnet systems

    SciTech Connect (OSTI)

    Zimmermann, M; Kazimi, M S; Siu, N O; Thome, R J

    1988-12-01

    A failure modes and consequence analysis of fusion magnet system is an important contributor towards enhancing the design by improving the reliability and reducing the risk associated with the operation of magnet systems. In the first part of this study, a failure mode analysis of a superconducting magnet system is performed. Building on the functional breakdown and the fault tree analysis of the Toroidal Field (TF) coils of the Next European Torus (NET), several subsystem levels are added and an overview of potential sources of failures in a magnet system is provided. The failure analysis is extended to the Poloidal Field (PF) magnet system. Furthermore, an extensive analysis of interactions within the fusion device caused by the operation of the PF magnets is presented in the form of an Interaction Matrix. A number of these interactions may have significant consequences for the TF magnet system particularly interactions triggered by electrical failures in the PF magnet system. In the second part of this study, two basic categories of electrical failures in the PF magnet system are examined: short circuits between the terminals of external PF coils, and faults with a constant voltage applied at external PF coil terminals. An electromagnetic model of the Compact Ignition Tokamak (CIT) is used to examine the mechanical load conditions for the PF and the TF coils resulting from these fault scenarios. It is found that shorts do not pose large threats to the PF coils. Also, the type of plasma disruption has little impact on the net forces on the PF and the TF coils. 39 refs., 30 figs., 12 tabs.

  5. Fluid flow modeling of resin transfer molding for composite material wind turbine blade structures.

    SciTech Connect (OSTI)

    Cairns, Douglas S. (Montana State University, Bozeman, MT); Rossel, Scott M. (Montana State University, Bozeman, MT)

    2004-06-01

    Resin transfer molding (RTM) is a closed mold process for making composite materials. It has the potential to produce parts more cost effectively than hand lay-up or other methods. However, fluid flow tends to be unpredictable and parts the size of a wind turbine blade are difficult to engineer without some predictive method for resin flow. There were five goals of this study. The first was to determine permeabilities for three fabrics commonly used for RTM over a useful range of fiber volume fractions. Next, relations to estimate permeabilities in mixed fabric lay-ups were evaluated. Flow in blade substructures was analyzed and compared to predictions. Flow in a full-scale blade was predicted and substructure results were used to validate the accuracy of a full-scale blade prediction.

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

    SciTech Connect (OSTI)

    Carbajo, Juan J; McDuffee, Joel Lee

    2013-01-01

    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.

  7. Presented at the 27th Leeds-Lyon Symposium on Tribology, Tribological Research: From Model Experiment to Industrial Problems: Mechanics, Materials Science, Physico-chemistry Lyon,

    E-Print Network [OSTI]

    Ã?agin, Tahir

    1 Presented at the 27th Leeds-Lyon Symposium on Tribology, Tribological Research: From Model Experiment to Industrial Problems: Mechanics, Materials Science, Physico-chemistry Lyon, France, September 5

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

    E-Print Network [OSTI]

    Thirumalai, Devarajan

    2008-01-01

    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

  9. Opportunistically Reconstructing a Network's Failure History /

    E-Print Network [OSTI]

    Turner, Daniel Joseph

    2013-01-01

    to identify anomalies in datacenter applications [40]. Theytraffic data from a datacenter network [14]. They use thesethe failures in a datacenter environment. The techniques

  10. 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

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

    E-Print Network [OSTI]

    Singh, Viraj

    2014-05-31

    -mechanics to develop a physics based constitutive model with included damage and plasticity at micro-scale. To obtain the stress-strain behavior, appropriate micro-scale force displacement relationship is used along with the kinematic assumption and theory of stress...

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

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    at the bottom of the casting due to shrinkage driven fluid flow leads to a non-uniform solute distributionMCWASP, Modeling of Casting, Welding and Advanced Solidification Processes XI TMS (The Minerals, Aluminum alloys, Cast surfaces, Mold topography, Inverse segregation, Imperfect contact, Air-gaps, Solid

  13. Materials Science and Engineering A328 (2002) 1425 A mathematical model for the dissolution of stoichiometric

    E-Print Network [OSTI]

    Vuik, Kees

    2002-01-01

    dissolved, is re- quired to obtain a microstructure suited to undergo heavy plastic deformation. The minimum temperature at which the annealing should take place can be determined from thermodynamic analysis and industrial relevance of being able to predict the kinetics of particle dissolution, many models of various

  14. STUDY OF THE RHIC BPM SMA CONNECTOR FAILURE PROBLEM

    SciTech Connect (OSTI)

    LIAW,C.; SIKORA, R.; SCHROEDER, R.

    2007-06-25

    About 730 BPMs are mounted on the RHIC CQS and Triplet super-conducting magnets. Semi-rigid coaxial cables are used to bring the electrical signal from the BPM feedthroughs to the outside flanges. at the ambient temperature. Every year around 10 cables will lose their signals during the operation. The connection usually failed at the warm end of the cable. The problems were either the solder joint failed or the center conductor retracted out of the SMA connector. Finite element analyses were performed to understand the failure mechanism of the solder joint. The results showed that (1) The SMA center conductor can separate from the mating connector due to the thermal retraction. (2) The maximum thermal stress at the warm end solder joint can exceed the material strength of the Pb37/Sn63 solder material and (3) The magnet ramping frequency (-10 Hz), during the machine startup, can possibly resonant the coaxial cable and damage the solder joints, especially when a fracture is initiated. Test results confirmed that by using the silver bearing solder material (a higher strength material) and by crimping the cable at the locations close to the SMA connector (to prevent the center conductor from retracting) can effectively resolve the connector failure problem.

  15. Summary of failure analysis activities at Brookhaven National Laboratory

    SciTech Connect (OSTI)

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

    1996-10-01

    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.

  16. Homogenized Maxwell's Equations; a Model for Varistor Ceramics

    E-Print Network [OSTI]

    Birnir, Björn

    Homogenized Maxwell's Equations; a Model for Varistor Ceramics Bj¨orn Birnir Niklas Wellander for a semiconducting ceramic material used in devices to pro- tect electrical equipment against overvoltages are associated with two types of failures in varistor ceramics. The upper bound corresponds two thermal heating

  17. Homogenized Maxwell's Equations; a Model for Varistor Ceramics

    E-Print Network [OSTI]

    Birnir, Björn

    Homogenized Maxwell's Equations; a Model for Varistor Ceramics BjË? orn Birnir Niklas Wellander for a semiconducting ceramic material used in devices to pro­ tect electrical equipment against overvoltages are associated with two types of failures in varistor ceramics. The upper bound corresponds two thermal heating

  18. 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

    2011-12-10

    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.

  19. Mass and mixing angle patterns in the Standard Model and its material Supersymmetric Extension

    SciTech Connect (OSTI)

    Ramond, P.

    1992-01-01

    Using renormalization group techniques, we examine several interesting relations among masses and mixing angles of quarks and lepton in the Standard Model of Elementary Particle Interactions as a functionof scale. We extend the analysis to the minimal Supersymmetric Extension to determine its effect on these mass relations. For a heavy to quark, and minimal supersymmetry, most of these relations, can be made to agree at one unification scale.

  20. Model-Experimental Studies on Next-generation Li-ion Materials | Department

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

    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: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICESpecialAPPENDIX F Wetlandsof Energy Model RepairCladdings: A Statusof

  1. Model-Experimental Studies on Next-generation Li-ion Materials | Department

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

    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: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICESpecialAPPENDIX F Wetlandsof Energy Model RepairCladdings: A Statusofof

  2. Numerical modelling of sandstone uniaxial compression test using a mix-mode cohesive fracture model

    E-Print Network [OSTI]

    Gui, Yilin; Kodikara, Jayantha

    2015-01-01

    A mix-mode cohesive fracture model considering tension, compression and shear material behaviour is presented, which has wide applications to geotechnical problems. The model considers both elastic and inelastic displacements. Inelastic displacement comprises fracture and plastic displacements. The norm of inelastic displacement is used to control the fracture behaviour. Meantime, a failure function describing the fracture strength is proposed. Using the internal programming FISH, the cohesive fracture model is programmed into a hybrid distinct element algorithm as encoded in Universal Distinct Element Code (UDEC). The model is verified through uniaxial tension and direct shear tests. The developed model is then applied to model the behaviour of a uniaxial compression test on Gosford sandstone. The modelling results indicate that the proposed cohesive fracture model is capable of simulating combined failure behaviour applicable to rock.

  3. 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.

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

    E-Print Network [OSTI]

    Jimenez Martinez, Arturo

    2012-10-19

    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 ...

  5. Optimal Software Rejuvenation for Tolerating Soft Failures

    E-Print Network [OSTI]

    Telek, Miklós

    Optimal Software Rejuvenation for Tolerating Soft Failures Andr'as Pfening a;1 , Sachin Garg b;2 of software ``aging'' has come to light which causes performance of a software to degrade with time. Software of determining the optimal time to rejuvenate a server type software which experiences ``soft failures

  6. 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.

    2000-01-01

    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.

  7. Optical properties of MX chain materials: An extended Peierls-Hubbard model

    SciTech Connect (OSTI)

    Bishop, A.R.; Batistic, I.; Gammel, J.T.; Saxena, A.

    1991-01-01

    We describe theoretical modeling of both pure (MX) and mixed-halide (MX{sub x}X{prime}{sub 1-x}) halogen (X)-bridged transition metal (M) linear chain complexes in terms of an extended Peierls-Hubbard, tight-binding Hamiltonian with 3/4-filling of two-bands. Both inter- and intra-site electron-phonon coupling are included. Electronic (optical absorption), lattice dynamic (IR, Raman) and spin (ESR) signatures are obtained for the ground states, localized excited states produced by impurities, doping or photo-excitation -- excitons, polarons, bipolarons, solitons; and the edge states (which occur in mixed-halide crystals, e.g. PtCl{sub x}Br{sub 1-x}). Adiabatic molecular dynamics is used to explore photodecay channels in pure and impure systems for ground states as well as in the presence of pre-existing polaronic states. 12 refs., 3 figs., 1 tab.

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

    E-Print Network [OSTI]

    Ruj, Sushmita

    2015-01-01

    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...

  9. Coupled molecular dynamics-Monte Carlo model to study the role of chemical processes during laser ablation of polymeric materials

    SciTech Connect (OSTI)

    Prasad, Manish; Conforti, Patrick F.; Garrison, Barbara J.

    2007-08-28

    The coarse grained chemical reaction model is enhanced to build a molecular dynamics (MD) simulation framework with an embedded Monte Carlo (MC) based reaction scheme. The MC scheme utilizes predetermined reaction chemistry, energetics, and rate kinetics of materials to incorporate chemical reactions occurring in a substrate into the MD simulation. The kinetics information is utilized to set the probabilities for the types of reactions to perform based on radical survival times and reaction rates. Implementing a reaction involves changing the reactants species types which alters their interaction potentials and thus produces the required energy change. We discuss the application of this method to study the initiation of ultraviolet laser ablation in poly(methyl methacrylate). The use of this scheme enables the modeling of all possible photoexcitation pathways in the polymer. It also permits a direct study of the role of thermal, mechanical, and chemical processes that can set off ablation. We demonstrate that the role of laser induced heating, thermomechanical stresses, pressure wave formation and relaxation, and thermochemical decomposition of the polymer substrate can be investigated directly by suitably choosing the potential energy and chemical reaction energy landscape. The results highlight the usefulness of such a modeling approach by showing that various processes in polymer ablation are intricately linked leading to the transformation of the substrate and its ejection. The method, in principle, can be utilized to study systems where chemical reactions are expected to play a dominant role or interact strongly with other physical processes.

  10. Predicting crack growth in continuous-fiber composite materials

    SciTech Connect (OSTI)

    Cordes, J.A.; Yazici, R.

    1995-12-31

    Pre-notched composite lamina with unidirectional fibers were studied experimentally and using finite element analysis. Experiments were conducted on notched graphite/aluminum and glass/epoxy panels and the results were compared to a finite element method. Under remote tensile loading, cracks in the graphite/aluminum panels propagated perpendicular to the applied load without stable crack growth. In the glass/epoxy panels, crack propagation was initially stable and parallel to the fibers. A nonlinear damage zone method (DZM) was used to predict the crack growth directions, estimate damages, model stable and unstable crack growths, and predict the loads at failure. For both materials, the predicted loads at failure were within 20% of experimental loads.

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

    SciTech Connect (OSTI)

    Robert Bratton

    2010-06-01

    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.

  12. Mathematical Modelling of Weld Phenomena III, eds H. Cerjak and H. K. D. H. Bhadeshia, Institute of Materials, London, 1997, pp. 229284

    E-Print Network [OSTI]

    Cambridge, University of

    of Materials, London, 1997, pp. 229­284 Models for the Elementary Mechanical Properties of Steel Welds H. K. D. It is logical therefore to proceed to the quantitative relationships between microstructure and mechanical properties so that the variety of models can be consolidated and used directly in the design process

  13. Cascading Failure Risk Variation with Generator Dispatch and System Load Level

    E-Print Network [OSTI]

    Rezaei, Pooya

    2013-01-01

    Industry reliability rules increasingly require utilities to study and mitigate cascading failure risk in their system. Motivated by this, this paper describes how cascading failure risk, in terms of expected blackout size, varies with power system load level and pre-contingency dispatch. We used Monte Carlo sampling of random branch outages to model contingencies, and a model of cascading failure to estimate blackout sizes. The risk associated with different blackout sizes is separately estimated in order to separate small, medium, and large blackout risk. Results from N-1 secure models of the IEEE RTS case and a 2383 bus case indicate that blackout risk does not always increase with load level, particularly for large blackout risk. The results also show that risk is highly dependent on the method used for generator dispatch. Minimum cost methods of dispatch can result in larger long distance power transfers, which can increase cascading failure risk.

  14. 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.

    2013-08-15

    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.

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

    SciTech Connect (OSTI)

    Khaleel, Mohammad A.; Simonen, Fredric A.

    2009-05-01

    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.

  16. LX-17 Corner-Turning and Reactive Flow Failure

    SciTech Connect (OSTI)

    Souers, P C; Andreski, H; Cook III, C F; Garza, R; Pastrone, R; Phillips, D; Roeske, F; Vitello, P; Molitoris, J

    2004-03-11

    We have performed a series of highly-instrumented experiments examining corner-turning of detonation. A TATB booster is inset 15 mm into LX-17 (92.5% TATB, 7.5% kel-F) so that the detonation must turn a right angle around an air well. An optical pin located at the edge of the TATB gives the start time of the corner-turn. The breakout time on the side and back edges is measured with streak cameras. Three high-resolution X-ray images were taken on each experiment to examine the details of the detonation. We have concluded that the detonation cannot turn the corner and subsequently fails, but the shock wave continues to propagate in the unreacted explosive, leaving behind a dead zone. The detonation front farther out from the corner slowly turns and eventually reaches the air well edge 180{sup o} from its original direction. The dead zone is stable and persists 7.7 {micro}s after the corner-turn, although it has drifted into the original air well area. Our regular reactive flow computer models sometimes show temporary failure but they recover quickly and are unable to model the dead zones. We present a failure model that cuts off the reaction rate below certain detonation velocities and reproduces the qualitative features of the corner-turning failure.

  17. 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

    1994-11-01

    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.

  18. Low-rise shear wall failure modes

    SciTech Connect (OSTI)

    Farrar, C.R. (Los Alamos National Lab., NM (USA)); Hashimoto, P.S. (EQE Engineering, Inc., Costa Mesa, CA (USA)); Reed, J.W. (Benjamin (J.R.) and Associates, Inc., Mountain View, CA (USA))

    1991-01-01

    A summary of the data that are available concerning the structural response of low-rise shear walls is presented. This data will be used to address two failure modes associated with the shear wall structures. First, data concerning the seismic capacity of the shear walls with emphasis on excessive deformations that can cause equipment failure are examined. Second, data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary to compute the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional. 23 refs.

  19. Valve system incorporating single failure protection logic

    DOE Patents [OSTI]

    Ryan, Rodger (San Jose, CA); Timmerman, Walter J. H. (Saratoga, CA)

    1980-01-01

    A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

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

    SciTech Connect (OSTI)

    Tang, Robert Y.; Laamanen, Curtis McDonald, Nancy; LeClair, Robert J.

    2014-05-15

    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.

  1. 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.

    2014-05-01

    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.

  2. Improving service availability during link failure transients through alternate routing 

    E-Print Network [OSTI]

    Vellanki, Siridhar

    2003-01-01

    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 ...

  3. 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.

    2005-01-11

    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

  4. 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

    2005-01-01

    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.

  5. Consensus using Asynchronous Failure Detectors

    E-Print Network [OSTI]

    Lynch, Nancy

    2015-03-02

    The FLP result shows that crash-tolerant consensus is impossible to solve in asynchronous systems, and several solutions have been proposed for crash-tolerant consensus under alternative (stronger) models. One popular ...

  6. 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

  7. Impact of Motor Failures on Payback Periods 

    E-Print Network [OSTI]

    Cheek, K. F.; Pillay, P.; Dudley, K. J.

    1995-01-01

    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...

  8. Analysis of major failures in Europe's power grid

    E-Print Network [OSTI]

    Rosas-Casals, Martí

    2009-01-01

    Power grids are prone to failure. Time series of reliability measures such as total power loss or energy not supplied can give significant account of the underlying dynamical behavior of these systems, specially when the resulting probability distributions present remarkable features such as an algebraic tail, for example. In this paper, seven years (from 2002 to 2008) of Europe's transport of electricity network failure events have been analyzed and the best fit for this empirical data probability distribution is presented. With the actual span of available data and although there exists a moderate support for the power law model, the relatively small amount of events contained in the function's tail suggests that other causal factors might be significantly ruling the system's dynamics.

  9. Measuring Time to Biochemical Failure in the TROG 96.01 Trial: When Should the Clock Start Ticking?

    SciTech Connect (OSTI)

    Denham, James W.; Steigler, Allison; Kumar, Mahesh; Lamb, David S.; Joseph, David; Spry, Nigel A.; Tai, Keen-Hun; Atkinson, Chris; Turner, Sandra FRANZCR; Greer, Peter B.; Gleeson, Paul S.; D'Este, Catherine

    2009-11-15

    Purpose: We sought to determine whether short-term neoadjuvant androgen deprivation (STAD) duration influences the optimal time point from which Phoenix fail (time to biochemical failure; TTBF) should be measured. Methods and Materials: In the Trans-Tasman Radiation Oncology Group 96.01 trial, men with locally advanced prostate cancer were randomized to 3 or 6 months STAD before and during prostatic irradiation (XRT) or to XRT alone. The prognostic value of TTBF measured from the end of radiation (ERT) and randomization were compared using Cox models. Results: Between 1996 and 2000, 802 eligible patients were randomized. In 436 men with Phoenix failure, TTBF measured from randomization was a powerful predictor of prostate cancer-specific survival and marginally more accurate than TTBF measured from ERT in Cox models. Insufficient data were available to confirm that TTBF measured from testosterone recovery may also be a suitable option. Conclusions: TTBF measured from randomization (commencement of therapy) performed well in this trial dataset and will be a convenient option if this finding holds in other datasets that include long-term androgen deprivation data.

  10. 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

    2013-08-01

    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.

  11. Metallurgical failures in fossil fired boilers

    SciTech Connect (OSTI)

    French, D.N.

    1993-01-01

    This book provides a comprehensive catalog of the types of metallurgical failures common to boilers. The author uses actual case histories of boiler shutdowns, and documents the full range of causes of boiler tube failure. A blueprint is provided for cutting maintenance costs and upgrading the efficiency and reliability of any power plant operation. Individual chapters are processed separately for inclusion in the appropriate data bases.

  12. A Systems Approach to Mitigation of Project Failure Modes Athar A. Syed

    E-Print Network [OSTI]

    de Weck, Olivier L.

    execution is demonstrated through systems dynamics modeling. Thesis Advisor Olivier de Weck Associate principle to develop a general model for Project Systems using the Object- Process-Method (OPM) for systems System model, and project failure modes as well with their underlying causes are examined. The Systems

  13. Metallurgical failure analysis of a propane tank boiling liquid...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Metallurgical failure analysis of a propane tank boiling liquid expanding vapor explosion (BLEVE). Citation Details In-Document Search Title: Metallurgical failure...

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

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

    Failure Stress and Apparent Elastic Modulus of Diesel Particulate Filter Ceramics Failure Stress and Apparent Elastic Modulus of Diesel Particulate Filter Ceramics Three...

  15. 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...

  16. Interval to Biochemical Failure Highly Prognostic for Distant Metastasis and Prostate Cancer-Specific Mortality After Radiotherapy

    SciTech Connect (OSTI)

    Buyyounouski, Mark K. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)], E-mail: mark.buyyounouski@fccc.edu; Hanlon, Alexandra L.; Horwitz, Eric M.; Pollack, Alan [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)

    2008-01-01

    Purpose: Few biochemical parameters have been related to mortality. The present study examined the clinical utility of the interval to biochemical failure (IBF) as a prognostic factor for distant metastasis (DM) and prostate cancer-specific mortality (PCSM) after radiotherapy. Methods and Materials: The study group consisted of 211 T1c-T3Nx-N0M0 patients who had experienced BF among 1,174 men treated with three-dimensional conformal radiotherapy alone. Biochemical failure was defined as a post-treatment prostate-specific antigen (PSA) level of at, or greater than, the PSA nadir plus 2 ng/mL. Cox proportional hazards modeling was used to identify independent predictors of DM and PCSM on multivariate analysis. Results: An IBF of <18 months was independently predictive for DM (p = 0.008), as was a Gleason score of 7-10 (p = 0.0005), PSA nadir {>=}2 ng/mL (p = 0.04), and decreasing radiation dose (p = 0.02) on multivariate analysis, including increasing pretreatment PSA level, PSA nadir {>=}2.5 ng/mL, PSA doubling time of <3 months, and Stage T3 disease. An IBF of <18 months was the only predictor of PCSM (p = 0.0003) in the same model. The actuarial 5-year DM rate for an IBF of <18 vs. {>=}18 months was 52% vs. 20% (p < 0.0001), and the actuarial PCSM rate was 36% vs. 6%, respectively (p = 0.0001). Conclusions: The IBF is an important descriptor of the PSA kinetics after radiotherapy to identify men at high risk of clinical failure and death. A IBF of <18 months could aid in selecting men for early, aggressive salvage therapy or participation in a clinical trial.

  17. Core melt/coolant interactions: modelling. [PWR; BWR

    SciTech Connect (OSTI)

    Berman, M.; McGlaun, J.M.; Corradini, M.L.

    1983-01-01

    If there is not adequate cooling water in the core of a light-water reactor (LWR), the fission product decay heat would eventually cause the reactor fuel and cladding to melt. This could lead to slumping of the molten core materials into the lower plenum of the reactor vessel, possibly followed by failure of the vessel wall and pouring of the molten materials into the reactor cavity. When the molten core materials enter either region, there is a strong possibility of molten core contacting water. This paper focuses on analysis of recent FITS experiments, mechanistic and probabilistic model development, and the application of these models to reactor considerations.

  18. EARTH SURFACE PROCESSES AND LANDFORMS, VOL. 20, 243-EFFECTS OF SOIL MOISTURE DYNAMICS ON SLOPE FAILURE

    E-Print Network [OSTI]

    McDonnell, Jeffrey J.

    24 November 1993 ABSTRACT Field observations of shoreline conditions at Hyrum Reservoir , Uw 11 for a multiple-layered bluff en' ironment of sand and clay layers. Failure is initiated by wetting and drying of clay sediments, which produces horizontal cr;' cks within bluff material. These cracks appear to pene

  19. FAILURE OF ZIRCALOY-4 SHEET CONTAINING HYDRIDE BLISTERS O.N. Pierron1

    E-Print Network [OSTI]

    Motta, Arthur T.

    FAILURE OF ZIRCALOY-4 SHEET CONTAINING HYDRIDE BLISTERS O.N. Pierron1 , D.A. Koss1 , A.T. Motta2 , R.S. Daum3 , and K.S. Chan4 1 Dept. Materials Science and Engineering, Penn State Univ., University Park, PA 16802 2 Dept. Mechanical and Nuclear Engineering, Penn State University, University Park, PA

  20. 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

  1. Experiments on Corium Dispersion after Lower Head Failure at Moderate Pressure

    SciTech Connect (OSTI)

    BLANCHAT,THOMAS K.; GARGALLO,M.; JACOBS,G.; MEYER,L.; WILHELM,D.

    1999-09-21

    Concerning the mitigation of high pressure core melt scenarios, the design objective for future PWRS is to transfer high pressure core melt to low pressure core melt sequences, by means of pressure relief valves at the primary circuit, with such a discharge capacity to limit the pressure in the reactor coolant system to less than 20 bar. Studies have shown that in late in-vessel reflooding scenarios there may be a time window where the pressure is indeed in this range, at the moment of the reactor vessel rupture. It has to be verified that large quantities of corium released from the vessel after failure at pressures <20 bar cannot be carried out of the reactor pit, because the melt collecting and cooling concept of future PWRs would be rendered useless. Existing experiments investigated the melt dispersal phenomena in the context of the DCH resolution for existing power plants in the USA, most of them having cavities with large instrument tunnels leading into subcompartments. For such designs, breaches with small cross sections at high vessel failure pressures had been studied. However, some present and future European PWRs have an annular cavity design without a large pathway out of the cavity other than through the narrow annular gap between the RPV and the cavity wall. Therefore, an experimental program was launched, focusing on the annular cavity design and low pressure vessel failure. The first part of the program comprises two experiments which were performed with thermite melt steam and a prototypic atmosphere in the containment in a scale 1:10. The initial pressure in the RPV-model was 11 and 15 bars, and the breach was a hole at the center of the lower head with a scaled diameter of 100 cm and 40 cm, respectively. The main results were: 78% of melt mass were ejected out of the cavity with the large hole and 21% with the small hole; the maximum pressures in the model containment were 6 bar and 4 bar, respectively. In the second part of the experimental program a detailed investigation of geometry effects is being carried out. The test facility DISCO-C has been built for performing dispersion experiments with cold simulant materials in a 1/18 scale. The fluids are water or bismuth alloy instead of melt, and nitrogen or helium instead of steam.

  2. 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

    2011-09-01

    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.

  3. To be presented at ACI Fall 2009 Session on "Material Science Modeling as a Solution to Concrete Problems" (New Orleans) Virtual Testing of Concrete Transport Properties

    E-Print Network [OSTI]

    Bentz, Dale P.

    To be presented at ACI Fall 2009 Session on "Material Science Modeling as a Solution to Concrete permeability test (RCPT) that simulates the standard ASTM test method for conductivity of concrete cylinders; durability; microstructure; permeability; transport; virtual testing. #12;Biography: ACI member Dale P. Bentz

  4. Materials for defense/aerospace applications (NON-SV)

    SciTech Connect (OSTI)

    Ellis, A. R.

    2012-03-01

    Through this effort, Sandia and Lockheed Martin Aeronautics Company (LM Aero) sought to assess the feasibility of (1) applying special materials to a defense application; (2) developing a piezoelectric-based micro thermophotovoltaic (TPV) cell; and (3) building and delivering a prototype laboratory emission measurement system. This project supported the Stockpile Research & Development Program by contributing to the development of radio frequency (RF) MEMS- and optical MEMS-based components - such as switches, phase shifters, oscillators, and filters - with improved performance and reduced weight and size. Investigation of failure mechanisms and solutions helped to ensure that MEMS-based technology will meet performance requirements and long term reliability goals in the specified environments dictated by Lockheed Martin's commercial and defense applications. The objectives of this project were to (1) fabricate and test materials for military applications; (2) perform a feasibility study of a piezoelectric-based micro TPV cell; and (3) build and deliver a prototype laboratory emission measurement system. Sandia fabricated and tested properties of materials, studied options for manufacturing scale-up, and delivered a prototype IR Emissometer. LM Aero provided material requirements and designs. Both participated in the investigation of attachment methods and environmental effects on material performance, a feasibility study of piezoelectric TPV cells, an investigation and development of new approaches to implement the required material functionality, and analysis and validation of material performance physics, numerical models, and experimental metrology.

  5. Material Misfits

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

    Issues submit Material Misfits How well nanocomposite materials align at their interfaces determines what properties they have, opening broad new avenues of materials-science...

  6. Mining Simulation Metrics for Failure Triage in Regression Testing

    E-Print Network [OSTI]

    Veneris, Andreas

    are grouped by applying data-mining clustering algorithms. Fi- nally, the generated failure clustersMining Simulation Metrics for Failure Triage in Regression Testing Zissis Poulos1 , Andreas Veneris of failures can be exposed. These failures need to be properly grouped and distributed among engineers

  7. 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

  8. 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

  9. 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

  10. A Report on Simulation-Driven Reliability and Failure Analysis of Large-Scale Storage Systems

    SciTech Connect (OSTI)

    Wan, Lipeng; Wang, Feiyi; Oral, H. Sarp; Vazhkudai, Sudharshan S.; Cao, Qing

    2014-11-01

    High-performance computing (HPC) storage systems provide data availability and reliability using various hardware and software fault tolerance techniques. Usually, reliability and availability are calculated at the subsystem or component level using limited metrics such as, mean time to failure (MTTF) or mean time to data loss (MTTDL). This often means settling on simple and disconnected failure models (such as exponential failure rate) to achieve tractable and close-formed solutions. However, such models have been shown to be insufficient in assessing end-to-end storage system reliability and availability. We propose a generic simulation framework aimed at analyzing the reliability and availability of storage systems at scale, and investigating what-if scenarios. The framework is designed for an end-to-end storage system, accommodating the various components and subsystems, their interconnections, failure patterns and propagation, and performs dependency analysis to capture a wide-range of failure cases. We evaluate the framework against a large-scale storage system that is in production and analyze its failure projections toward and beyond the end of lifecycle. We also examine the potential operational impact by studying how different types of components affect the overall system reliability and availability, and present the preliminary results

  11. Can complexity decrease in Congestive Heart failure?

    E-Print Network [OSTI]

    Mukherjee, Sayan; Banerjee, Santo; Ariffin, M R K; Rondoni, Lamberto; Bhattacharya, D K

    2015-01-01

    The complexity of a signal can be measured by the Recurrence period density entropy (RPDE) from the reconstructed phase space. We have chosen a window based RPDE method for the classification of signals, as RPDE is an average entropic measure of the whole phase space. We have observed the changes in the complexity in cardiac signals of normal healthy person (NHP) and congestive heart failure patients (CHFP). The results show that the cardiac dynamics of a healthy subject is more complex and random compare to the same for a heart failure patient, whose dynamics is more deterministic. We have constructed a general threshold to distinguish the border line between a healthy and a congestive heart failure dynamics. The results may be useful for wide range for physiological and biomedical analysis.

  12. Can complexity decrease in Congestive Heart failure?

    E-Print Network [OSTI]

    Sayan Mukherjee; Sanjay Kumar Palit; Santo Banerjee; M. R. K. Ariffin; Lamberto Rondoni; D. K. Bhattacharya

    2015-08-06

    The complexity of a signal can be measured by the Recurrence period density entropy (RPDE) from the reconstructed phase space. We have chosen a window based RPDE method for the classification of signals, as RPDE is an average entropic measure of the whole phase space. We have observed the changes in the complexity in cardiac signals of normal healthy person (NHP) and congestive heart failure patients (CHFP). The results show that the cardiac dynamics of a healthy subject is more complex and random compare to the same for a heart failure patient, whose dynamics is more deterministic. We have constructed a general threshold to distinguish the border line between a healthy and a congestive heart failure dynamics. The results may be useful for wide range for physiological and biomedical analysis.

  13. Generic failure mechanisms in adhesive bonds

    E-Print Network [OSTI]

    Hass, Philipp; Niemz, Peter

    2015-01-01

    The failure of adhesive bondlines has been studied at the microscopic level via tensile tests. Stable crack propagation could be generated by means of samples with improved geometry, which made in-situ observations possible. The interaction of cracks with adhesive bondlines under various angles to the crack propagation was the focus of this study as well as the respective loading situations for the adhesives UF, PUR, and PVAc, which have distinctly different mechanical behaviors. It is shown how adhesive properties influence the occurrence of certain failure mechanisms and determine their appearance and order of magnitude. With the observed failure mechanisms, it becomes possible to predict the propagation path of a crack through the specimen.

  14. 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

  15. Polymer Filler Aging and Failure Studied by Lateral Force Microscopy

    SciTech Connect (OSTI)

    Ratto, T; Saab, A P

    2009-05-27

    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.

  16. Three-dimensional geomechanical simulation of reservoir compaction and implications for well failures in the Belridge diatomite

    SciTech Connect (OSTI)

    Fredrich, J.T. [SPE, Richardson, TX (United States); Argueello, J.G.; Thorne, B.J.; Wawersik, W.R. [SPE, Richardson, TX (United States)]|[Sandia National Lab., Albuquerque, NM (United States)] [and others

    1996-11-01

    This paper describes an integrated geomechanics analysis of well casing damage induced by compaction of the diatomite reservoir at the Belridge Field, California. Historical data from the five field operators were compiled and analyzed to determine correlations between production, injection, subsidence, and well failures. The results of this analysis were used to develop a three-dimensional geomechanical model of South Belridge, Section 33 to examine the diatomite reservoir and overburden response to production and injection at the interwell scale and to evaluate potential well failure mechanisms. The time-dependent reservoir pressure field was derived from a three-dimensional finite difference reservoir simulation and used as input to three-dimensional non-linear finite element geomechanical simulations. The reservoir simulation included -200 wells and covered 18 years of production and injection. The geomechanical simulation contained 437,100 nodes and 374,130 elements with the overburden and reservoir discretized into 13 layers with independent material properties. The results reveal the evolution of the subsurface stress and displacement fields with production and injection and suggest strategies for reducing the occurrence of well casing damage.

  17. Materials of Gasification

    SciTech Connect (OSTI)

    2005-09-15

    The objective of this project was to accumulate and establish a database of construction materials, coatings, refractory liners, and transitional materials that are appropriate for the hardware and scale-up facilities for atmospheric biomass and coal gasification processes. Cost, fabricability, survivability, contamination, modes of corrosion, failure modes, operational temperatures, strength, and compatibility are all areas of materials science for which relevant data would be appropriate. The goal will be an established expertise of materials for the fossil energy area within WRI. This would be an effort to narrow down the overwhelming array of materials information sources to the relevant set which provides current and accurate data for materials selection for fossil fuels processing plant. A significant amount of reference material on materials has been located, examined and compiled. The report that describes these resources is well under way. The reference material is in many forms including texts, periodicals, websites, software and expert systems. The most important part of the labor is to refine the vast array of available resources to information appropriate in content, size and reliability for the tasks conducted by WRI and its clients within the energy field. A significant has been made to collate and capture the best and most up to date references. The resources of the University of Wyoming have been used extensively as a local and assessable location of information. As such, the distribution of materials within the UW library has been added as a portion of the growing document. Literature from recent journals has been combed for all pertinent references to high temperature energy based applications. Several software packages have been examined for relevance and usefulness towards applications in coal gasification and coal fired plant. Collation of the many located resources has been ongoing. Some web-based resources have been examined.

  18. 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

    2011-01-01

    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,

  19. Operating Experience Level 3, Update to Requalification Test Failure of Certain High Efficiency Particulate Air (HEPA) Filters

    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) Filters models manufactured by Flanders Corporation.

  20. Effect of Component Failures on Economics of Distributed Photovoltaic Systems

    SciTech Connect (OSTI)

    Lubin, Barry T.

    2012-02-02

    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.

  1. 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...

  2. Survey on Failure Modes and Failure Mechanisms in Digital Components and Systems

    SciTech Connect (OSTI)

    Cetiner, Mustafa Sacit; Korsah, Kofi; Muhlheim, Michael David

    2009-01-01

    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.

  3. 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)

    2014-10-01

    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.

  4. Photomultiplier tube failure under hydrostatic pressure in future neutrino detectors

    SciTech Connect (OSTI)

    Chambliss, K.; Diwan, M.; Simos, N.; Sundaram, S. K.

    2014-10-09

    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.

  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.

    2014-10-09

    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. Modeling a fluid to solid phase transition in snow weak-layers. Application to slab avalanche release

    E-Print Network [OSTI]

    Francois Louchet

    2015-04-07

    Snow slab avalanche release usually results from failure of weak layers made of loose ice crystals. In previous field experiments, we evidenced for the first time an interesting stress-driven transition in the weak layer between a granular fluid and a solid phase. We propose here an original model involving the kinetics of ice grains bonds failure and reconstruction. The model evidences a sudden transition between two drastically different types of weak layer behaviors. It accounts for the characteristics of both the studied fluid-solid transition and for slab avalanche release observations. It may possibly apply to a number of other granular materials.

  7. A Study to Verify the Material Surface Concept of Water Table by Examining Analytical and Numerical Models

    E-Print Network [OSTI]

    Dadi, Sireesh Kumar

    2011-10-21

    : the Neuman model, which assumes instantaneous drainage from the unsaturated zone; the Moench model, which considered gradual drainage from the unsaturated zone using a series of exponential terms in the water table boundary condition; and the Mathias...

  8. 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.

    1998-08-01

    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.

  9. Covetic Materials

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

    Can re-melt, dilute, alloy... Fabrication of Covetic Materials - Nanocarbon Infusion 3 4 Technical Approach Unusual Characteristics of Covetic Materials ("covalent" &...

  10. Failure of silicon nitride under uniaxial compression at high temperature

    E-Print Network [OSTI]

    Gei, Massimiliano

    nitride cylinders have been investigated under uniaxial compression at 1200 °C in air. Samples has been carried out in order to de- scribe the onset of the specific failure mode. The first failure

  11. Gearbox Typical Failure Modes, Detection, and Mitigation Methods (Presentation)

    SciTech Connect (OSTI)

    Sheng, S.

    2014-01-01

    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. Users May Now Clear Their Own Login Failures

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

    Users May Now Clear Their Own Login Failures Users May Now Clear Their Own Login Failures May 16, 2013 by Francesca Verdier (0 Comments) Users may now clear their own login...

  13. Quality of Service of Crash-Recovery Failure Detectors 

    E-Print Network [OSTI]

    Ma, Tiejun

    2007-11-07

    This thesis presents the results of an investigation into the failure detection problem. We consider the specific case of the Quality of Service (QoS) of crash failure detection. In contrast to previous work, we address ...

  14. Timing analysis of PWR fuel pin failures

    SciTech Connect (OSTI)

    Jones, K.R.; Wade, N.L.; Katsma, K.R.; Siefken, L.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Straka, M. (Halliburton NUS, Idaho Falls, ID (United States))

    1992-09-01

    This report discusses research conducted to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B W) design (Oconee) and a Westinghouse (W) four-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin burnup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using the following codes: FRAPCON-2, for the calculation of steady-state fuel behavior; SCDAP/RELAP5/MOD3 and TRACPF1/MOD1, for the calculation of the transient thermal-hydraulic conditions in the reactor system; and FRAP-T6, for the calculation of transient fuel behavior. In addition to the calculation of fuel pin failure timing, this analysis provides a comparison of the predicted results of SCDAP/RELAP5/MOD3 and TRAC-PF1/MOD1 for large-break LOCA analysis. Using SCDAP/RELAP5/MOD3 thermal-hydraulic data, the shortest time intervals calculated between initiation of containment isolation and fuel pin failure are 10.4 seconds and 19.1 seconds for the B W and W plants, respectively. Using data generated by TRAC-PF1/MOD1, the shortest intervals are 10.3 seconds and 29.1 seconds for the B W and W plants, respectively. These intervals are for a double-ended, offset-shear, cold leg break, using the technical specification maximum peaking factor and applied to fuel with maximum design burnup. Using peaking factors commensurate with actual burnups would result in longer intervals for both reactor designs. This document provides appendices K and L of this report which provide plots for the timing analysis of PWR fuel pin failures for Oconee and Seabrook respectively.

  15. 2008 Midwest Levee Failure: Erosion Studies 

    E-Print Network [OSTI]

    Bernhardt, Michelle Lee

    2011-02-22

    of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Jean-Louis Briaud Committee Members, Giovanna Biscontin Russell W. Jessup Head of Department, Mark Burris December 2009 Major Subject: Civil Engineering iii... ABSTRACT 2008 Midwest Levee Failures: Erosion Studies. (December 2009) Michelle Lee Bernhardt, B.S., Texas A&M University Chair of Advisory Committee: Dr. Jean-Louis Briaud The United States contains an estimated 100,000 miles (160000 km...

  16. A Latent Model to Detect Multiple Spatial Clusters with Application in a Mobile Sensor Network for Surveillance of Nuclear Materials

    E-Print Network [OSTI]

    devastating, and the global proliferation of nuclear weapon technology has made the threat increasingly serious. The U.S. government has made significant efforts to curb nuclear proliferation. In spite of many for Surveillance of Nuclear Materials Jerry Cheng, Minge Xie, Rong Chen and Fred Roberts1 Abstract Nuclear attacks

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

    E-Print Network [OSTI]

    Morton, David

    are transparent to the smuggler, and are made under an uncertain threat scenario, which specifies the smuggler by profit and a perceived demand on the illegal market. Other smuggling attempts were apparently motivated the smuggling of nuclear material. Well-designed deployment can significantly improve system performance

  18. Soft Failures in Large Datacenters Sriram Sankar and Sudhanva Gurumurthi

    E-Print Network [OSTI]

    Gurumurthi, Sudhanva

    Soft Failures in Large Datacenters Sriram Sankar and Sudhanva Gurumurthi Abstract-- A major problem in managing large-scale datacenters is diagnosing and fixing machine failures. Most large datacenter an important issue at large datacenters with minimum human intervention. Soft failures in the datacenter do

  19. Failure Time Analysis for LMS Algorithms Adel A. Zerai

    E-Print Network [OSTI]

    Bucklew, James Antonio

    Failure Time Analysis for LMS Algorithms Adel A. Zerai Electronics Engineering Technology) analysis of the LMS adaptive algorithms (#12;lters). Such analysis is extremely important when failure of time (a clump of large errors). We use Poisson approximation to study excursions (failure) of the LMS

  20. 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

  1. 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

  2. BWR containment failure analysis during degraded-core accidents

    SciTech Connect (OSTI)

    Yue, D.D.

    1982-06-06

    This paper presents a containment failure mode analysis during a spectrum of postulated degraded core accident sequences in a typical 1000-MW(e) boiling water reactor (BWR) with a Mark-I wetwell containment. Overtemperature failure of containment electric penetration assemblies (CEPAs) has been found to be the major failure mode during such accidents.

  3. Probabilistic Failure Detection for Efficient Distributed Storage Maintenance* , Zhi Yang*

    E-Print Network [OSTI]

    Almeroth, Kevin C.

    avail- ability. Node failures can be transient or permanent. While the system must generate new replicasProbabilistic Failure Detection for Efficient Distributed Storage Maintenance* Jing Tian* , Zhi@cs.ucsb.edu Abstract Distributed storage systems often use data replica- tion to mask failures and guarantee high data

  4. Algorithm-Based Fault Tolerance for Fail-Stop Failures

    E-Print Network [OSTI]

    Dongarra, Jack

    after failures, the next generation high performance computing applications need to be able to continue1 Algorithm-Based Fault Tolerance for Fail-Stop Failures Zizhong Chen and Jack Dongarra Abstract Fail-stop failures in distributed environments are often tolerated by checkpointing or message logging

  5. PDC IC WELD FAILURE EVALUATION AND RESOLUTION

    SciTech Connect (OSTI)

    Korinko, P.; Howard, S.; Maxwell, D.; Fiscus, J.

    2012-04-16

    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

  6. Tube fragmentation of multiple materials.

    SciTech Connect (OSTI)

    Thornhill, Tom Finley, III (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Chhabildas, Lalit Chandra

    2003-07-01

    In the current study we are developing an experimental fracture material property test method specific to dynamic fragmentation. This test method allows the study of fracture fragmentation in a reproducible laboratory environment under well-controlled loading conditions. Motion and fragmentation of the specimen are diagnosed using framing camera, VISAR and soft recovery methods. Fragmentation properties of several steels, nitinol, tungsten alloy, copper, aluminum, and titanium have been obtained to date. The values for fragmentation toughness, and failure threshold will be reported, as well as effects in these values as the material strain-rate is varied through changes in wall thickness and impact conditions.

  7. Tube Fragmentation of Multiple Materials

    SciTech Connect (OSTI)

    Thornhill, T. F. [Ktech Corporation, Suite 400, 2201 Buena Vista SE, Albuquerque, NM 87106-4265 (United States); Chhabildas, L. C.; Vogler, T. J. [Sandia National Laboratories, Department 1647, PO Box 5800, Albuquerque, NM 87185 (United States)

    2006-07-28

    In the current study we are developing an experimental fracture material property test method specific to dynamic fragmentation. This test method allows the study of fracture fragmentation in a reproducible laboratory environment under well-controlled loading conditions. Motion and fragmentation of the specimen are diagnosed using framing camera, VISAR and soft recovery methods. Fragmentation properties of several steels, nitinol, tungsten alloy, copper, aluminum, and titanium have been obtained to date. The values for fragmentation toughness, and failure threshold will be reported, as well as effects in these values as the material strain-rate is varied through changes in wall thickness and impact conditions.

  8. material protection

    National Nuclear Security Administration (NNSA)

    %2A en Office of Weapons Material Protection http:www.nnsa.energy.govaboutusourprogramsnonproliferationprogramofficesinternationalmaterialprotectionandcooperation-1

  9. Critical Materials:

    Office of Environmental Management (EM)

    Extraction Separation Processes for Critical Materials in 30- 21 Stage Test Facility (Bruce Moyer) ......

  10. Materials Scientist

    Broader source: Energy.gov [DOE]

    Alternate Title(s):Materials Research Engineer; Metallurgical/Chemical Engineer; Product Development Manager;

  11. Microfracturing, damage, and failure of brittle granites and Ze'ev Reches

    E-Print Network [OSTI]

    Ze'ev, Reches

    Microfracturing, damage, and failure of brittle granites Oded Katz1 and Ze'ev Reches Institute; accepted 17 October 2003; published 20 January 2004. [1] The evolution of stress-induced damage the damage intensity in two methods and directly compare model predictions and actual damage. The 14 samples

  12. Oxygen-induced bi-modal failure phenomenon in SiOx-based resistive switching memory

    E-Print Network [OSTI]

    Yu, Edward T.

    -pJ energy consumption,3 low cost, and robust reliability.4 A simple process with conventional CMOS Carlo simulation using bi-modal statistics to enable feature distribution modeling of failure modes are the critical requirements for commercial ReRAM products. Silicon oxide (SiOx) has been used as gate dielectrics

  13. 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

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

    E-Print Network [OSTI]

    , Ames, IA 50011-1040, USA {jpathak, jiangy, honavar, jdm}@iastate.edu Abstract Cost-effective equipment substation equipment condition data collected from distributed data resources, some of which may be local to the substation, to develop Hidden Markov Models (HMMs) which transform the condition data into failure

  15. JAP-00590-2004 Mechanics, nonlinearity, and failure strength of lung tissue in a mouse

    E-Print Network [OSTI]

    Lutchen, Kenneth

    JAP-00590-2004 Mechanics, nonlinearity, and failure strength of lung tissue in a mouse model% higher in the PPE-treated group (P lung hydroxyproline content, which represents remodeling may play a significant role in all aspects of lung functional changes leading to progressive

  16. On the failure of graphene devices by Joule heating under current stressing conditions

    E-Print Network [OSTI]

    Durkan, Colm; Xiao, Zhuocong

    2015-01-01

    The behaviour of single layer graphene sections under current-stressing conditions is presented. Graphene devices are stressed to the point of failure and it is seen that they exhibit Joule heating. Using a simple 1-D model for heat generation, we...

  17. Dynamic failure prediction of cross-rolled beryllium sheets subjected to vibration loads 

    E-Print Network [OSTI]

    Serna, Oscar R.

    1996-01-01

    information. Specimen length and width dimensions vary from I 1 4.3 x 25.4 mm (4.5 x 1.0 in.) to 114.3 x 114.3 mm (4.5 x 4.5 in.). Frequencies of excitation ranged from 71 Hz to 96 Hz. Tsai-Wu failure models for regular annealed glass and cross...

  18. Materials Department Annual Report 1992

    E-Print Network [OSTI]

    Materials Technology 37 4.1 Manufacturing Processes for Advanced Composites 37 4.2 Polymer Antioxidants 38 4-2840 ISSN 0906-3242 Grafisk Service, Riso, 1993 #12;Contents ^n Introduction 5 ^ y Materials Science 13 2.1 Modelling within Materials Science 13 2.2 Micromechanical Modelling /> 2.3 Scale-Effects in C u V IT 2A

  19. 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

  20. Estimating Overall Risk of Dam Failure: Practical Considerations in Combining Failure Probabilities ANCOLD 2003 Risk Workshop Page 1

    E-Print Network [OSTI]

    Bowles, David S.

    Estimating Overall Risk of Dam Failure: Practical Considerations in Combining Failure Probabilities ANCOLD 2003 Risk Workshop Page 1 ESTIMATING OVERALL RISK OF DAM FAILURE: PRACTICAL CONSIDERATIONS With the move to a risk based approach to dam safety there has been a concomitant focus on estimating

  1. Absolute nuclear material assay

    DOE Patents [OSTI]

    Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

    2012-05-15

    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.

  2. Absolute nuclear material assay

    DOE Patents [OSTI]

    Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

    2010-07-13

    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.

  3. 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

    2013-12-01

    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.

  4. Timing analysis of PWR fuel pin failures

    SciTech Connect (OSTI)

    Jones, K.R.; Wade, N.L.; Katsma, K.R.; Siefken, L.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Straka, M. (Halliburton NUS, Idaho Falls, ID (United States))

    1992-09-01

    Research has been conducted to develop and demonstrate a methodology for calculation of the time interval between receipt of the containment isolation signals and the first fuel pin failure for loss-of-coolant accidents (LOCAs). Demonstration calculations were performed for a Babcock and Wilcox (B W) design (Oconee) and a Westinghouse (W) four-loop design (Seabrook). Sensitivity studies were performed to assess the impacts of fuel pin bumup, axial peaking factor, break size, emergency core cooling system availability, and main coolant pump trip on these times. The analysis was performed using the following codes: FRAPCON-2, for the calculation of steady-state fuel behavior; SCDAP/RELAP5/MOD3 and TRACPF1/MOD1, for the calculation of the transient thermal-hydraulic conditions in the reactor system; and FRAP-T6, for the calculation of transient fuel behavior. In addition to the calculation of fuel pin failure timing, this analysis provides a comparison of the predicted results of SCDAP/RELAP5/MOD3 and TRAC-PFL/MOD1 for large-break LOCA analysis. Using SCDAP/RELAP5/MOD3 thermal-hydraulic data, the shortest time intervals calculated between initiation of containment isolation and fuel pin failure are 10.4 seconds and 19.1 seconds for the B W and W plants, respectively. Using data generated by TRAC-PF1/MOD1, the shortest intervals are 10.3 seconds and 29.1 seconds for the B W and W plants, respectively. These intervals are for a double-ended, offset-shear, cold leg break, using the technical specification maximum peaking factor and applied to fuel with maximum design bumup. Using peaking factors commensurate widi actual bumups would result in longer intervals for both reactor designs. This document also contains appendices A through J of this report.

  5. Supplementary Materials to "Adaptive Output-Feedback Control for Relative Degree Two Systems Based on Closed-Loop Reference Models"

    E-Print Network [OSTI]

    Qu, Zheng

    2015-09-14

    Abstract--- In this paper, a new adaptive output-feedback controller for multi-input-multi-output (MIMO) linear plant models with relative degree two is developed. The adaptive controller includes a baseline design based ...

  6. 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

    2011-01-01

    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.

  7. Robustness of scale-free networks to cascading failures induced by fluctuating loads

    E-Print Network [OSTI]

    Mizutaka, Shogo

    2015-01-01

    Taking into account the fact that overload failures in real-world functional networks are usually caused by extreme values of temporally fluctuating loads that exceed the allowable range, we study the robustness of scale-free networks against cascading overload failures induced by fluctuating loads. In our model, loads are described by random walkers moving on a network and a node fails when the number of walkers on the node is beyond the node capacity. Our results obtained by using the generating function method shows that scale-free networks are more robust against cascading overload failures than Erd\\H{o}s-R\\'enyi random graphs with homogeneous degree distributions. This conclusion is contrary to that predicted by previous works which neglect the effect of fluctuations of loads.

  8. Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation

    SciTech Connect (OSTI)

    Abercrombie, Robert K; Schlicher, Bob G; Sheldon, Frederick T

    2014-01-01

    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.

  9. Reduce Steam Trap Failures at Chambers Works 

    E-Print Network [OSTI]

    Kouba, C.

    2010-01-01

    Failures at Chambers Works GB/BB Name: Cyndi Kouba Mentor/MBB: Andrew Degraff Team Members Michael Crowley(Site Energy Lead), (Charlie) Flanigan (Aramids-maintenance), Ben Snyder (Aramids-ATO), Michael Scruggs (Central Maintenance Mechanic), Rick... 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: Chambers Works site Voice...

  10. 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

    2010-09-01

    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.

  11. 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

    2012-05-30

    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.

  12. Cascade Failures from Distributed Generation in Power Grids

    E-Print Network [OSTI]

    Scala, Antonio; Scoglio, Caterina

    2012-01-01

    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. Materials Science

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

    Database (TPMD) Aerospace Structural Metals Database (ASMD) Damage Tolerant Design Handbook (DTDH) Microelectronics Packaging Materials Database (MPMD) Structural Alloys...

  14. Bladder Cancer Patterns of Pelvic Failure: Implications for Adjuvant Radiation Therapy

    SciTech Connect (OSTI)

    Baumann, Brian C.; Guzzo, Thomas J.; He Jiwei; Vaughn, David J.; Keefe, Stephen M.; Vapiwala, Neha; Deville, Curtiland; Bekelman, Justin E.; Tucker, Kai; Hwang, Wei-Ting; Malkowicz, S. Bruce; Christodouleas, John P.

    2013-02-01

    Purpose: Local-regional failures (LFs) after cystectomy with or without chemotherapy are common in locally advanced disease. Adjuvant radiation therapy (RT) could reduce LFs, but toxicity has discouraged its use. Modern RT techniques with improved normal tissue sparing have rekindled interest but require knowledge of pelvic failure patterns to design treatment volumes. Methods and Materials: Five-year LF rates after radical cystectomy plus pelvic node dissection with or without chemotherapy were determined for 8 pelvic sites among 442 urothelial bladder carcinoma patients. The impact of pathologic stage, margin status, nodal involvement, and extent of node dissection on failure patterns was assessed using competing risk analysis. We calculated the percentage of patients whose sites of LF would have been completely encompassed within various hypothetical clinical target volumes (CTVs) for postoperative radiation. Results: Compared with stage {<=}pT2, stage {>=}pT3 patients had higher 5-year LF rates in virtually all pelvic sites. Among stage {>=}pT3 patients, margin status significantly altered the failure pattern whereas extent of node dissection and nodal positivity did not. In stage {>=}pT3 patients with negative margins, failure occurred predominantly in the iliac/obturator nodes and uncommonly in the cystectomy bed and/or presacral nodes. Of these patients in whom failure subsequently occurred, 76% would have had all LF sites encompassed within CTVs covering only the iliac/obturator nodes. In stage {>=}pT3 with positive margins, cystectomy bed and/or presacral nodal failures increased significantly. Only 57% of such patients had all LF sites within CTVs limited to the iliac/obturator nodes, but including the cystectomy bed and presacral nodes in the CTV when margins were positive increased the percentage of LFs encompassed to 91%. Conclusions: Patterns of failure within the pelvis are summarized to facilitate design of adjuvant RT protocols. These data suggest that RT should target at least the iliac/obturator nodes in stage {>=}pT3 with negative margins; coverage of the presacral nodes and cystectomy bed may be necessary for stage {>=}pT3 with positive margins.

  15. Please cite as: P. W. Dondl, K. Hormann, and J. Zimmer. Modeling transformation paths of multiphase materials: The triple point of zirconia. Physical Review B, 79(10):104114, March 2009.

    E-Print Network [OSTI]

    Hormann, Kai

    materials: The triple point of zirconia. Physical Review B, 79(10):104114, March 2009. Modelling transformation paths of multiphase materials: The triple point of zirconia Patrick W. Dondl Max. The method is applied to the triple point of zirconia, where tetragonal, orthorhombic (ortho

  16. FailureSense: Detecting Sensor Failure using Electrical Appliances in the Home

    E-Print Network [OSTI]

    Stankovic, John A.

    in smart homes for various applications, including home health care, energy management, and se- curity@cs.virginia.edu Abstract--With the proliferation of inexpensive sensors, sensors are increasingly being used in smart homes risk of various types of sensor failure. Motivated by real examples, we develop new schemes to detect

  17. Risk Analysis of the Space Shuttle: Pre-Challenger Bayeisan Prediction of Failure

    SciTech Connect (OSTI)

    Dana L. Kelly

    2008-02-01

    Dalal et al performed a statistical analysis of field and nozzle O-ring data collected prior to the ill-fated launch of the Challenger in January 1986. The purpose of their analysis was to show how statistical analysis could be used to provide information to decisionmakers prior to the launch, information that could have been expected to lead to a decision to abort the launch due to the low temperatures (~30o F.) present at the launch pad on the morning of the scheduled launch. Dalal et al. performed a frequentist analysis of the O-ring data, and found that a logistic regression model provided a relatively good fit to the past data. In the second portion of their paper, Dalal et al. propagated parameter uncertainties through the fitted logistic regression model in order to estimate the probability of shuttle failure due to O-ring failure at the estimated launch temperature of ~30o F. Because their analysis was frequentist in nature, probability distributions representing epistemic uncertainty in the input parameters were not available, and the authors had to resort to an approximate approach based on bootstrap confidence intervals. In this paper, we will re-evaluate the analyses of Dalal et al. from a Bayesian perspective. Markov chain Monte Carlo (MCMC) sampling will be used to sample from the joint posterior distribution of the model parameters, and to sample from the posterior predictive distributions at the estimated launch temperature, a temperature that had not been observed in prior launches of the space shuttle. Uncertainties, which are represented by probability distributions in the Bayesian approach, are propagated through the model to obtain a probability distribution for O-ring failure, and subsequently for shuttle failure as a result of O-ring failure. No approximations are required in the Bayesian approach and the resulting distributions can be input to a decision analysis to obtain expected utility for the decision to launch.

  18. 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

  19. METALLURGICAL AND MATERIALS TRANSACTIONS B VOLUME 28B, DECEMBER 1997--1165 Modeling of Solidification of Metal-Matrix Particulate

    E-Print Network [OSTI]

    Beckermann, Christoph

    of Solidification of Metal-Matrix Particulate Composites with Convection R.J. FELLER and C. BECKERMANN A multiphase model for the alloy solidification of metal-matrix particulate composites with convec- tion is developed settling prior to entrap- ment results in large denuded and packed zones in the casting. Fluid flow

  20. Percentage of Biopsy Cores Positive for Malignancy and Biochemical Failure Following Prostate Cancer Radiotherapy in 3,264 Men: Statistical Significance Without Predictive Performance

    SciTech Connect (OSTI)

    Williams, Scott G. [Peter MacCallum Cancer Centre and University of Melbourne, Melbourne (Australia)], E-mail: scott.williams@petermac.org; Buyyounouski, Mark K. [Fox Chase Cancer Center, Philadelphia, PA (United States); Pickles, Tom [British Columbia Cancer Agency, Vancouver, BC (Canada); Kestin, Larry; Martinez, Alvaro [William Beaumont Hospital, Royal Oak, MI (United States); Hanlon, Alexandra L. [Fox Chase Cancer Center, Philadelphia, PA (United States); Duchesne, Gillian M. [Peter MacCallum Cancer Centre and University of Melbourne, Melbourne (Australia)

    2008-03-15

    Purpose: To define and incorporate the impact of the percentage of positive biopsy cores (PPC) into a predictive model of prostate cancer radiotherapy biochemical outcome. Methods and Materials: The data of 3264 men with clinically localized prostate cancer treated with external beam radiotherapy at four institutions were retrospectively analyzed. Standard prognostic and treatment factors plus the number of biopsy cores collected and the number positive for malignancy by transrectal ultrasound-guided biopsy were available. The primary endpoint was biochemical failure (bF, Phoenix definition). Multivariate proportional hazards analyses were performed and expressed as a nomogram and the model's predictive ability assessed using the concordance index (c-index). Results: The cohort consisted of 21% low-, 51% intermediate-, and 28% high-risk cancer patients, and 30% had androgen deprivation with radiotherapy. The median PPC was 50% (interquartile range [IQR] 29-67%), and median follow-up was 51 months (IQR 29-71 months). Percentage of positive biopsy cores displayed an independent association with the risk of bF (p = 0.01), as did age, prostate-specific antigen value, Gleason score, clinical stage, androgen deprivation duration, and radiotherapy dose (p < 0.001 for all). Including PPC increased the c-index from 0.72 to 0.73 in the overall model. The influence of PPC varied significantly with radiotherapy dose and clinical stage (p = 0.02 for both interactions), with doses <66 Gy and palpable tumors showing the strongest relationship between PPC and bF. Intermediate-risk patients were poorly discriminated regardless of PPC inclusion (c-index 0.65 for both models). Conclusions: Outcome models incorporating PPC show only minor additional ability to predict biochemical failure beyond those containing standard prognostic factors.

  1. Fluid-driven deformation of a soft granular material

    E-Print Network [OSTI]

    Christopher W. MacMinn; Eric R. Dufresne; John S. Wettlaufer

    2015-02-24

    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.

  2. Learning Geo-Temporal Non-Stationary Failure and Recovery of Power Distribution

    E-Print Network [OSTI]

    Wei, Yun; Galvan, Floyd; Couvillon, Stephen; Orellana, George; Momoh, James

    2013-01-01

    Smart energy grid is an emerging area for new applications of machine learning in a non-stationary environment. Such a non-stationary environment emerges when large-scale failures occur at power distribution networks due to external disturbances such as hurricanes and severe storms. Power distribution networks lie at the edge of the grid, and are especially vulnerable to external disruptions. Quantifiable approaches are lacking and needed to learn non-stationary behaviors of large-scale failure and recovery of power distribution. This work studies such non-stationary behaviors in three aspects. First, a novel formulation is derived for an entire life cycle of large-scale failure and recovery of power distribution. Second, spatial-temporal models of failure and recovery of power distribution are developed as geo-location based multivariate non-stationary GI(t)/G(t)/Infinity queues. Third, the non-stationary spatial-temporal models identify a small number of parameters to be learned. Learning is applied to two ...

  3. Material-based design computation

    E-Print Network [OSTI]

    Oxman, Neri

    2010-01-01

    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 ...

  4. Link failure detection in a parallel computer

    DOE Patents [OSTI]

    Archer, Charles J. (Rochester, MN); Blocksome, Michael A. (Rochester, MN); Megerian, Mark G. (Rochester, MN); Smith, Brian E. (Rochester, MN)

    2010-11-09

    Methods, apparatus, and products are disclosed for link failure detection in a parallel computer including compute nodes connected in a rectangular mesh network, each pair of adjacent compute nodes in the rectangular mesh network connected together using a pair of links, that includes: assigning each compute node to either a first group or a second group such that adjacent compute nodes in the rectangular mesh network are assigned to different groups; sending, by each of the compute nodes assigned to the first group, a first test message to each adjacent compute node assigned to the second group; determining, by each of the compute nodes assigned to the second group, whether the first test message was received from each adjacent compute node assigned to the first group; and notifying a user, by each of the compute nodes assigned to the second group, whether the first test message was received.

  5. Failure Forewarning in NPP Equipment NERI2000-109 Final Project Report

    SciTech Connect (OSTI)

    Hively, LM

    2004-03-26

    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.

  6. Sandia Energy - Failure Mode and Effect Analysis (FMEA) Tutorial

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

    and Effect Analysis (FMEA) Tutorial Home Stationary Power Energy Conversion Efficiency Solar Energy Photovoltaics PV Systems Reliability Tutorial on FMEA Process Failure Mode...

  7. The Sandia MEMS Passive Shock Sensor : FY08 failure analysis...

    Office of Scientific and Technical Information (OSTI)

    analysis activities. Citation Details In-Document Search Title: The Sandia MEMS Passive Shock Sensor : FY08 failure analysis activities. No abstract prepared. Authors:...

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

    E-Print Network [OSTI]

    Green, M.A.

    2010-01-01

    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

  9. Wind Turbine Gearbox Failure Modes - A Brief (Presentation)

    SciTech Connect (OSTI)

    Sheng, S.; McDade, M.; Errichello, R.

    2011-10-01

    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.

  10. Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...

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

    Capabilities at the High Temperature Materials Laboratory and HTML User Program Success Stories Failure Stress and Apparent Elastic Modulus of Diesel Particulate Filter Ceramics...

  11. Pattern of Failure After Limited Margin Radiotherapy and Temozolomide for Glioblastoma

    SciTech Connect (OSTI)

    McDonald, Mark W.; Shu, Hui-Kuo G.; Curran, Walter J.; Crocker, Ian R.

    2011-01-01

    Purpose: To evaluate the pattern of failure after limited margin radiotherapy for glioblastoma. Methods and Materials: We analyzed 62 consecutive patients with newly diagnosed glioblastoma treated between 2006 and 2008 with standard fractionation to a total dose of 60Gy with concurrent temozolomide (97%) or arsenic trioxide (3%). The initial clinical target volume included postoperative T2 abnormality with a median margin of 0.7cm. The boost clinical target volume included residual T1-enhancing tumor and resection cavity with a median margin of 0.5cm. Planning target volumes added a 0.3- or 0.5-cm margin to clinical target volumes. The total boost planning target volume (PTV{sub boost}) margin was 1cm or less in 92% of patients. The volume of recurrent tumor (new T1 enhancement) was categorized by the percent within the 60-Gy isodose line as central (>95%), infield (81-95%), marginal (20-80%), or distant (<20%). For comparison, an initial planning target volume with a 2-cm margin and PTV{sub boost} with a 2.5-cm margin were created for each patient. Results: With a median follow-up of 12 months, radiographic tumor progression developed in 43 of 62 patients. Imaging was available for analysis in 41: 38 (93%) had central or infield failure, 2 (5%) had marginal failure, and 1 (2%) had distant failure relative to the 60-Gy isodose line. The treated PTV{sub boost} (median, 140cm{sup 3}) was, on average, 70% less than the PTV{sub boost} with a 2.5-cm margin (median, 477cm{sup 3}) (p < 0.001). Conclusions: A PTV{sub boost} margin of 1cm or less did not appear to increase the risk of marginal and/or distant tumor failures compared with other published series. With careful radiation planning and delivery, it appears that treatment margins for glioblastoma can be reduced.

  12. Preventing aneuploidy and the consequences of failure

    E-Print Network [OSTI]

    Prabhu, Vineet R. (Vineet Ranjan)

    2009-01-01

    The maintenance and transmission of genetic material is critical for the survival of cells and organisms. Sexually reproducing diploid organisms undergo meiosis to produce haploid gametes, so that the resulting progeny are ...

  13. Scintillator material

    DOE Patents [OSTI]

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    1994-01-01

    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.

  14. Scintillator material

    DOE Patents [OSTI]

    Anderson, David F. (Batavia, IL); Kross, Brian J. (Aurora, IL)

    1992-01-01

    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.

  15. Scintillator material

    DOE Patents [OSTI]

    Anderson, D.F.; Kross, B.J.

    1994-06-07

    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.

  16. Scintillator material

    DOE Patents [OSTI]

    Anderson, D.F.; Kross, B.J.

    1992-07-28

    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.

  17. A Numeric Predictive Failure Model for Percussive Excavation

    E-Print Network [OSTI]

    Green, Alex Nicholas

    2011-01-01

    Journal of the Soil mechanics and Foundations Division, ASCEConference on Soil Mechanics and Foundation Engineering,Journal of the Soil Mechanics and Foundations Division,

  18. An Integrated Approach to Modeling and Mitigating SOFC Failure

    SciTech Connect (OSTI)

    Jianmin Qu; Andrei Fedorov; Comas Haynes

    2006-05-15

    The specific objectives of this project were: (1) To develop and demonstrate the feasibility of an integrated predictive computer-based tool for fuel cell design and reliability/durability analysis, (2) To generate new scientific and engineering knowledge to better enable SECA Industry Teams to develop reliable, low-cost solid-oxide fuel cell power generation systems, (3) To create technology breakthroughs to address technical risks and barriers that currently limit achievement of the SECA performance and cost goals for solidoxide fuel cell systems, and (4) To transfer new science and technology developed in the project to the SECA Industry Teams. Through this three-year project, the Georgia Tech's team has demonstrated the feasibility of the solution proposed and the merits of the scientific path of inquiry, and has developed the technology to a sufficient level such that it can be utilized by the SECA Industry Teams. This report summarizes the project's results and achievements.

  19. An interaction model for simulation and mitigation of cascading failures |

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TAPropaneandAn Overview ofArgonne National

  20. material recovery

    National Nuclear Security Administration (NNSA)

    dispose of dangerous nuclear and radiological material, and detect and control the proliferation of related WMD technology and expertise.

  1. Materials for solid state lighting

    SciTech Connect (OSTI)

    Johnson, S.G.; Simmons, J.A.

    2002-03-26

    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.

  2. 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))

    1991-08-01

    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.

  3. Cookoff of energetic materials

    SciTech Connect (OSTI)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J.; Schmitt, R.G.

    1998-09-01

    An overview of cookoff modeling at Sandia National Laboratories is presented aimed at assessing the violence of reaction following cookoff of confined energetic materials. During cookoff, the response of energetic materials is known to involve coupled thermal/chemical/mechanical processes which induce thermal damage to the energetic material prior to the onset of ignition. These damaged states enhance shock sensitivity and lead to conditions favoring self-supported accelerated combustion. Thus, the level of violence depends on the competition between pressure buildup and stress release due to the loss of confinement. To model these complex processes, finite element-based analysis capabilities are being developed which can resolve coupled heat transfer with chemistry, quasi-static structural mechanics and dynamic response. Numerical simulations that assess the level of violence demonstrate the importance of determining material damage in pre- and post-ignition cookoff events.

  4. Cermet materials

    DOE Patents [OSTI]

    Kong, Peter C. (Idaho Falls, ID)

    2008-12-23

    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.

  5. 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)

    2012-02-07

    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.

  6. Complex systems analysis of series of blackouts: cascading failure, critical points, and self-organization

    SciTech Connect (OSTI)

    Dobson, Ian [University of Wisconsin, Madison; Carreras, Benjamin A [ORNL; Lynch, Vickie E [ORNL; Newman, David E [University of Alaska

    2007-01-01

    We give an overview of a complex systems approach to large blackouts of electric power transmission systems caused by cascading failure. Instead of looking at the details of particular blackouts, we study the statistics and dynamics of series of blackouts with approximate global models. Blackout data from several countries suggest that the frequency of large blackouts is governed by a power law. The power law makes the risk of large blackouts consequential and is consistent with the power system being a complex system designed and operated near a critical point. Power system overall loading or stress relative to operating limits is a key factor affecting the risk of cascading failure. Power system blackout models and abstract models of cascading failure show critical points with power law behavior as load is increased. To explain why the power system is operated near these critical points and inspired by concepts from self-organized criticality, we suggest that power system operating margins evolve slowly to near a critical point and confirm this idea using a power system model. The slow evolution of the power system is driven by a steady increase in electric loading, economic pressures to maximize the use of the grid, and the engineering responses to blackouts that upgrade the system. Mitigation of blackout risk should account for dynamical effects in complex self-organized critical systems. For example, some methods of suppressing small blackouts could ultimately increase the risk of large blackouts.

  7. Optimal Test Distributions for Software Failure Cost Walter J. Gutjahr

    E-Print Network [OSTI]

    Gutjahr, Walter

    Optimal Test Distributions for Software Failure Cost Estimation Walter J. Gutjahr Department, reliability estimation, risk assessment, software failure costs, software reliability, software testing. I in a software quality assurance process, to be performed after a testing phase oriented on fault detection. Let

  8. Coding Hazardous Tree Failures for a Data Management System

    E-Print Network [OSTI]

    Standiford, Richard B.

    Terms: hazard trees; hazard reduction; recreation areas; urban forestry; safety standards; dataCoding Hazardous Tree Failures for a Data Management System Lee A. Paine PACIFIC SOUTHWEST hazardous tree failures for a data management system. Gen. Tech. Rep. PSW-29, 108 p., illus. Pacific

  9. A UNIFIED FAILURE/DAMAGE APPROACH TO BATTLE DAMAGE REGENERATION

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A UNIFIED FAILURE/DAMAGE APPROACH TO BATTLE DAMAGE REGENERATION : APPLICATION TO GROUND MILITARY-availability. Military weapon systems availability can be affected by system failures or by damage to the system damage into account in their more general dependability studies. This paper takes a look at the issues

  10. FAILURE MODES AND EFFECTS ANALYSIS Dated: May 27, 2010

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    1 NSTX FAILURE MODES AND EFFECTS ANALYSIS (FMEA) Revision 7 Dated: May 27, 2010 Prepared By: Name.07.13 09:11:02 -04'00' #12;NSTX Failure Modes & Effects Analysis / NSTX-FMEA-71-7 / p. 2 of 120 2 Table

  11. Fast Recovery From Link Failures in Ethernet Networks

    E-Print Network [OSTI]

    Ramasubramanian, Srinivasan

    1 Fast Recovery From Link Failures in Ethernet Networks Abishek Gopalan and Srinivasan,srini}@ece.arizona.edu Abstract--Fast-recovery from link failures is a well-studied topic in IP networks. Employing fast, switches employ backward learning to populate the forwarding table entries. Thus, any fast recovery

  12. Common Trends in Software Fault and Failure Data

    E-Print Network [OSTI]

    Goseva-Popstojanova, Katerina

    Common Trends in Software Fault and Failure Data Maggie Hamill, Member, IEEE, and Katerina Goseva with the findings from related studies. The consistency of several main trends across software systems in this paper-Popstojanova, Senior Member, IEEE Abstract--The benefits of the analysis of software faults and failures have been

  13. The role of environmental assumptions in failures of DNA nanosystems

    E-Print Network [OSTI]

    Lutz, Robyn R.

    describe the structure of a failure catalog for DNA nanosystems that we have prototyped for use by molecular programmers. We hypothesize that the failure frame approach and catalog can be broadly useful if and only if the plane is moving on the runway [4]. In fact, when the plane was aquaplaning on a water

  14. Financial Cash Flow Determinants of Company Failure in the Construction

    E-Print Network [OSTI]

    Kamat, Vineet R.

    Financial Cash Flow Determinants of Company Failure in the Construction Industry by Ihab to thank my family. They have always been a source of inspiration, encouragement and love, and I would xi Chapter 1: Introduction 1 1.1 Construction Company Failure Statistics 6 1.2 Overview

  15. Energy Efficiency and Renewables: Market and Behavioral Failures

    ScienceCinema (OSTI)

    James Sweeney

    2010-09-01

    Thursday, January 28, 2010: Policies to promote renewable energy and energy efficiency have been gaining momentum throughout the world, often justified by environmental and energy security concerns. This presentation first talks about energy efficiency options, then delves into the economic motivation for energy efficiency and renewable energy policies by articulating the classes of relevant behavioral failures and market failures. Such behavioral and market failures may vary intertemporally or atemporally; the temporal structure and the extent of the failures are the critical considerations in the development of energy policies. The talk discusses key policy instruments and assess the extent to which they are well-suited to correct for failures with different structures. http://eetd.lbl.gov/dls/lecture-01-28...

  16. Model Based Safety Assessment Dynamic System

    E-Print Network [OSTI]

    Grigoras, .Romulus

    Assessment Techniques ·Failure mode and effect analysis (FMEA) ­ Model: from a local failure to its system chain .... 2 Functional FMEA template FT unannunciated loss of wheel braking #12;Drawbacks of the Classical Safety Assessment Techniques · Fault Tree, FMEA ­ Give failure propagation paths without referring

  17. MULTISCALE PHENOMENA IN MATERIALS

    SciTech Connect (OSTI)

    A. BISHOP

    2000-09-01

    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.

  18. Recovery systems must save state before a failure occurs to enable the system to recover from the failure. However,

    E-Print Network [OSTI]

    Chen, Peter M.

    Abstract Recovery systems must save state before a failure occurs to enable the system to recover from the failure. However, recovery will fail if the recovery system saves any state corrupted by the fault. The frequency and comprehensive- ness of how a recovery system saves state has a major effect

  19. Nuclear fuel elements made from nanophase materials

    DOE Patents [OSTI]

    Heubeck, Norman B. (Schenectady, NY)

    1998-01-01

    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.

  20. Nuclear fuel elements made from nanophase materials

    DOE Patents [OSTI]

    Heubeck, N.B.

    1998-09-08

    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.

  1. Dynamic crack initiation toughness : experiments and peridynamic modeling.

    SciTech Connect (OSTI)

    Foster, John T.

    2009-10-01

    This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model is then validated against one class of problems showing good agreement with experimental results.

  2. Complex Materials

    SciTech Connect (OSTI)

    Cooper, Valentino

    2014-04-17

    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.

  3. Complex Materials

    ScienceCinema (OSTI)

    Cooper, Valentino

    2014-05-23

    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.

  4. material removal

    National Nuclear Security Administration (NNSA)

    %2A en Nuclear Material Removal http:www.nnsa.energy.govaboutusourprogramsdnnm3remove

    Pag...

  5. Propulsion materials

    SciTech Connect (OSTI)

    Wall, Edward J.; Sullivan, Rogelio A.; Gibbs, Jerry L.

    2008-01-01

    The Department of Energy’s (DOE’s) Office of Vehicle Technologies (OVT) is pleased to introduce the FY 2007 Annual Progress Report for the Propulsion Materials Research and Development Program. Together with DOE national laboratories and in partnership with private industry and universities across the United States, the program continues to engage in research and development (R&D) that provides enabling materials technology for fuel-efficient and environmentally friendly commercial and passenger vehicles.

  6. Size-dependent mechanical properties of beta-structures in protein materials

    E-Print Network [OSTI]

    Keten, Sinan

    2010-01-01

    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 ...

  7. Unusual refinery boiler tube failures due to corrosion by sulfuric acid induced by steam leaks

    SciTech Connect (OSTI)

    Lopez-Lopez, D.; Wong-Moreno, A.

    1998-12-31

    Corrosion by sulfuric acid in boilers is a low probability event because gas temperature and metal temperature of boiler tubes are high enough to avoid the condensation of sulfuric acid from flue gases. This degradation mechanism is frequently considered as an important cause of air preheaters materials degradation, where flue gases are cooled by heat transfer to the combustion air. Corrosion is associated to the presence of sulfuric acid, which condensates if metal temperature (or gas temperature) is below of the acid dew point. In economizer tubes, sulfuric acid corrosion is an unlikely event because flue gas and tube temperatures are normally over the acid dewpoint. In this paper, the failure analysis of generator tubes (similar to the economizer of bigger boilers) of two small oil-fired subcritical boilers is reported. It is concluded that sulfuric acid corrosion was the cause of the failure. The sulfuric acid condensation was due to the contact of flue gases containing SO{sub 3} with water-steam spray coming from leaks at the interface of rolled tube to the drum. Considering the information gathered from these two cases studied, an analysis of this failure mechanism is presented including a description of the thermodynamics condition of water leaking from the drum, and an analysis of the factors favoring it.

  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

    2010-11-17

    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. Analytical Study on Adhesively Bonded Joints Using Peeling Test and Symmetric Composite Models Based on Bernoulli-Euler and Timoshenko Beam Theories for Elastic and Viscoelastic Materials 

    E-Print Network [OSTI]

    Su, Ying-Yu

    2012-02-14

    , ??????, ?????. The adherend material is aluminium, and the adhesive is an epoxy. The properties of these two materials are ???????? ???????? ??? ?????? [15]. 24 2.7.1 Loading Mode I In this case, the horizontal forces are not considered, and the solution...

  10. Investigation and modeling of processing-microstructure-property relations in ultra-fine grained hexagonal close packed materials under strain path changes 

    E-Print Network [OSTI]

    Yapici, Guney Guven

    2009-05-15

    Ultra-fine grained (UFG) materials have attracted considerable interest due to the possibility of achieving simultaneous increase in strength and ductility. Effective use of these materials in engineering applications ...

  11. Making, Measuring, and Modeling 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion toMSDS on theMaitrayeeEnergyMaking a

  12. Hardfacing material

    DOE Patents [OSTI]

    Branagan, Daniel J. (Iona, ID)

    2012-01-17

    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.

  13. Congestive heart failure: treat the disease, not the symptom: return to normalcy/Part II--the experimental approach.

    E-Print Network [OSTI]

    Buckberg, Gerald D

    2007-01-01

    Number: Title: Congestive heart failure: treat the diseaseinvited) TITLE: Congestive heart failure: treat the diseasetreatment of congestive heart failure due to post-infarction

  14. INSTITUTE OF PHYSICS PUBLISHING MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING Modelling Simul. Mater. Sci. Eng. 14 (2006) 13631396 doi:10.1088/0965-0393/14/8/006

    E-Print Network [OSTI]

    Ghosh, Somnath

    2006-01-01

    , ductility and fracture toughness requires special attention on the microstructural morphology. Various and alignment or irregularities in phase shapes and sizes. Experimental studies on ductile failure in [1­4] have to particulate cracking and interfacial decohesion, as well as ductile damage growth by matrix rupture due

  15. Gearbox Reliability Collaborative Gearbox 1 Failure Analysis Report: December 2010 - January 2011

    SciTech Connect (OSTI)

    Errichello, R.; Muller, J.

    2012-02-01

    Unintended gearbox failures have a significant impact on the cost of wind farm operations. In 2007, NREL initiated the Gearbox Reliability Collaborative (GRC). The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database in a multi-pronged approach to determine why wind turbine gearboxes do not achieve their expected design life. The collaborative of manufacturers, owners, researchers, and consultants focuses on gearbox testing and modeling and the development of a gearbox failure database. Collaborative members also investigate gearbox condition monitoring techniques. Data gained from the GRC will enable designers, developers, and manufacturers to improve gearbox designs and testing standards and create more robust modeling tools. GRC project essentials include the development of two identical, heavily instrumented representative gearbox designs. Knowledge gained from the field and dynamometer tests conducted on these gearboxes builds an understanding of how the selected loads and events translate into bearing and gear response. This report contains the analysis of the first gearbox design.

  16. Using Genetic Algorithms to Search for Failure Scenarios Kevin Mills, James Filliben and Chris Dabrowski from NIST

    E-Print Network [OSTI]

    Using Genetic Algorithms to Search for Failure Scenarios Kevin Mills, James Filliben and Chris Dabrowski from NIST We are investigating the use of genetic algorithms (GAs) to steer system models degradations. Koala Simulator Distribution of Anti-Fitness Scenarios Discovered by the Genetic Algorithm http

  17. Reliability analysis for wind turbines with incomplete failure data collected from after the date of initial installation

    E-Print Network [OSTI]

    McCalley, James D.

    . Walford outlined the issues relevant to wind turbine reliability for wind turbine power generation generation and wind speed models to analyze power production reliability [3,4]. Others have appliedReliability analysis for wind turbines with incomplete failure data collected from after the date

  18. Platform failures : lessons for strategic management

    E-Print Network [OSTI]

    Vardhan, Harsh, S.M. Massachusetts Institute of Technology

    2015-01-01

    Most internet business models today are positioned as platforms that connect two or more groups of users. From online social networking to electronic retail, we find that multi-sided platforms are penetrating consumers' ...

  19. Terrestrial Photovoltaic Module Accelerated Test-To-Failure Protocol

    SciTech Connect (OSTI)

    Osterwald, C. R.

    2008-03-01

    This technical report documents a test-to-failure protocol that may be used to obtain quantitative information about the reliability of photovoltaic modules using accelerated testing in environmental temperature-humidity chambers.

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

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

    Transport and Failure in Li-ion Batteries Monday, February 13, 2012 - 1:30pm SSRL Conference Room 137-322 Stephen J. Harris, General Motors R&D While battery performance is well...