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Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

A frequency domain finite element model for tidal circulation  

E-Print Network (OSTI)

A highly efficient finite element model has been developed for the numerical prediction of depth average circulation within small scale embayments which are often characterized by irregular boundaries and bottom topography.

Westerink, Joannes J.

1985-01-01T23:59:59.000Z

2

A finite element model for three dimensional hydraulic fracturing  

Science Conference Proceedings (OSTI)

This paper is devoted to the development of a model for the numerical simulation of hydraulic fracturing processes with 3d fracture propagation. It takes into account the effects of fluid flow inside the fracture, fluid leak-off through fracture walls ... Keywords: boundary elements, finite elements, hydraulic fracturing, petroleum recovery

Philippe R. B. Devloo; Paulo Dore Fernandes; Snia M. Gomes; Cedric Marcelo Augusto Ayala Bravo; Renato Gomes Damas

2006-11-01T23:59:59.000Z

3

Efficient Finite Element Modeling of Shallow Geothermal Systems  

Science Conference Proceedings (OSTI)

This paper presents a finite element modeling technique for double U-tube borehole heat exchangers (BHE) and the surrounding soil mass. Focus is placed on presenting numerical analyses describing the capability of a BHE model, previously introduced by ... Keywords: Geothermic, BHE, Heat transfer

Rafid Al-Khoury

2009-12-01T23:59:59.000Z

4

Finite Element Modeling of Pharmaceutical Powder Compaction ...  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): A Comparative ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

5

Finite element modeling of borehole heat exchanger systems  

Science Conference Proceedings (OSTI)

Single borehole heat exchanger (BHE) and arrays of BHE are modeled by using the finite element method. Applying BHE in regional discretizations optimal conditions of mesh spacing around singular BHE nodes are derived. Optimal meshes have shown superior ... Keywords: Borehole heat exchanger, Borehole thermal energy store, FEFLOW, TRNSYS

H. -J. G. Diersch; D. Bauer; W. Heidemann; W. Rhaak; P. Schtzl

2011-08-01T23:59:59.000Z

6

Development of a Two-Dimensional Finite-Element PBL Model and Two Preliminary Model Applications  

Science Conference Proceedings (OSTI)

We have developed a two-dimensional finite-element model for simulating atmospheric flow in the planetary boundary layer (PBL) of the earth. The finite-element method provides a useful alternative to the conventional finite-difference method in ...

L. P. Chang; E. S. Takle; R. L. Sani

1982-12-01T23:59:59.000Z

7

Energy conserving Anisotropic Anhysteretic Magnetic Modelling for Finite Element Analysis  

E-Print Network (OSTI)

To model ferromagnetic material in finite element analysis a correct description of the constitutive relationship (BH-law) must be found from measured data. This article proposes to use the energy density function as a centrepiece. Using this function, which turns out to be a convex function of the flux density, guarantees energy conservative modelling. The magnetic field strength can be seen as a derivative with respect to the flux density. Especially for anisotropic materials (from lamination and/or grain orientation) this method has advantages. Strictly speaking this method is only valid for anhysteretic and thermodynamically stable material.

Jens Krause

2012-12-20T23:59:59.000Z

8

Modelling well leakage in multilayer aquifer systems using the extended finite element method  

Science Conference Proceedings (OSTI)

The extended finite element method (XFEM) is applied to the problem of predicting the steady-state leakage from layered sedimentary aquifer systems perforated by abandoned wells. Multi-aquifer systems are modelled using a quasi-three-dimensional model ... Keywords: Extended finite element method, GFEM, Generalised finite element method, Leakage, Multi-aquifer systems, XFEM

Robert Gracie; James R. Craig

2010-06-01T23:59:59.000Z

9

Surface photovoltage measurements and finite element modeling of SAW devices.  

Science Conference Proceedings (OSTI)

Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.

Donnelly, Christine

2012-03-01T23:59:59.000Z

10

Calculation of gas hydrate dissociation with finite-element model  

SciTech Connect

In situ gas hydrates have been found abundantly in the Arctic regions of the US, Canada, and Russia. Gas recovery from such a hydrate reservoir under permafrost conditions is described in the present paper. The technique is based upon a finite-element transient heat-conduction model that includes the ability to handle phase change. That model is applied to field data available from the North Slope of Alaska for predicting natural-gas production. Parametric studies have also been conducted to explore the effects of hydrate zone thickness, wellbore temperature, wellbore radius, porosity, etc., on the gas production rate. Comparisons of temperature distributions throughout the medium, and the propagation of the moving dissociation front with respect to time predicted by the present scheme and a finite-difference scheme, show good agreement. The data generated in the present study may be useful in deciding on the most optimal technique for gas recovery from hydrates. Additionally, it may provide drilling engineers with valuable information to establish guidelines for safe drilling in the presence of hydrates.

Das, D.K.; Srivastava, V. (Univ. of Alaska, Fairbanks, AK (United States). Mechanical Engineering Dept.)

1993-12-01T23:59:59.000Z

11

Nonlinear geometrically adaptive finite element model of the coilbox  

Science Conference Proceedings (OSTI)

Hot bar heat loss in the transfer table, the rolling stage between rougher stands and finishing stands in a hot mill, is of major concern for reasons for energy consumption, metallurgical uniformity, and rollability. A mathematical model, as well as the corresponding numerical solution, is presented for the evolution of temperature in a coiling and uncoiling bar in hot mills in the form of a parabolic partial differential equation for a shape-changing domain. The space discretization is achieved via a computationally efficient geometrically adaptive finite element scheme that accommodates the change in shape of the domain, using a computationally novel treatment of the resulting thermal contact problem due to coiling. Time is discretized according to a Crank-Nicolson scheme. Finally, some numerical results are presented.

Troyani, N. [Univ. de Oriente, Puerto La Cruz (Venezuela). Dept. de Mecanica

1996-12-01T23:59:59.000Z

12

Modeling of interfaces in two-dimensional problems using solid finite elements with high aspect ratio  

Science Conference Proceedings (OSTI)

The use of standard solid finite elements with a very high aspect ratio is proposed to model the behavior of thin interface regions between distinct components of composite structural members. It is shown that these elements present the same kinematics ... Keywords: Bond-slip, Damage model, Finite elements, Interface model, Reinforced concrete, Strong discontinuity

O. L. Manzoli; A. L. Gamino; E. A. Rodrigues; G. K. S. Claro

2012-03-01T23:59:59.000Z

13

FEWA: a Finite Element model of Water flow through Aquifers  

Science Conference Proceedings (OSTI)

This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables.

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

1983-11-01T23:59:59.000Z

14

Calibration under uncertainty for finite element models of masonry monuments  

SciTech Connect

Historical unreinforced masonry buildings often include features such as load bearing unreinforced masonry vaults and their supporting framework of piers, fill, buttresses, and walls. The masonry vaults of such buildings are among the most vulnerable structural components and certainly among the most challenging to analyze. The versatility of finite element (FE) analyses in incorporating various constitutive laws, as well as practically all geometric configurations, has resulted in the widespread use of the FE method for the analysis of complex unreinforced masonry structures over the last three decades. However, an FE model is only as accurate as its input parameters, and there are two fundamental challenges while defining FE model input parameters: (1) material properties and (2) support conditions. The difficulties in defining these two aspects of the FE model arise from the lack of knowledge in the common engineering understanding of masonry behavior. As a result, engineers are unable to define these FE model input parameters with certainty, and, inevitably, uncertainties are introduced to the FE model.

Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin

2010-02-01T23:59:59.000Z

15

Finite element modeling of transmission line under downburst wind loading  

Science Conference Proceedings (OSTI)

Despite the fact that extensive research has been carried out on transmission lines subjected to normal wind loads, their behaviour under high intensity wind loads (HIW), such as downburst, is poorly defined. This paper describes a detailed numerical ... Keywords: Downbursts, Finite element, Microbursts, Transmission line, Transmission tower, Wind load

A. Y. Shehata; A. A. El Damatty; E. Savory

2005-10-01T23:59:59.000Z

16

Developing a time-domain finite-element method for modeling of electromagnetic cylindrical cloaks  

Science Conference Proceedings (OSTI)

In this paper we propose a time-domain finite element method for modeling of electromagnetic cloaks. The permittivity and permeability of the cloak model are described by the Drude dispersion model. The model to be solved is quite challenging in that ... Keywords: Finite element method, Invisibility cloak, Maxwell's equations

Jichun Li; Yunqing Huang; Wei Yang

2012-04-01T23:59:59.000Z

17

FEMA: a Finite Element Model of Material Transport through Aquifers  

Science Conference Proceedings (OSTI)

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

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

1985-01-01T23:59:59.000Z

18

High dimensional model representation based formulations for fuzzy finite element analysis of structures  

Science Conference Proceedings (OSTI)

This paper presents a practical approach based on high dimensional model representation (HDMR) for analyzing the response of structures with fuzzy parameters. The proposed methodology involves integrated finite element modeling, HDMR based response surface ... Keywords: Explicit formulation, Finite element, Fuzzy analysis, High dimensional model representation, Implicit formulation, Response surface

A. S. Balu; B. N. Rao

2012-03-01T23:59:59.000Z

19

Time domain 3D finite element modelling of train-induced vibration at high speed  

Science Conference Proceedings (OSTI)

The purpose of this paper is to investigate a 3D finite element (FE) coupled train-track model for the numerical modelling of the ground induced vibration due to the passage of a single high speed train locomotive. The track components such as the sleepers, ... Keywords: Finite elements, Ground vibration, High-speed, Mach cone, Railways

A. El Kacimi; P. K. Woodward; O. Laghrouche; G. Medero

2013-03-01T23:59:59.000Z

20

Finite element implementation of nearly-incompressible rheological models based on multiplicative decompositions  

Science Conference Proceedings (OSTI)

The present work is concerned with the numerical integration of finite viscoelastic or viscoplastic models. A numerical integration scheme based on the definition of a flow direction and a flow amplitude as in elastoplasticity is proposed. The most original ... Keywords: Finite elements, Finite strain, Integration scheme, Viscoelasticity, Viscoplasticity

S. Lejeunes; A. Boukamel; S. Mo

2011-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Finite element modelling of the neck-stem interface of a modular hip implant for micro-motion study  

Science Conference Proceedings (OSTI)

A three dimensional, non-linear finite element modelling was used to analyse component stresses and relative micromotion at the modular junction interface of a Ti-alloy modular hip implant, using ANSYS finite element software. The model was developed ... Keywords: biomechanical modelling, finite element modelling, fretting, micromotion, modular hip stem

Kassim A. Abdullah

2008-08-01T23:59:59.000Z

22

Quadratic Galerkin Finite Element Schemes for the Vertical Discretization of Numerical Forecast Models  

Science Conference Proceedings (OSTI)

A finite element scheme with second-order basis functions is introduced for vertical discretization using a spectral model for horizontal discretization. The basis functions are required to be continuous, and no assumption is made concerning the ...

J. Steppeler

1987-08-01T23:59:59.000Z

23

TEA - a linear frequency domain finite element model for tidal embayment analysis  

E-Print Network (OSTI)

A frequency domain (harmonic) finite element model is developed for the numerical prediction of depth average circulation within small embayments. Such embayments are often characterized by irregular boundaries and bottom ...

Westerink, Joannes J.

1984-01-01T23:59:59.000Z

24

Constitutive model effects on finite element modeling of elastomer behavior in radial interference seal configurations  

E-Print Network (OSTI)

Elastomers are becoming more prevalent in everyday products, and it is very important to be able to describe their behavior. Particularly, with advancements in computer hardware and software, the use of finite element analysis in design and analysis is becoming more prevalent. However, there is no accepted and agreed upon method to generally describe elastomer behavior in the finite element codes. Evaluation of two existing material models found in most FEA packages was conducted using experimental data gathered and fit to each model's strain energy function. The effects of using various combinations of material model and experimental data have been studied. The modeling started with simple stress states and progressed to some more general in nature. The two strain energy fimctions used were the Mooney-Rivlin and a 5 term expansion of the Rivlin series called the Polynomial (N=2) function.

Jackson, Jason R.

1996-01-01T23:59:59.000Z

25

Partial delamination modeling in composite beams using a finite element method  

Science Conference Proceedings (OSTI)

A new method of modeling partial delamination in composite beams is proposed and implemented using the finite element method. Homogenized cross-sectional stiffness of the delaminated beam is obtained by the proposed analytical technique, including extension-bending, ... Keywords: Beam element, Composites, Delamination, Timoshenko beam, Vibration

S. Keshava Kumar, Ranjan Ganguli, Dineshkumar Harursampath

2013-11-01T23:59:59.000Z

26

Variational Data Assimilation with a Variable Resolution Finite-Element shallow-water Equations Model  

Science Conference Proceedings (OSTI)

The adjoint model of a finite-element shallow-water equations model was obtained with a view to calculate the gradient of a cost functional in the framework of using this model to carry out variational data assimilation (VDA) experiments using ...

Keyun Zhu; I. Michael Navon; Xiaolei Zou

1994-05-01T23:59:59.000Z

27

Effects of Stochastic Ice Strength Perturbation on Arctic Finite Element Sea Ice Modeling  

Science Conference Proceedings (OSTI)

The ice strength parameter P* is a key parameter in dynamic/thermodynamic sea ice models that cannot be measured directly. Stochastically perturbing P* in the Finite Element Sea IceOcean Model (FESOM) of the Alfred Wegener Institute aims at ...

Stephan Juricke; Peter Lemke; Ralph Timmermann; Thomas Rackow

2013-06-01T23:59:59.000Z

28

Three dimensional modeling and finite element simulation of a generic end mill  

Science Conference Proceedings (OSTI)

The geometry of cutting flutes and the surfaces of end mills is one of the crucial parameters affecting the quality of the machining in the case of end milling. These are usually represented by two-dimensional models. This paper describes in detail the ... Keywords: End mill, Finite element analysis, Mapping, Surface modeling, Surface patches

Puneet Tandon; Md. Rajik Khan

2009-02-01T23:59:59.000Z

29

Patient-Specific Finite Element Models of Proximal Femur Stiffness ...  

Science Conference Proceedings (OSTI)

Models were validated experimentally by fracturing human cadaveric femurs in a testing machine, using specially designed fixtures, load cells, and high speed...

30

Flexible finite-element modeling of global geomagnetic depth sounding  

E-Print Network (OSTI)

Modeling in 2D and 3D for Geomagnetic Depth Sounding (31, 16610. Banks, R. , 1969: Geomagnetic variations and the1997: Introduction to geomagnetic fields. Cambridge Univ Pr.

Ribaudo, Joseph Thomas

2011-01-01T23:59:59.000Z

31

Heat Transport in Groundwater Systems--Finite Element Model  

E-Print Network (OSTI)

Solar energy is a promising alternate energy source for space heating. A method of economic long term solar energy storage is needed. Researchers have proposed storing solar energy by injecting hot water heated using solar collectors into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives of this study were to construct a laboratory model to simulate hot water injection into a confined aquifer, to use data from the model to verify analytical solutions modeling this process, and to evaluate the effects of physical properties and design parameters on thermal recovery efficiency. Initial studies of hot water injection into underground reservoirs were done by the petroleum industry while studying secondary and tertiary oil recovery methods. These studies involved small laboratory models. Advances in computer technology made it possible to model these systems numerically. Many assumptions must be made to predict temperature distributions and thermal efficiencies using analytical models which are not required in numerical solutions. To simulate hot water injection into a confined aquifer, a laboratory model (a 1.8288 m deep, 0.2 radian sector tank, that was 7.01 m in the radial direction) was constructed. There were 39 temperature and 15 fluid pressure measuring locations through the model. Water was supplied to the model at a constant temperature and flow rate. The flow layer was composed of a fine grained Texblast blasting sand. Four runs were made. During the initial run, no heat transfer took place and the hydraulic conductivity was measured. Three runs were made where the heat transfer was monitored. Water level data from the heat transfer runs showed that as the temperature of the aquifer increased, the hydraulic conductivity increased. Temperature data indicated that the three radii closest to the well bore reached thermal equilibrium. The equilibrium temperature decreased as radius increased. From Run 1 to Run 2, the equilibrium temperature increased at each radius because a larger flow rate was used. A vertical thermal gradient existed in the flow layer with the less dense warm water floating out over the cooler more dense water initially in the model. During the pumping cycle, the temperatures gradually decreased. The temperature of the water as it was pumped out of the model was measured and the energy recovered was computed using the initial temperature as a reference. Various other temperatures were used as a base reference to calculate recovery efficiency. There were heat losses out the sides of the model. The assumption of angular symmetry made in all analytical solutions was therefore not met. For this reason, the analytical solutions showed adequate, but not great, agreement with the experimental temperature distributions. Using the analytical solutions, the effects of changing system design parameters were evaluated. Increasing thermal conductivity in the flow layer caused the temperature distribution to spread out but had no effect on thermal efficiency. Increasing the thermal conductivity in the confining layers caused the temperature profile to not move as far from the well, and decreased thermal efficiency. Injection rates are only indirectly related to thermal efficiency. The physical parameter having the greatest effect on thermal efficiency was the flow layer thickness. As thickness increased, thermal efficiency increased.

Grubaugh, E. K.; Reddell, D. L.

1980-08-01T23:59:59.000Z

32

Fidelity of a Finite Element Model for Longitudinal Wave Propagation in Thick Cylindrical Wave Guides  

Science Conference Proceedings (OSTI)

The ability to model wave propagation in circular cylindrical bars of finite length numerically or analytically has many applications. In this thesis the capability of an explicit finite element method to model longitudinal waves in cylindrical rods with circular cross-sections is explored. Dispersion curves for the first four modes are compared to the analytical solution to determine the accuracy of various element sizes and time steps. Values for the time step and element size are determined that retain accuracy while minimizing computational time. The modeling parameters are validated by calculating a signal propagated with a broadband input force. Limitations on the applicability are considered along with modeling parameters that should be applicable to more general geometries.

Puckett, A.D.

2000-09-01T23:59:59.000Z

33

Finite element modeling of a vibrating touch screen actuated by piezo patches for haptic feedback  

Science Conference Proceedings (OSTI)

The aim of our work is to design a touch screen for displaying vibrotactile haptic feedback to the user via piezo patches attached to its surface. One of the challenges in the design is the selection of appropriate boundary conditions and the piezo configurations ... Keywords: finite element modeling, piezo patch actuators, touch screen, vibrotactile haptic feedback

Buket Baylan; Ugur Aridogan; Cagatay Basdogan

2012-06-01T23:59:59.000Z

34

Performance of a parallel algebraic multilevel preconditioner for stabilized finite element semiconductor device modeling  

Science Conference Proceedings (OSTI)

In this study results are presented for the large-scale parallel performance of an algebraic multilevel preconditioner for solution of the drift-diffusion model for semiconductor devices. The preconditioner is the key numerical procedure determining ... Keywords: Drift-diffusion, Finite element, Graph partitioning, Multigrid, Multilevel preconditioners, Newton-Krylov, Nonsmoothed aggregation, Schwarz domain decomposition, Semiconductor devices

Paul T. Lin; John N. Shadid; Marzio Sala; Raymond S. Tuminaro; Gary L. Hennigan; Robert J. Hoekstra

2009-09-01T23:59:59.000Z

35

Modeling and computation of two phase geometric biomembranes using surface finite elements  

Science Conference Proceedings (OSTI)

Biomembranes consisting of multiple lipids may involve phase separation phenomena leading to coexisting domains of different lipid compositions. The modeling of such biomembranes involves an elastic or bending energy together with a line energy associated ... Keywords: Lipid bilayer, Multi-component membrane, Numerical simulation, Phase field method, Relaxation dynamics, Surface finite element method

Charles M. Elliott; Bjrn Stinner

2010-09-01T23:59:59.000Z

36

Numerical prediction of aerodynamic characteristics of prismatic cylinder by finite element method with Spalart-Allmaras turbulence model  

Science Conference Proceedings (OSTI)

Aerodynamic characteristic of prismatic cylinders is numerically investigated by using finite element method with Spalart-Allmaras turbulence model. The developed model is verified against the available experimental and numerical results for turbulent ... Keywords: Aerodynamic characteristic, Afterbody shape, Finite element method, Prismatic cylinder, Turbulent flow, Unsteady S-A model

Yan Bao; Dai Zhou; Cheng Huang; Qier Wu; Xiang-qiao Chen

2011-02-01T23:59:59.000Z

37

Implementation of two geologic constitutive models in the HONDO finite-element code  

DOE Green Energy (OSTI)

Two constitutive models for use with geologic materials have been incorporated into the HONDO finite-element program. Both models have the same behavior in tension, using a stress criterion to form cracks normal to the maximum principal stress. In compression, the two models give upper and lower bound solutions to the unconfined postfailure strength. The first model uses a Coulomb criterion to form explicit shear cracks, while the second model uses an elastic-plastic formulation developed by Krieg. Two sample applications, an indentor test and fracture of a borehole, are presented.

Swenson, D.V.

1983-05-01T23:59:59.000Z

38

Introduction to Finite Element Modeling Engineering analysis of mechanical systems have been addressed by deriving differential  

E-Print Network (OSTI)

such as equilibrium, conservation of energy, conservation of mass, the laws of thermodynamics, Maxwell's equations the fundamental ideas of the FEM · Know the behavior and usage of each type of elements covered in this course of the FEM (don't misuse the FEM - a numerical tool) Finite Element Analysis A typical finite element

Lin, Liwei

39

Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites  

E-Print Network (OSTI)

Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading have been analyzed. Elastic moduli and thermal coefficient of expansion are calculated and their variation with diameter and length is investigated. In particular, the nanotubes are modeled using 3D elastic beam finite elements with six degrees of freedom at each node. The difficulty in modeling multi walled nanotubes is the van der Waal's forces between adjacent layers which are geometrically non linear in nature. These forces are modeled using truss elements. The nanotube-polymer interface in a nano-composite is modeled on a similar basis. While performing the molecular dynamic simulations, the geometric optimization is performed initially to obtain the minimized configuration and then the desired temperature is attained by rescaling the velocities of carbon atoms in the nanotube. Results show that the Young's modulus increases with tube diameter in molecular mechanics whereas decreases in molecular dynamics since the inter-atomic potential due to chemical reactions between the atoms is taken into consideration in molecular dynamics unlike in molecular mechanics.

Gaddamanugu, Dhatri

2009-05-01T23:59:59.000Z

40

Modeling of wire-on-tube heat exchangers using finite element method  

Science Conference Proceedings (OSTI)

Wire-on-tube heat exchangers are analysed under normal operating conditions (free convection) using finite element method. Galerkin's weighted residual method is used to minimise the errors. The effects of ambient temperatures and mass flow rates of ... Keywords: finite element method, free convection, phase change, wire on-tube heat exchangers

G. A. Quadir; G. M. Krishnan; K. N. Seetharamu

2002-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Three-dimensional finite element modeling of a magnet array spinning above a conductor  

DOE Green Energy (OSTI)

Drag forces due to eddy currents induced by the relative motion of a conductor and a magnetic field occur in many practical devices: motors, brakes, magnetic bearings, and magnetically levitated vehicles. Recently, finite element codes have included solvers for 3-D eddy current geometries and have the potential to be very useful in the design and analysis of these devices. In this paper, numerical results from three-dimensional modeling of a magnet array spinning above a conductor are compared to experimental results in order to assess the capabilities of these codes.

Lorimer, W.L.; Lieu, D.K. [Univ. of California, Berkeley, CA (United States). Dept. of Mechanical Engineering; Hull, J.R.; Mulcahy, T.M.; Rossing, T.D. [Argonne National Lab., IL (United States)

1993-12-31T23:59:59.000Z

42

An extended finite element method for hydraulic fracture propagation in deformable porous media with the cohesive crack model  

Science Conference Proceedings (OSTI)

In this paper, a fully coupled numerical model is developed for the modeling of the hydraulic fracture propagation in porous media using the extended finite element method in conjunction with the cohesive crack model. The governing equations, which account ... Keywords: Cohesive crack propagation, Fluid flow, Fracturing porous media, Fully coupled model, Hydraulic fracturing, XFEM

T. Mohammadnejad, A. R. Khoei

2013-10-01T23:59:59.000Z

43

Adapting a Beam-Based Rotordynamics Model to Accept a General Three-Dimensional Finite-Element Casing Model  

E-Print Network (OSTI)

The subject of this thesis is an extension of a two-dimensional, axisymmetric, Timoshenko-beam finite-element rotordynamic code to include a three-dimensional non-axisymmetric solid-element casing model. Axisymmetric beams are sufficient to model rotors. Spring and damper forces provide the interface between the rotor and its casing and capture the dynamics of the full model. However, axisymmetric beams limit the modeling of real-case machine structures, where the casing is not axisymmetric. Axisymmetric and non-axisymmetric 3D finite element casing structures are modeled. These structures are then reduced using a technique called substructuring. Modal equations are developed for axisymmetric and non-axisymmetric casing models. In a 3D non-axisymmetric model, structural dynamics modes can be modeled by lateral modes in two orthogonal planes. Modal information of the complex 3D casing structures are generated, and then incorporated into the 2D code after a series of pre-processing steps. A reduction method called Component Mode Synthesis (CMS) is used to reduce the large dimensionality involved in calculation of rotordynamic coefficients. The results from the casing structures are merged with the rotor model to create a combined rotor-casing model. The analysis of the combined structure shows that there is a difference in the natural frequencies and unbalance response between the model that uses symmetrical casing and the one that uses non-axisymmetric casing. XLTRC2 is used as an example of a two-dimensional axisymmetric beam-element code. ANSYS is used as a code to build three-dimensional non-axisymmetric solid-element casing models. The work done in this thesis opens the scope to incorporate complex non-axisymmetric casing models with XLTRC2.

James, Stephen M.

2010-05-01T23:59:59.000Z

44

Least-squares variational principles and the finite element method: theory, formulations, and models for solid and fluid mechanics  

E-Print Network (OSTI)

We consider the application of least-squares variational principles and the finite element method to the numerical solution of boundary value problems arising in the fields of solidand fluidmechanics.For manyof these problems least-squares principles offer many theoretical and computational advantages in the implementation of the corresponding finite element model that are not present in the traditional weak form Galerkin finite element model.Most notably, the use of least-squares principles leads to a variational unconstrained minimization problem where stability conditions such as inf-sup conditions (typically arising in mixed methods using weak form Galerkin finite element formulations) never arise. In addition, the least-squares based finite elementmodelalways yields a discrete system ofequations witha symmetric positive definite coeffcientmatrix.These attributes, amongst manyothers highlightedand detailed in this work, allow the developmentofrobust andeffcient finite elementmodels for problems of practical importance. The research documented herein encompasses least-squares based formulations for incompressible and compressible viscous fluid flow, the bending of thin and thick plates, and for the analysis of shear-deformable shell structures.

Pontaza, Juan Pablo

2003-12-01T23:59:59.000Z

45

Thermo-Poroelastic Modeling of Reservoir Stimulation and Microseismicity Using Finite Element Method with Damage Mechanics  

E-Print Network (OSTI)

Stress and permeability variations around a wellbore and in the reservoir are of much interest in petroleum and geothermal reservoir development. Water injection causes significant changes in pore pressure, temperature, and stress in hot reservoirs, changing rock permeability. In this work, two- and three-dimensional finite element methods were developed to simulate coupled reservoirs with damage mechanics and stress-dependent permeability. The model considers the influence of fluid flow, temperature, and solute transport in rock deformation and models nonlinear behavior with continuum damage mechanics and stress-dependent permeability. Numerical modeling was applied to analyze wellbore stability in swelling shale with two- and three-dimensional damage/fracture propagation around a wellbore and injection-induced microseismic events. The finite element method (FEM) was used to solve the displacement, pore pressure, temperature, and solute concentration problems. Solute mass transport between drilling fluid and shale formation was considered to study salinity effects. Results show that shear and tensile failure can occur around a wellbore in certain drilling conditions where the mud pressure lies between the reservoir pore pressure and fracture gradient. The fully coupled thermo-poro-mechanical FEM simulation was used to model damage/fracture propagation and microseismic events caused by fluid injection. These studies considered wellbore geometry in small-scale modeling and point-source injection, assuming singularity fluid flux for large-scale simulation. Damage mechanics was applied to capture the effects of crack initiation, microvoid growth, and fracture propagation. The induced microseismic events were modeled in heterogeneous geological media, assuming the Weibull distribution functions for modulus and permeability. The results of this study indicate that fluid injection causes the effective stress to relax in the damage phase and to concentrate at the interface between the damage phase and the intact rock. Furthermore, induced-stress and far-field stress influence damage propagation. Cold water injection causes the tensile stress and affects the initial fracture and fracture propagation, but fracture initiation pressure and far-field stress are critical to create a damage/fracture plane, which is normal to the minimum far-field stress direction following well stimulation. Microseismic events propagate at both well scale and reservoir-scale simulation; the cloud shape of a microseismic event is affected by permeability anisotropy and far-field stress, and deviatoric horizontal far-field stress especially contributes to the localization of the microseismic cloud.

Lee, Sang Hoon

2011-12-01T23:59:59.000Z

46

Modeling with finite element the convective heat transfer in civil building EPS insulated walls  

Science Conference Proceedings (OSTI)

In this paper we present the analysis of convective heat transfer in the walls of a house insulated with polystyrene. In the first part we make an evaluation of the insulation that is currently used in the houses. We start the simulation using a real ... Keywords: convective heat transfer, dew-point, finite element, polystyrene insulation

Madalina Xenia Calbureanu; Mihai Lungu; Dragos Tutunea; Raluca Malciu; Alexandru Dima

2010-10-01T23:59:59.000Z

47

A finite-element approximation of a quasi-magnetostatic 3D eddy current model by fractional-step A-? scheme  

Science Conference Proceedings (OSTI)

We propose in this paper a fractional-step A-@j scheme for a quasi-magnetostatic 3D eddy current model by means of finite-element approximations. Bounds for continuous and discrete error in finite time are given, and it is verified that provided the ... Keywords: Eddy current problem, Error estimates, Finite-element approximation, Fractional-step A-? scheme

Changfeng Ma

2004-02-01T23:59:59.000Z

48

Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.  

DOE Green Energy (OSTI)

Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

2012-01-01T23:59:59.000Z

49

Finite element modeling of concentrating solar collectors for evauation of gravity loads, bending, and optical characterization.  

DOE Green Energy (OSTI)

Understanding the effects of gravity and wind loads on concentrating solar power (CSP) collectors is critical for performance calculations and developing more accurate alignment procedures and techniques. This paper presents a rigorous finite-element model of a parabolic trough collector that is used to determine the impact of gravity loads on bending and displacements of the mirror facets and support structure. The geometry of the LUZ LS-2 parabolic trough collector was modeled using SolidWorks, and gravity-induced loading and displacements were simulated in SolidWorks Simulation. The model of the trough collector was evaluated in two positions: the 90{sup o} position (mirrors facing upward) and the 0{sup o} position (mirrors facing horizontally). The slope errors of the mirror facet reflective surfaces were found by evaluating simulated angular displacements of node-connected segments along the mirror surface. The ideal (undeformed) shape of the mirror was compared to the shape of the deformed mirror after gravity loading. Also, slope errors were obtained by comparing the deformed shapes between the 90{sup o} and 0{sup o} positions. The slope errors resulting from comparison between the deformed vs. undeformed shape were as high as {approx}2 mrad, depending on the location of the mirror facet on the collector. The slope errors resulting from a change in orientation of the trough from the 90{sup o} position to the 0{sup o} position with gravity loading were as high as {approx}3 mrad, depending on the location of the facet.

Christian, Joshua M.; Ho, Clifford Kuofei

2010-04-01T23:59:59.000Z

50

Finite element analysis of grain-matrix micro-cracking in shale within the context of a multiscale modeling  

E-Print Network (OSTI)

, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneouslyFinite element analysis of grain-matrix micro-cracking in shale within the context of a multiscale-cracking in shale at grain-matrix inter- faces, assuming constituents are composed of quart silt grains

Regueiro, Richard A.

51

Numerical Prediction of the 1011 June 1985 Squall Line with the Canadian Regional Finite-Element Model  

Science Conference Proceedings (OSTI)

In an effort to improve operational forecasts of mesoscale convective systems (MCSs), a mesoscale version of the operational Canadian Regional Finite-Element (RFE) Model with a grid size of 25 km is used to predict an intense MCS that occurred ...

Stphane Blair; Da-Lin Zhang; Jocelyn Mailhot

1994-06-01T23:59:59.000Z

52

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

by offshore hydrologic instrumentation monitoring in thewith continuous GPS instrumentation and seismic networks [Using Newly Developed Instrumentation and Finite Element

LaBonte, Alison L

2007-01-01T23:59:59.000Z

53

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

by offshore hydrologic instrumentation monitoring in thewith continuous GPS instrumentation and seismic networks [Using Newly Developed Instrumentation and Finite Element

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

54

Utilization of a finite element model to verify spent nuclear fuel storage rack welds  

Science Conference Proceedings (OSTI)

Elastic and plastic finite element analyses were performed for the inner tie block assembly of a 25 port fuel rack designed for installation at the Idaho National Engineering and Environmental Laboratory (INEEL) Idaho Chemical Processing Plant (ICPP). The model was specifically developed to verify the adequacy of certain welds joining components of the fuel storage rack assembly. The work scope for this task was limited to an investigation of the stress levels in the inner tie welds when the rack was subjected to seismic loads. Structural acceptance criteria used for the elastic calculations performed were as defined by the rack`s designer. Structural acceptance criteria used for the plastic calculations performed as part of this effort were as defined in Subsection NF and Appendix F of Section III of the ASME Boiler and Pressure Vessel Code. The results confirm that the welds joining the inner tie block to the surrounding rack structure meet the acceptance criteria. The analysis results verified that the inner tie block welds should be capable of transferring the expected seismic load without structural failure.

Nitzel, M.E.

1998-07-01T23:59:59.000Z

55

Development of Modeling and Simulation for Magnetic Particle Inspection Using Finite Elements  

SciTech Connect

Magnetic particle inspection (MPI) is a widely used nondestructive inspection method for aerospace applications essentially limited to experiment-based approaches. The analysis of MPI characteristics that affect sensitivity and reliability contributes not only reductions in inspection design cost and time but also improvement of analysis of experimental data. Magnetic particles are easily attracted toward a high magnetic field gradient. Selection of a magnetic field source, which produces a magnetic field gradient large enough to detect a defect in a test sample or component, is an important factor in magnetic particle inspection. In this work a finite element method (FEM) has been employed for numerical calculation of the MPI simulation technique. The FEM method is known to be suitable for complicated geometries such as defects in samples. This thesis describes the research that is aimed at providing a quantitative scientific basis for magnetic particle inspection. A new FEM solver for MPI simulation has been developed in this research for not only nonlinear reversible permeability materials but also irreversible hysteresis materials that are described by the Jiles-Atherton model. The material is assumed to have isotropic ferromagnetic properties in this research (i.e., the magnetic properties of the material are identical in all directions in a single crystal). In the research, with a direct current field mode, an MPI situation has been simulated to measure the estimated volume of magnetic particles around defect sites before and after removing any external current fields. Currently, this new MPI simulation package is limited to solving problems with the single current source from either a solenoid or an axial directional current rod.

Jun-Youl Lee

2003-05-31T23:59:59.000Z

56

A study of detonation timing and fragmentation using 3-D finite element techniques and a damage constitutive model  

SciTech Connect

The transient dynamics finite element computer program, PRONTO-3D, has been used in conjunction with a damage constitutive model to study the influence of detonation timing on rock fragmentation during blasting. The primary motivation of this study is to investigate the effectiveness of precise detonators in improving fragmentation. PRONTO-3D simulations show that a delay time of 0.0 sec between adjacent blastholes results in significantly more fragmentation than a 0.5 ms delay.

Preece, D.S.; Thorne, B.J.

1996-03-01T23:59:59.000Z

57

Unified framework for finite element assembly  

Science Conference Proceedings (OSTI)

At the heart of any finite element simulation is the assembly of matrices and vectors from discrete variational forms. We propose a general interface between problem-specific and general-purpose components of finite element programs. This interface ...

M. S. Alnaes; A. Logg; K-A. Mardal; O. Skavhaug; H. P. Langtangen

2009-11-01T23:59:59.000Z

58

Finite-Element Project ABAQUS Tutorial  

E-Print Network (OSTI)

#12;1 Introduction ABAQUS is a finite-element analysis software. Abaqus/CAE provides a pre- processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.6 Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.7 Mesh and postprocessing environment for the analysis of models. It is used in a wide range of industries like automotive

Berlin,Technische Universität

59

Modeling brittle fracture, slip weakening, and variable friction in geomaterials with an embedded strong discontinuity finite element.  

DOE Green Energy (OSTI)

Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report focuses on the development of a constitutive model appropriate to localizing geomaterials, and the embedding of this model into the enhanced finite element framework. This modeling covers two distinct phases. The first, usually brief, phase is the weakening response as the material transitions from intact continuum to a body with a cohesionless fractured surface. Once the cohesion has been eliminated, the response along the surface is completely frictional. We have focused on a rate- and state-dependent frictional model that captures stable and unstable slip along the surface. This model is embedded numerically into the element using a generalized trapezoidal formulation. While the focus is on the constitutive model of interest, the framework is also developed for a general surface response. This report summarizes the major research and development accomplishments for the LDRD project titled 'Cohesive Zone Modeling of Failure in Geomaterials: Formulation and Implementation of a Strong Discontinuity Model Incorporating the Effect of Slip Speed on Frictional Resistance'. This project supported a strategic partnership between Sandia National Laboratories and Stanford University by providing funding for the lead author, Craig Foster, during his doctoral research.

Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA); Foster, C. D. (Stanford University, Stanford, CA)

2006-10-01T23:59:59.000Z

60

Ellipsis 3D: A particle-in-cell finite-element hybrid code for modelling mantle convection and lithospheric deformation  

Science Conference Proceedings (OSTI)

We have extended the two-dimensional geodynamics finite-element code ''Ellipsis'' to three-dimensions. Ellipsis uses a hybrid particle in a cell scheme, which combines a fixed mesh of computational points and a dense arrangement of mobile material points. ... Keywords: Finite-element, Lithosphere, Mantle convection, Mixed scheme, Particle-in-cell

Craig O'Neill; Louis Moresi; Dietmar Mller; Rich Albert; Frdric Dufour

2006-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Finite element modelling and analysis of bolted joints of three dimensional tubular structures  

Science Conference Proceedings (OSTI)

A Hungarian "Steel Cooling Tower Consortium" aimed to develop a new type steel cooling tower, in the framework of a governmental R&D project. Members of the structure are prefabricated tubular elements characterized by high radius-to-thickness ratio. ... Keywords: bolted endplate connection, gusset plate, model development, non-linear FEM, steel cooling tower, thin-walled section, tubular structure, virtual experiment

L. G. Vigh; L. Dunai

2002-09-01T23:59:59.000Z

62

A Study of Frontogenesis Using Finite-Element and Finite-Difference Methods  

Science Conference Proceedings (OSTI)

The accuracy of finite-element and finite-difference methods used to simulate frontogenesis in a six-layer three-dimensional model employing isentropic coordinates is compared. The problem solved is that of an initial height-independent ...

A. K. Macpherson; M. H. Aksel; P. D. Hilton

1980-08-01T23:59:59.000Z

63

The Accuracy of a Finite-Element Vertical Discretization Scheme for Primitive Equation Models: Comparison with a Finite-Difference Scheme  

Science Conference Proceedings (OSTI)

The accuracy of a slightly modified version of the finite-element vertical discretization scheme first described in Staniforth and Daley is studied with respect to a set of Rossby and gravity analytical normal modes obtained as solutions of a ...

Michel Bland; Jean Ct; Andrew Staniforth

1983-12-01T23:59:59.000Z

64

Finite element-based probabilistic analysis tool for orthopaedic applications  

Science Conference Proceedings (OSTI)

Orthopaedic implants, as well as other physical systems, contain inherent variability in geometry, material properties, component alignment, and loading conditions. While complex, deterministic finite element (FE) models do not account for the potential ... Keywords: Finite element modeling, Orthopaedic implants, Probabilistic modeling, Reliability, Sensitivity, Variability

Sarah K. Easley; Saikat Pal; Paul R. Tomaszewski; Anthony J. Petrella; Paul J. Rullkoetter; Peter J. Laz

2007-01-01T23:59:59.000Z

65

Numerical study on transient heat transfer under soil with plastic mulch in agriculture applications using a nonlinear finite element model  

E-Print Network (OSTI)

In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.

De Castro, Carlos Armando

2011-01-01T23:59:59.000Z

66

Explicit finite element analysis of lightly reinforced masonry shear walls  

Science Conference Proceedings (OSTI)

Explicit finite element analysis (FEA) of masonry shear walls containing reinforcement at spacing between 800mm and 2000mm, referred to as wide spaced reinforced masonry (WSRM), are modelled using macroscopic material characteristics for the unreinforced ... Keywords: Characteristic length, Ductility, Explicit finite element method, Failure mode, Masonry shear walls: Reinforced masonry, Quasi-static modelling

M. Dhanasekar; W. Haider

2008-01-01T23:59:59.000Z

67

Solid modeling techniques to build 3D finite element models of volcanic systems: An example from the Rabaul Caldera system, Papua New Guinea  

Science Conference Proceedings (OSTI)

Simulating the deformation of active volcanoes is challenging due to inherent mechanical complexities associated with heterogeneous distributions of rheologic properties and irregular geometries associated with the topography and bathymetry. From geologic ... Keywords: 3D geometry, Deformation, Finite Elements Models, Rabaul Caldera

Erika Ronchin, Timothy Masterlark, Joan Mart Molist, Steve Saunders, Wei Tao

2013-03-01T23:59:59.000Z

68

Finite element simulation of microphotonic lasing system  

SciTech Connect

We present a method for performing time domain simulations of a microphotonic system containing a four level gain medium based on the finite element method. This method includes an approximation that involves expanding the pump and probe electromagnetic fields around their respective carrier frequencies, providing a dramatic speedup of the time evolution. Finally, we present a two dimensional example of this model, simulating a cylindrical spaser array consisting of a four level gain medium inside of a metal shell.

Fietz, Chris; Soukoulis, Costas M.

2012-05-04T23:59:59.000Z

69

A Spectral General Circulation Model Using a Piecewise-Constant Finite-Element Representation on a Hybrid Vertical Coordinate System  

Science Conference Proceedings (OSTI)

A numerical scheme for the vertical discretization of primitive equations in a generalized pressure-type coordinate is developed through application of the Galerkin formalism with piecewise-constant finite elements: this methodology affords an ...

Ren Laprise; Claude Girard

1990-01-01T23:59:59.000Z

70

A Full-wave Model for Wave Propagation and Dissipation in the Inner Magnetosphere Using the Finite Element Method  

Science Conference Proceedings (OSTI)

A wide variety of plasma waves play an important role in the energization and loss of particles in the inner magnetosphere. Our ability to understand and model wave-particle interactions in this region requires improved knowledge of the spatial distribution and properties of these waves as well as improved understanding of how the waves depend on changes in solar wind forcing and/or geomagnetic activity. To this end, we have developed a two-dimensional, finite element code that solves the full wave equations in global magnetospheric geometry. The code describes three-dimensional wave structure including mode conversion when ULF, EMIC, and whistler waves are launched in a two-dimensional axisymmetric background plasma with general magnetic field topology. We illustrate the capabilities of the code by examining the role of plasmaspheric plumes on magnetosonic wave propagation; mode conversion at the ion-ion and Alfven resonances resulting from external, solar wind compressions; and wave structure and mode conversion of electromagnetic ion cyclotron waves launched in the equatorial magnetosphere, which propagate along the magnetic field lines toward the ionosphere. We also discuss advantages of the finite element method for resolving resonant structures, and how the model may be adapted to include nonlocal kinetic effects.

Ernest Valeo, Jay R. Johnson, Eun-Hwa and Cynthia Phillips

2012-03-13T23:59:59.000Z

71

Antenna Optimization By Using Finite Element Programs  

Science Conference Proceedings (OSTI)

Ion Cyclotron Frequency Heating and Current Drive play an important role in fusion experiments. The recent availability of powerful commercial finite element programs for PCs

F. Braun; ICRF Group

2005-01-01T23:59:59.000Z

72

OOF: Finite Element Analysis of Microstructures - TMS  

Science Conference Proceedings (OSTI)

Feb 7, 2007 ... Topic Title: OOF: Finite Element Analysis of Microstructures ... and the RAM available to perform a simulation spans somewhere between three...

73

Efficient, accurate and flexible finite element solvers for chemotaxis problems  

Science Conference Proceedings (OSTI)

In the framework of finite element discretizations, we introduce a fully nonlinear Newton-like method and a linearized second order approach in time applied to certain partial differential equations for chemotactic processes incorporating two entities, ... Keywords: Chemotaxis model, Finite element, Monolithic, Newton, Nonlinear, Pattern formation

Robert Strehl; Andriy Sokolov; Stefan Turek

2012-08-01T23:59:59.000Z

74

Numerical Modeling of Hydraulic Fracture Propagation Using Thermo-hydro-mechanical Analysis with Brittle Damage Model by Finite Element Method  

E-Print Network (OSTI)

Better understanding and control of crack growth direction during hydraulic fracturing are essential for enhancing productivity of geothermal and petroleum reservoirs. Structural analysis of fracture propagation and impact on fluid flow is a challenging issue because of the complexity of rock properties and physical aspects of rock failure and fracture growth. Realistic interpretation of the complex interactions between rock deformation, fluid flow, heat transfer, and fracture propagation induced by fluid injection is important for fracture network design. In this work, numerical models are developed to simulate rock failure and hydraulic fracture propagation. The influences of rock deformation, fluid flow, and heat transfer on fracturing processes are studied using a coupled thermo-hydro-mechanical (THM) analysis. The models are used to simulate microscopic and macroscopic fracture behaviors of laboratory-scale uniaxial and triaxial experiments on rock using an elastic/brittle damage model considering a stochastic heterogeneity distribution. The constitutive modeling by the energy release rate-based damage evolution allows characterizing brittle rock failure and strength degradation. This approach is then used to simulate the sequential process of heterogeneous rock failures from the initiation of microcracks to the growth of macrocracks. The hydraulic fracturing path, especially for fractures emanating from inclined wellbores and closed natural fractures, often involves mixed mode fracture propagation. Especially, when the fracture is inclined in a 3D stress field, the propagation cannot be modeled using 2D fracture models. Hence, 2D/3D mixed-modes fracture growth from an initially embedded circular crack is studied using the damage mechanics approach implemented in a finite element method. As a practical problem, hydraulic fracturing stimulation often involves fluid pressure change caused by injected fracturing fluid, fluid leakoff, and fracture propagation with brittle rock behavior and stress heterogeneities. In this dissertation, hydraulic fracture propagation is simulated using a coupled fluid flow/diffusion and rock deformation analysis. Later THM analysis is also carried out. The hydraulic forces in extended fractures are solved using a lubrication equation. Using a new moving-boundary element partition methodology (EPM), fracture propagation through heterogeneous media is predicted simply and efficiently. The method allows coupling fluid flow and rock deformation, and fracture propagation using the lubrication equation to solve for the fluid pressure through newly propagating crack paths. Using the proposed model, the 2D/3D hydraulic fracturing simulations are performed to investigate the role of material and rock heterogeneity. Furthermore, in geothermal and petroleum reservoir design, engineers can take advantage of thermal fracturing that occurs when heat transfers between injected flow and the rock matrix to create reservoir permeability. These thermal stresses are calculated using coupled THM analysis and their influence on crack propagation during reservoir stimulation are investigated using damage mechanics and thermal loading algorithms for newly fractured surfaces.

Min, Kyoung

2013-08-01T23:59:59.000Z

75

Generalized finite element method for Helmholtz equation  

E-Print Network (OSTI)

This dissertation presents the Generalized Finite Element Method (GFEM) for the scalar Helmholtz equation, which describes the time harmonic acoustic wave propagation problem. We introduce several handbook functions for the Helmholtz equation, namely the planewave, wave-band, and Vekua functions, and we use these handbook functions to enrich the Finite Element space via the Partition of Unity Method to create the GFEM space. The enrichment of the approximation space by these handbook functions reduces the pollution effect due to wave number and we are able to obtain a highly accurate solution with a much smaller number of degrees-of-freedom compared with the classical Finite Element Method. The q-convergence of the handbook functions is investigated, where q is the order of the handbook function, and it is shown that asymptotically the handbook functions exhibit the same rate of exponential convergence. Hence we can conclude that the selection of the handbook functions from an admissible set should be dictated only by the ease of implementation and computational costs. Another issue addressed in this dissertation is the error coming from the artificial truncation boundary condition, which is necessary to model the Helmholtz problem set in the unbounded domain. We observe that for high q, the most significant component of the error is the one due to the artificial truncation boundary condition. Here we propose a method to assess this error by performing an additional computation on the extended domain using GFEM with high q.

Hidajat, Realino Lulie

2007-05-01T23:59:59.000Z

76

Machining processes simulation: specific finite element aspects  

Science Conference Proceedings (OSTI)

The paper presents a simulation tool designed to predict form errors of part surfaces obtained by face milling and turning processes. For these operations, the form error is often due to the flexibility of the workpiece and its supports. The finite element ... Keywords: finite elements, milling, simulation, turning

Luc Masset; Jean-Francois Debongnie

2004-07-01T23:59:59.000Z

77

Finite element analysis of multilayer coextrusion.  

Science Conference Proceedings (OSTI)

Multilayer coextrusion has become a popular commercial process for producing complex polymeric products from soda bottles to reflective coatings. A numerical model of a multilayer coextrusion process is developed based on a finite element discretization and two different free-surface methods, an arbitrary-Lagrangian-Eulerian (ALE) moving mesh implementation and an Eulerian level set method, to understand the moving boundary problem associated with the polymer-polymer interface. The goal of this work is to have a numerical capability suitable for optimizing and troubleshooting the coextrusion process, circumventing flow instabilities such as ribbing and barring, and reducing variability in layer thickness. Though these instabilities can be both viscous and elastic in nature, for this work a generalized Newtonian description of the fluid is used. Models of varying degrees of complexity are investigated including stability analysis and direct three-dimensional finite element free surface approaches. The results of this work show how critical modeling can be to reduce build test cycles, improve material choices, and guide mold design.

Hopkins, Matthew Morgan; Schunk, Peter Randall; Baer, Thomas A. (Proctor & Gamble Company, West Chester, OH); Mrozek, Randy A. (Army Research Laboratory, Adelphi, MD); Lenhart, Joseph Ludlow (Army Research Laboratory, Adelphi, MD); Rao, Rekha Ranjana; Collins, Robert (Oak Ridge National Laboratory); Mondy, Lisa Ann

2011-09-01T23:59:59.000Z

78

An Adjoint Ocean Model Using Finite Elements: An Application to the South Atlantic  

Science Conference Proceedings (OSTI)

A new inverse model to study the large-scale ocean circulation and its associated heat and freshwater budget is developed. The model relies on traditional assumptions of mass, heat, and salt conservation. A three-dimensional velocity field that ...

Uwe Dobrindt; Jens Schrter

2003-03-01T23:59:59.000Z

79

Inclusion of a TKE Boundary Layer Parameterization in the Canadian Regional Finite-Element Model  

Science Conference Proceedings (OSTI)

The formulation of the regional model recently implemented by the Atmospheric Environment Service of Canada for its operational 48 h NWP forecasts is presented. The emphasis is put on the parameterization of the physical processes, especially ...

R. Benoit; J. Ct; J. Mailhot

1989-08-01T23:59:59.000Z

80

A finite element analysis modeling tool for solid oxide fuel cell development: coupled electrochemistry, thermal and flow analysis in MARC  

Science Conference Proceedings (OSTI)

A 3D simulation tool for modeling solid oxide fuel cells is described. The tool combines the versatility and efficiency of a commercial finite element analysis code, MARC{reg_sign}, with an in-house developed robust and flexible electrochemical (EC) module. Based upon characteristic parameters obtained experimentally and assigned by the user, the EC module calculates the current density distribution, heat generation, and fuel and oxidant species concentration, taking the temperature profile provided by MARC{reg_sign} and operating conditions such as the fuel and oxidant flow rate and the total stack output voltage or current as the input. MARC{reg_sign} performs flow and thermal analyses based on the initial and boundary thermal and flow conditions and the heat generation calculated by the EC module. The main coupling between MARC{reg_sign} and EC is for MARC{reg_sign} to supply the temperature field to EC and for EC to give the heat generation profile to MARC{reg_sign}. The loosely coupled, iterative scheme is advantageous in terms of memory requirement, numerical stability and computational efficiency. The coupling is iterated to self-consistency for a steady-state solution. Sample results for steady states as well as the startup process for stacks with different flow designs are presented to illustrate the modeling capability and numerical performance characteristic of the simulation tool.

Khaleel, Mohammad A.; Lin, Zijing; Singh, Prabhakar; Surdoval, Wayne; Collin, D

2004-05-03T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

An Accurate and Efficient Finite-Element Global Model of the Shallow-Water Equations  

Science Conference Proceedings (OSTI)

In Ct and Staniforth the efficiency of a semi-implicit spectral model of the shallow-water primitive equations was significantly improved by replacing the usual three-time-level Eulerian treatment of advection by a two-time-level semi-...

Jean Ct; Andrew Staniforth

1990-12-01T23:59:59.000Z

82

A finite element model for hygro-thermo-mechanical analysis of masonry walls with FRP reinforcement  

Science Conference Proceedings (OSTI)

Modeling the effects of humidity and temperature gradients on the structural behavior of masonry walls reinforced with fiber reinforced polymer (FRP) composite is of great importance. Study of interfacial stresses, in particular, is a key factor in predicting ... Keywords: FRP reinforced masonry, Moisture and temperature, Multi-layered permeable structure, Structural analysis

Mehran Khoshbakht; Mark W. Lin

2010-10-01T23:59:59.000Z

83

Materials Reliability Program: Finite-Element Model Validation for Dissimilar Metal Butt-Welds (MRP-316)  

Science Conference Proceedings (OSTI)

Residual stresses imparted by the welding process are a principal factor in the process of primary water stress corrosion cracking (PWSCC) of Alloy 82/182 nickel-alloy dissimilar metal (DM) piping butt welds in pressurized water reactors (PWRs). Analytical models are frequently used to simulate the welding process in order to predict the residual stress distribution in the weld and base material as an input to crack growth calculations. The crack growth calculations, in turn, have demonstrated a high sen...

2011-12-20T23:59:59.000Z

84

Solid Mechanics/Finite-Element Analysis Software/Codes - TMS  

Science Conference Proceedings (OSTI)

CalculiX - A Free Software Three-Dimensional Structural Finite Element Program G. Dhondt and K. Wittig. Open Source (GPL) 3-D Finite Element Mechanics...

85

Materials Reliability Program: Welding Residual Stress Dissimilar Metal Butt-Weld Finite Element Modeling Handbook (MRP-317)  

Science Conference Proceedings (OSTI)

The residual stresses imparted by the welding process are a principal factor in the process of primary water stress corrosion cracking (PWSCC) of Alloy 82/182 nickel-alloy (i.e., dissimilar metal) piping butt welds in pressurized water reactors (PWRs). Numerical methods by finite element analyses are frequently used to simulate the welding process in order to predict the residual stress distribution in the weld and base material as an input to crack growth calculations. The crack growth calculations, in ...

2011-12-22T23:59:59.000Z

86

ME 452 Finite Element Analysis Every Semester  

E-Print Network (OSTI)

ME 452 Finite Element Analysis Elective Every Semester 2004-2005 Catalog Data: Conversion. Extensive computer lab experiments using Matlab-based and commercial software systems. Prereq: ME 321, 344 of proper boundary conditions and nodal loads. 6. Conversion of distributed loads to work equivalent nodal

Mench, Matthew M.

87

Rotation capacity of partial strength steel joints with three-dimensional finite element approach  

Science Conference Proceedings (OSTI)

This paper presents a finite element analysis of partial strength steel joints. The joint configurations are drawn from a previous experimental study, with good prediction shown by the finite element model. Failure of the joint is confined to the end ... Keywords: Ductile fracture, Finite element, Structural joint

Ana M. GirO Coelho

2013-01-01T23:59:59.000Z

88

Modeling the steady-state ISV (in situ vitrification) process: A 3-D finite element analysis of coupled thermal-electric fields  

Science Conference Proceedings (OSTI)

Steady-state modeling considerations for simulating the in situ vitrification (ISV) process are documented based upon the finite element numerical approach. Recommendations regarding boundary condition specifications and mesh discretization are presented. The effects of several parameters on the ISV process response are calculated and the results discussed. The parameters investigated include: (1) electrode depth, (2) ambient temperature, (3) supplied current, (4) electrical conductivity, (5) electrode separation, and (6) soil/waste characterization. 13 refs., 29 figs., 1 tab.

Langerman, M.A.

1990-09-01T23:59:59.000Z

89

Finite element analysis of laterally loaded fin piles  

Science Conference Proceedings (OSTI)

A three-dimensional analysis of laterally loaded fin piles is presented. The behaviour of fin piles is difficult to explain using simple pile-soil theories or two dimensional numerical analyses because of the complicated geometry of the piles. In this ... Keywords: 3D finite element models, Capacity of laterally loaded piles, Efficiency of fins, Fin piles, Mohr-Coulomb soil model, Monopiles

J. -R. Peng; M. Rouainia; B. G. Clarke

2010-11-01T23:59:59.000Z

90

A Finite-Element Model of the Atmospheric Boundary Layer Suitable for Use with Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

We give a detailed description of an atmospheric boundary layer model capable of simulating the diurnal cycles of wind, temperature and humidity. The model includes a formulation of various physical processes (radiative effects, variation of soil ...

J. Mailhot; R. Benoit

1982-10-01T23:59:59.000Z

91

FEHM (Finite Element Heat and Mass Transfer Code)  

NLE Websites -- All DOE Office Websites (Extended Search)

FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep...

92

A Nonhydrostatic Finite-Element Model for Three-Dimensional Stratified Oceanic Flows. Part I: Model Formulation  

Science Conference Proceedings (OSTI)

The vast majority of advanced numerical ocean models in use today, while performing extremely well, especially for certain classes of problem, do not necessarily take full advantage of current trends in numerical analysis and scientific ...

R. Ford; C. C. Pain; M. D. Piggott; A. J. H. Goddard; C. R. E. de Oliveira; A. P. Umpleby

2004-12-01T23:59:59.000Z

93

Finite element modeling of Cr(VI) reduction by Shewanella oneidensis MR-1 employing the dual-enzyme kinetic model  

Science Conference Proceedings (OSTI)

Chromium (VI) (Cr(VI)) contamination of soil and groundwater is considered a major environmental concern. Bioreduction of Cr(VI) to chromium (III) (Cr(III)) can be considered an effective technology in remediating Cr(VI) contaminated sites. Among the ... Keywords: Bioreduction, Cr(VI), Dual-enzyme, Modeling

Md. Akram Hossain; Mahbub Alam; David Yonge; Prashanta Dutta

2005-12-01T23:59:59.000Z

94

An h-Adaptive Finite-Element Technique for Constructing 3D Wind Fields  

Science Conference Proceedings (OSTI)

An h-adaptive, mass-consistent finite-element model (FEM) has been developed for constructing 3D wind fields over irregular terrain utilizing sparse meteorological tower data. The element size in the computational domain is dynamically controlled ...

Darrell W. Pepper; Xiuling Wang

2009-03-01T23:59:59.000Z

95

B-spline finite elements for plane elasticity problems.  

E-Print Network (OSTI)

??The finite element method since its development in the 1950â??s has been used extensively in solving complex problems involving partial differential equations. The conventional finite (more)

Aggarwal, Bhavya

2007-01-01T23:59:59.000Z

96

FEHM: finite element heat and mass transfer code  

DOE Green Energy (OSTI)

The finite element heat and mass (FEHM) transfer code is a computer code developed to simulate geothermal and hot dry rock reservoirs. It is also applicable to natural-state studies of geothermal systems and ground-water flow. It solves the equations of heat and mass transfer for multiphase flow in porous and permeable media using the finite element method. The code also has provisions for a noncoupled tracer; that is, the tracer solutions do not affect the heat and mass transfer solutions. It can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model, the numerical solution procedure, and model verification and validation are provided in this report. A user's guide and sample problems are included in the appendices. 17 refs., 10 figs., 4 tabs.

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1988-03-01T23:59:59.000Z

97

A Drift-Diffusion-Reaction Model for Excitonic Photovoltaic Bilayers: Asymptotic Analysis and A 2-D HDG Finite-Element Scheme  

E-Print Network (OSTI)

We present and discuss a mathematical model for the operation of bilayer organic photovoltaic devices. Our model couples drift-diffusion-recombination equations for the charge carriers (specifically, electrons and holes) with a reaction-diffusion equation for the excitons/ polaron pairs and Poisson's equation for the self-consistent electrostatic potential. The material difference (i.e. the HOMO/LUMO gap) of the two organic substrates forming the bilayer device are included as a work-function potential. Firstly, we perform an asymptotic analysis of the scaled one-dimensional stationary state system i) with focus on the dynamics on the interface and ii) with the goal of simplifying the bulk dynamics away for the interface. Secondly, we present a twodimensional Hybrid Discontinuous Galerkin Finite Element numerical scheme which is very well suited to resolve i) the material changes ii) the resulting strong variation over the interface and iii) the necessary upwinding in the discretization of drift-diffusion equ...

Brinkman, Daniel; Markowich, Peter A; Wolfram, Marie-Therese

2012-01-01T23:59:59.000Z

98

Finite Element Analysis of Erosion for Offshore Structure  

Science Conference Proceedings (OSTI)

Presentation Title, Finite Element Analysis of Erosion for Offshore Structure ... impacting, is one of the major failure modes that cause offshore structure damage .

99

OOF: Finite Element Analysis of Microstructures, OOF2 - TMS  

Science Conference Proceedings (OSTI)

May 8, 2007 ... Topic Title: OOF: Finite Element Analysis of Microstructures, OOF2 ... and the RAM available to perform a simulation spans somewhere...

100

A finite element approach for multiphase fluid flow in porous media  

Science Conference Proceedings (OSTI)

The main scope of this work is to carry out a mathematical framework and its corresponding finite element (FE) discretization for the partially saturated soil consolidation modelling in presence of an immiscible pollutant. A multiphase system with the ... Keywords: Consolidation, Finite elements, Immiscible pollutants, Mixture theory, Multiphase porous media

Javier L. Mroginski; H.Ariel Di Rado; Pablo A. Beneyto; Armando M. Awruch

2010-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

A fully coupled finite element model of coal deformation and two phase flow for coalbed methane extraction.  

E-Print Network (OSTI)

??A reservoir simulation model is usually required to represent the combined effects of gas transport, water flow, and coal swelling/shrinking on the extraction of coalbed (more)

Chen, Dong

2012-01-01T23:59:59.000Z

102

Summary of the Models and Methods for the FEHM Application-A Finite-Element Heat- and Mass-Transfer Code  

DOE Green Energy (OSTI)

The mathematical models and numerical methods employed by the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multi-component flow in porous media, are described. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The component models of FEHM are discussed. The first major component, Flow- and Energy-Transport Equations, deals with heat conduction; heat and mass transfer with pressure- and temperature-dependent properties, relative permeabilities and capillary pressures; isothermal air-water transport; and heat and mass transfer with noncondensible gas. The second component, Dual-Porosity and Double-Porosity/Double-Permeability Formulation, is designed for problems dominated by fracture flow. Another component, The Solute-Transport Models, includes both a reactive-transport model that simulates transport of multiple solutes with chemical reaction and a particle-tracking model. Finally, the component, Constitutive Relationships, deals with pressure- and temperature-dependent fluid/air/gas properties, relative permeabilities and capillary pressures, stress dependencies, and reactive and sorbing solutes. Each of these components is discussed in detail, including purpose, assumptions and limitations, derivation, applications, numerical method type, derivation of numerical model, location in the FEHM code flow, numerical stability and accuracy, and alternative approaches to modeling the component.

George A. Zyvoloski; Bruce A. Robinson; Zora V. Dash; Lynn L. Trease

1997-07-01T23:59:59.000Z

103

A Direct Inverse Method for Inferring Open Boundary Conditions of a Finite-Element Linear Harmonic Ocean Circulation Model  

Science Conference Proceedings (OSTI)

A direct inverse method is presented for inferring numerical model open boundary conditions from interior observational data. The dynamical context of the method is the frequency-domain 3D linear shallow water equations. A set of weight matrices ...

Zhigang Xu

1998-12-01T23:59:59.000Z

104

The impact of parallel programming models on the performance of iterative linear solvers for finite element applications  

Science Conference Proceedings (OSTI)

Parallel iterative linear solvers for unstructured grids in FEM applications, originally developed for the Earth Simulator (ES), are ported to various types of parallel computer. The performance of flat MPI and hybrid parallel programming models is compared ...

Kengo Nakajima

2006-06-01T23:59:59.000Z

105

Finite element method for conserved phase fields: Stress-mediated diffusional phase transformation  

Science Conference Proceedings (OSTI)

Phase-field models with conserved phase-field variables result in a 4th order evolution partial differential equation (PDE). When coupled with the usual 2nd order thermo-mechanics equations, such problems require special treatment. In the past, the finite ... Keywords: Binary alloys, Convergence, Galerkin finite element method, Phase-field model

Mohsen Asle Zaeem; Sinisa Dj. Mesarovic

2010-12-01T23:59:59.000Z

106

A Variable-Resolution Semi-Lagrangian Finite-Element Global Model of the Shallow-Water Equations  

Science Conference Proceedings (OSTI)

To meet the needs of short- and medium-range operational forecasting, the authors propose a unified strategy based on the use of a global variable-resolution model, run in two different configurations. These are as follows: (i) a variable-...

Jean Ct; Michel Roch; Andrew Staniforth; Luc Fillion

1993-01-01T23:59:59.000Z

107

Tracer Conservation for Three-Dimensional, Finite-Element, Free-Surface, Ocean Modeling on Moving Prismatic Meshes  

Science Conference Proceedings (OSTI)

Large-scale free-surface ocean models designed to run over climatic time scales are required to globally conserve the volume and any tracer up to machine precision. In addition, local consistency is critical and requires that the discrete tracer ...

Laurent White; Vincent Legat; Eric Deleersnijder

2008-02-01T23:59:59.000Z

108

Finite-Element Solutions of Free-Interface Density Currents  

Science Conference Proceedings (OSTI)

An interface-adaptive finite-element iteration scheme is designed to solve for the free interface of an inviscid steady-state density current. The method is also applied to free-surface flows over finite obstacles, but convergent solutions are ...

Qin Xu; Fu-Shen Zhang; Guang-Ping Lou

1992-01-01T23:59:59.000Z

109

FEHM (Finite Element Heat and Mass Transfer Code)  

NLE Websites -- All DOE Office Websites (Extended Search)

FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. June 29, 2013 software FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. Available for thumbnail of Feynman Center (505) 665-9090 Email FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. FEHM has proved to be a valuable asset on a variety of

110

Iterative solutions to large sparse finite element equations  

E-Print Network (OSTI)

Iterative methods are widely used to solve sparse linear systems due to the improvements which can be achieved in reducing the solution time and increasing the size of the problem which can be solved on a given computer compared to traditional direct solvers. The theory behind the convergence rate relationship and storage requirements for the preconditioned conjugate gradient methods using the diagonal scaling, incomplete Cholesky decomposition and SSOR preconditioners is explained in detail in this study. Sparse matrix storage techniques, such as profile, element-by-element, and compact row storage, are described along with the redefined matrix operations for each storage technique which must be used to eliminate the operations on zero elements. A procedure to directly assemble the global stiffness in compact row storage format from element stiffness matrices is introduced. Numerical studies have been performed to compare the storage requirements, the convergence rate, and the solution time for the direct and PCG methods using various storage formats. Effects of different material properties and external loading on the convergence rate and solution time are also analyzed. The test problems for this study are based on the three-dimensional linear elasticity finite element equations. The physical memory of 64 MB of RAM of the IBM RISC/6000 Model 355 workstation was the limiting factor for the size of the sparse linear system that could be solved in this study. The diagonal preconditioned conjugate gradient method with the compact row storage has solved a three-dimensional finite element problem up to a maximum of 50,000 equations on an IBM RISC/6000 Model 355 workstation with 64 MB of RAM. To apply adaptive mesh refinement on certain regions of a coarse mesh, the modeling error over a coarse mesh must be estimated. This thesis will show that the modeling error from an intermediate unconverged coarse mesh solution will closely match the modeling error from the converged solution. This result may lead to quicker solution times for a highly accurate mesh based on adaptive mesh refinement iterative methods.

Wang, Hongbing

1995-01-01T23:59:59.000Z

111

Implementation of B-splines in a Conventional Finite Element Framework  

E-Print Network (OSTI)

The use of B-spline interpolation functions in the finite element method (FEM) is not a new subject. B-splines have been utilized in finite elements for many reasons. One reason is the higher continuity of derivatives and smoothness of B-splines. Another reason is the possibility of reducing the required number of degrees of freedom compared to a conventional finite element analysis. Furthermore, if B-splines are utilized to represent the geometry of a finite element model, interfacing a finite element analysis program with existing computer aided design programs (which make extensive use of B-splines) is possible. While B-splines have been used in finite element analysis due to the aforementioned goals, it is difficult to find resources that describe the process of implementing B-splines into an existing finite element framework. Therefore, it is necessary to document this methodology. This implementation should conform to the structure of conventional finite elements and only require exceptions in methodology where absolutely necessary. One goal is to implement B-spline interpolation functions in a finite element framework such that it appears very similar to conventional finite elements and is easily understandable by those with a finite element background. The use of B-spline functions in finite element analysis has been studied for advantages and disadvantages. Two-dimensional B-spline and standard FEM have been compared. This comparison has addressed the accuracy as well as the computational efficiency of B-spline FEM. Results show that for a given number of degrees of freedom, B-spline FEM can produce solutions with lower error than standard FEM. Furthermore, for a given solution time and total analysis time B-spline FEM will typically produce solutions with lower error than standard FEM. However, due to a more coupled system of equations and larger elemental stiffness matrix, B-spline FEM will take longer per degree of freedom for solution and assembly times than standard FEM. Three-dimensional B-spline FEM has also been validated by the comparison of a three-dimensional model with plane-strain boundary conditions to an equivalent two-dimensional model using plane strain conditions.

Owens, Brian C.

2009-05-01T23:59:59.000Z

112

A displacement-based nonlinear finite element formulation using meshfree-enriched triangular elements for the two-dimensional large deformation analysis of elastomers  

Science Conference Proceedings (OSTI)

In this paper a displacement-based meshfree-enriched finite element method, which was proposed for the linear modeling of near-incompressible elasticity, is generalized for the nonlinear analysis of elastomers. A four-noded triangular element based on ... Keywords: Elastomers, Finite element, Meshfree, Near-incompressible, Nonlinear

W. Hu; C. T. Wu; M. Koishi

2012-03-01T23:59:59.000Z

113

Computer Based Training: Engineering Technical Training Modules - Finite Element Analysis v1.0  

Science Conference Proceedings (OSTI)

Finite Element Analysis ETTM, Version 1.0 is a computer45based training module that allows users to access training when desired and review it at their own pace. This module provides information about the basics of finite element analysis and modeling. This training should be used for position specific and/or continuing training for individuals involved with finite element analysis. This computer-based training (CBT) module is intended for use by new engineers as well as engineers changing jobs where bas...

2009-12-01T23:59:59.000Z

114

The Uranium Processing Facility Finite Element Meshing Discussion  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Uranium Processing Facility (UPF) Uranium Processing Facility (UPF) Finite Element Meshing Discussion ...Need picture of Building... October 25, 2011 Department of Energy - Natural Phenomenon Hazard Workshop 1 Loring Wyllie Arne Halterman Degenkolb Engineers, San Francisco Purpose of Presentation * Design vs. Analysis * Discuss the mesh criteria * Discuss the evolution of the mesh of the UPF main building model * Discuss how the mesh affects the analysis process October 25, 2011 2 Department of Energy - Natural Phenomenon Hazard Workshop FEM Modeling * GTStrudl typically used for DOE projects. * Mesh size is important * What is to be captured? * How complex is the system? * Current criteria set to capture in-plane and out-of-plane response. October 25, 2011 3

115

Influence of p-method finite element parameters on predictions of crack front geometry  

Science Conference Proceedings (OSTI)

The effect of various p-method finite element model parameters on the prediction of planar crack front geometry in three dimensional structures is evaluated. An automatic crack growth method was developed using the commercial software StressCheck coupled ... Keywords: ?, Corner crack, Crack front, Finite element, Mesh, Stress intensity factor, a, b, b/a, c, ctrat, ipr, m, mrat, p-method, trans

Diane Wowk, Kyle Gamble, Ross Underhill

2013-10-01T23:59:59.000Z

116

Experimental and finite element analysis of high pressure packer elements  

E-Print Network (OSTI)

Packer elements are traditionally rubber seals that can operate under specified downhole conditions and provide a seal for either a short-term, retrievable, or a long-term, permanent, completion. In this case a retrievable ...

Berger, Stephanie, 1981-

2004-01-01T23:59:59.000Z

117

Solar Electric Generating System II finite element analysis  

DOE Green Energy (OSTI)

On June 2, 1992, Landers` earthquake struck the Solar Electric Generating System II, located in Daggett, California. The 30 megawatt power station, operated by the Daggett Leasing Corporation (DLC), suffered substantial damage due to structural failures in the solar farm. These failures consisted of the separation of sliding joints supporting a distribution of parabolic glass mirrors. At separation, the mirrors fell to the ground and broke. It was the desire of the DLC and the Solar Thermal Design Assistance Center (STDAC) of Sandia National Laboratories (SNL) and to redesign these joints so that, in the event of future quakes, costly breakage will be avoided. To accomplish this task, drawings of collector components were developed by the STDAC, from which a detailed finite element computer model of a solar collector was produced. This nonlinear dynamic model, which consisted of over 8,560 degrees of freedom, underwent model reduction to form a low order nonlinear dynamic model containing only 40 degrees of freedom. This model was then used as a design tool to estimate joint dynamics. Using this design tool, joint configurations were modified, and an acceptable joint redesign determined. The results of this analysis showed that the implementation of metal stops welded to support shafts for the purpose of preventing joint separation is a suitable joint redesign. Moreover, it was found that, for quakes of Landers` magnitude, mirror breakage due to enhanced vibration in the trough assembly is unlikely.

Dohner, J.L.; Anderson, J.R.

1994-04-01T23:59:59.000Z

118

Estimating local thickness for finite element analysis  

Science Conference Proceedings (OSTI)

Within the development of motor vehicles, crash safety is one of the most important attributes. To comply with the ever increasing requirements of shorter cycle times and costs reduction, car manufacturers keep intensifying the use of virtual development ... Keywords: FEA mesh, automotive crash simulations, ray tracing, structural modelling, thickness estimation

Vnio Ferreira; Lus Paulo Santos; Ricardo Simoes; Markus Franzen; Omar O. Ghouati

2010-11-01T23:59:59.000Z

119

Finite element form of FDV for widely varying flowfields  

Science Conference Proceedings (OSTI)

We present the Flowfield Dependent Variation (FDV) method for physical applications that have widely varying spatial and temporal scales. Our motivation is to develop a versatile numerical method that is accurate and stable in simulations with complex ... Keywords: Finite element, Hydrodynamics, Numerical methods, Shock waves, Special relativity

G. A. Richardson; J. T. Cassibry; T. J. Chung; S. T. Wu

2010-01-01T23:59:59.000Z

120

BOR-FDTD subgridding based on finite element principles  

Science Conference Proceedings (OSTI)

In this paper a recently developed provably passive and stable 3D FDTD subgridding technique, based on finite elements principles, is extended to body-of-revolution (BOR) FDTD. First, a suitable choice of basis functions is presented together with the ... Keywords: BOR-FDTD, Body-of-revolution, FDTD methods, Subgridding, h-Refinement

Wouter Tierens; Danil De Zutter

2011-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Fuzzy and interval finite element method for heat conduction problem  

E-Print Network (OSTI)

Traditional finite element method is a well-established method to solve various problems of science and engineering. Different authors have used various methods to solve governing differential equation of heat conduction problem. In this study, heat conduction in a circular rod has been considered which is made up of two different materials viz. aluminum and copper. In earlier studies parameters in the differential equation have been taken as fixed (crisp) numbers which actually may not. Those parameters are found in general by some measurements or experiments. So the material properties are actually uncertain and may be considered to vary in an interval or as fuzzy and in that case complex interval arithmetic or fuzzy arithmetic has to be considered in the analysis. As such the problem is discretized into finite number of elements which depend on interval/fuzzy parameters. Representation of interval/fuzzy numbers may give the clear picture of uncertainty. Hence interval/fuzzy arithmetic is applied in the finite element method to solve a steady state heat conduction problem. Application of fuzzy finite element method in the said problem gives fuzzy system of linear equations in general. Here new methods have also been proposed to handle such type of fuzzy system of linear equations. Corresponding results are computed and has been reported here.

Sarangam Majumdar; Sukanta Nayak; S. Chakraverty

2012-09-26T23:59:59.000Z

122

Finite element analysis of the electro jet drilling process  

Science Conference Proceedings (OSTI)

The electro jet drilling (EJD) process is gaining prominence in the machining of micro and macro holes in difficult-to-machine materials used in aerospace, electronics and computers, medical, and automobile industries. As the trend towards miniaturization ... Keywords: electro jet drilling, electrochemical drilling, finite element method, radial overcut

M. Sen; H. S. Shan

2007-01-01T23:59:59.000Z

123

A hybrid-mixed finite element formulation for the geometrically exact analysis of three-dimensional framed structures  

Science Conference Proceedings (OSTI)

This paper addresses the development of a hybrid-mixed finite element formulation for the quasi-static geometrically exact analysis of three-dimensional framed structures with linear elastic behavior. The formulation is based on a modified principle ... Keywords: Complementary energy principle, Geometrically exact analysis, Hybrid-mixed finite elements, One-dimensional beam model, Three-dimensional framed structures

H. A. Santos; P. M. Pimenta; J. P. Almeida

2011-11-01T23:59:59.000Z

124

A finite element simulation of biological conversion processes in landfills  

Science Conference Proceedings (OSTI)

Landfills are the most common way of waste disposal worldwide. Biological processes convert the organic material into an environmentally harmful landfill gas, which has an impact on the greenhouse effect. After the depositing of waste has been stopped, current conversion processes continue and emissions last for several decades and even up to 100 years and longer. A good prediction of these processes is of high importance for landfill operators as well as for authorities, but suitable models for a realistic description of landfill processes are rather poor. In order to take the strong coupled conversion processes into account, a constitutive three-dimensional model based on the multiphase Theory of Porous Media (TPM) has been developed at the University of Duisburg-Essen. The theoretical formulations are implemented in the finite element code FEAP. With the presented calculation concept we are able to simulate the coupled processes that occur in an actual landfill. The model's theoretical background and the results of the simulations as well as the meantime successfully performed simulation of a real landfill body will be shown in the following.

Robeck, M., E-mail: markus.robeck@uni-due.de [Department of Water and Waste Management, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany); Ricken, T. [Institute of Mechanics/Computational Mechanics, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany); Widmann, R. [Department of Water and Waste Management, Building Sciences, University of Duisburg-Essen, Universitaetsstrasse 15, 45141 Essen (Germany)

2011-04-15T23:59:59.000Z

125

Finite size scaling for quantum criticality using the finite-element method  

E-Print Network (OSTI)

Finite size scaling for the Schr\\"{o}dinger equation is a systematic approach to calculate the quantum critical parameters for a given Hamiltonian. This approach has been shown to give very accurate results for critical parameters by using a systematic expansion with global basis-type functions. Recently, the finite element method was shown to be a powerful numerical method for ab initio electronic structure calculations with a variable real-space resolution. In this work, we demonstrate how to obtain quantum critical parameters by combining the finite element method (FEM) with finite size scaling (FSS) using different ab initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, internuclear distances, electron density, disorder, lattice structure, and external fields for stability of atomic, molecular systems and quantum phase transitions of extended systems. To illustrate the effectiveness of this approach we provide detailed calculations of applying FEM to approximate solutions for the two-electron atom with varying nuclear charge; these include Hartree-Fock, density functional theory under the local density approximation, and an "exact"' formulation using FEM. We then use the FSS approach to determine its critical nuclear charge for stability; here, the size of the system is related to the number of elements used in the calculations. Results prove to be in good agreement with previous Slater-basis set calculations and demonstrate that it is possible to combine finite size scaling with the finite-element method by using ab initio calculations to obtain quantum critical parameters. The combined approach provides a promising first-principles approach to describe quantum phase transitions for materials and extended systems.

Edwin Antillon; Birgit Wehefritz-Kaufmann; Sabre Kais

2011-09-12T23:59:59.000Z

126

Error Estimates for a Combined Finite Volume--Finite Element Method for Nonlinear Convection--Diffusion Problems  

Science Conference Proceedings (OSTI)

The subject of this paper is the analysis of error estimates of the combined finite volume--finite element (FV--FE) method for the numerical solution of a scalar nonlinear conservation law equation with a diffusion term. Nonlinear convective terms are ... Keywords: a priori estimates, compressible Navier--Stokes equations, discrete maximum principle, error estimates, finite element method, monotone finite volume schemes, nonlinear convection-diffusion equation, numerical integration

Miloslav Feistauer; Jir Felcman; Mria Lukcov-Medvidov; Gerald Warnecke

1999-07-01T23:59:59.000Z

127

Finite element analysis of contact stress in a full-metallic pipe joint for hydrogen pipelines  

Science Conference Proceedings (OSTI)

Hydrogen gas has been widely recognized as an environmentally clean and renewable energy fuel, and it provides a way to reduce greenhouse gas and air pollution emission. A great deal of effort has been made to develop new techniques in the field of hydrogen ... Keywords: contact stress analyses, finite element model (FEM), hydrogen pipelines, metallic gasket, pipe joint

Nan Bu; Naohiro Ueno; Osamu Fukuda

2010-02-01T23:59:59.000Z

128

Adjacency-based data reordering algorithm for acceleration of finite element computations  

Science Conference Proceedings (OSTI)

Effective use of the processor memory hierarchy is an important issue in high performance computing. In this work, a part level mesh topological traversal algorithm is used to define a reordering of both mesh vertices and regions that increases the spatial ... Keywords: Data reordering, cache penalty model, finite element analysis, unstructured mesh

Min Zhou; Onkar Sahni; Mark S. Shephard; Christopher D. Carothers; Kenneth E. Jansen

2010-04-01T23:59:59.000Z

129

FES99: A Global Tide Finite Element Solution Assimilating Tide Gauge and Altimetric Information  

Science Conference Proceedings (OSTI)

An improved version of the global hydrodynamic tide solutions [finite element solutions (FESs) FES94, FES95.2.1, and FES98] has been developed, implemented, and validated. The new model is based on the resolution of the tidal barotropic equations ...

F. Lefvre; F. H. Lyard; C. Le Provost; E. J. O. Schrama

2002-09-01T23:59:59.000Z

130

A new procedure for the construction of hierarchical high order Hdiv and Hcurl finite element spaces  

Science Conference Proceedings (OSTI)

This paper considers a systematic procedure for the construction of a hierarchy of high order finite element approximation for Hdiv and Hcurl spaces based on triangular and quadrilateral partitions of bidimensional domains. The principle is to choose ... Keywords: Hdiv approximating spaces, Hierarchical finite element bases, Mixed finite element formulations

Denise De Siqueira; Phillipe R. B. Devloo; SNia M. Gomes

2013-03-01T23:59:59.000Z

131

Operator-splitting finite element algorithms for computations of high-dimensional parabolic problems  

E-Print Network (OSTI)

Operator-splitting finite element algorithms for computations of high-dimensional parabolic t i c l e i n f o Keywords: Operator-splitting method Finite element method Parabolic equations High-dimensional problems a b s t r a c t An operator-splitting finite element method for solving high-dimensional parabolic

Ganesan, Sashikumaar

132

An adaptive finite element method for simulating surface tension with the gradient theory of fluid interfaces  

Science Conference Proceedings (OSTI)

The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method ... Keywords: 49S05, 65N30, 65N50, Adaptive finite element method, Gradient theory, Surface tension

Jisheng Kou, Shuyu Sun

2014-01-01T23:59:59.000Z

133

Adaptive nearest-nodes finite element method guided by gradient of linear strain energy density  

Science Conference Proceedings (OSTI)

In this paper, an adaptive finite element method is formulated based on the newly developed nearest-nodes finite element method (NN-FEM). In the adaptive NN-FEM, mesh modification is guided by the gradient of strain energy density, i.e., a larger gradient ... Keywords: Gradient of strain energy density, Mesh intensity, Mesh modification operator, Nearest-nodes finite element method

Yunhua Luo

2009-10-01T23:59:59.000Z

134

Conditions for the invertibility of the isoparametric mapping for hexahedral finite elements  

Science Conference Proceedings (OSTI)

We consider the isoparametric mapping, which maps a given reference element onto a global element given by its vertices, for trilinear finite elements on hexahedra. We present an algorithm that checks the positivity of the Jacobian determinant depending ... Keywords: hexahedral finite elements, invertibility, isoparametric mapping

P. Knabner; S. Korotov; G. Summ

2003-12-01T23:59:59.000Z

135

2D simulation of fluid-structure interaction using finite element method  

Science Conference Proceedings (OSTI)

This paper deals with pressure-based finite element analysis of fluid-structure systems considering the coupled fluid and structural dynamics. The present method uses two-dimensional fluid elements and structural line elements for the numerical simulation ... Keywords: Finite element, Galerkin weighted residual method, Newmark's predictor-corrector method, Pressure formulation, Sloshing

S. Mitra; K. P. Sinhamahapatra

2008-12-01T23:59:59.000Z

136

FINITE ELEMENT ANALYSIS OF BULK TRITIUM SHIPPING PACKAGE  

SciTech Connect

The Bulk Tritium Shipping Package was designed by Savannah River National Laboratory. This package will be used to transport tritium. As part of the requirements for certification, the package must be shown to meet the scenarios of the Hypothetical Accident Conditions (HAC) defined in Code of Federal Regulations Title 10 Part 71 (10CFR71). The conditions include a sequential 30-foot drop event, 30-foot dynamic crush event, and a 40-inch puncture event. Finite Element analyses were performed to support and expand upon prototype testing. Cases similar to the tests were evaluated. Additional temperatures and orientations were also examined to determine their impact on the results. The peak stress on the package was shown to be acceptable. In addition, the strain on the outer drum as well as the inner containment boundary was shown to be acceptable. In conjunction with the prototype tests, the package was shown to meet its confinement requirements.

Jordan, J.

2010-06-02T23:59:59.000Z

137

The Mimetic Finite Element Method and the Virtual Element Method for elliptic problems with arbitrary regularity.  

SciTech Connect

We develop and analyze a new family of virtual element methods on unstructured polygonal meshes for the diffusion problem in primal form, that use arbitrarily regular discrete spaces V{sub h} {contained_in} C{sup {alpha}} {element_of} N. The degrees of freedom are (a) solution and derivative values of various degree at suitable nodes and (b) solution moments inside polygons. The convergence of the method is proven theoretically and an optimal error estimate is derived. The connection with the Mimetic Finite Difference method is also discussed. Numerical experiments confirm the convergence rate that is expected from the theory.

Manzini, Gianmarco [Los Alamos National Laboratory

2012-07-13T23:59:59.000Z

138

Generalized Multiscale Finite Element Methods (GMsFEM)  

E-Print Network (OSTI)

In this paper, we propose a general approach called Generalized Multiscale Finite Element Method (GMsFEM) for performing multiscale simulations for problems without scale separation over a complex input space. As in multiscale finite element methods (MsFEMs), the main idea of the proposed approach is to construct a small dimensional local solution space that can be used to generate an efficient and accurate approximation to the multiscale solution with a potentially high dimensional input parameter space. In the proposed approach, we present a general procedure to construct the offline space that is used for a systematic enrichment of the coarse solution space in the online stage. The enrichment in the online stage is performed based on a spectral decomposition of the offline space. In the online stage, for any input parameter, a multiscale space is constructed to solve the global problem on a coarse grid. The online space is constructed via a spectral decomposition of the offline space and by choosing the eigenvectors corresponding to the largest eigenvalues. The computational saving is due to the fact that the construction of the online multiscale space for any input parameter is fast and this space can be reused for solving the forward problem with any forcing and boundary condition. Compared with the other approaches where global snapshots are used, the local approach that we present in this paper allows us to eliminate unnecessary degrees of freedom on a coarse-grid level. We present various examples in the paper and some numerical results to demonstrate the effectiveness of our method. 1

Yalchin Efendiev; Juan Galvis; Thomas Y. Hou

2013-01-01T23:59:59.000Z

139

Rossby Wave Frequencies and Group Velocities for Finite Element and Finite Difference Approximations to the Vorticity-Divergence and the Primitive Forms of the Shallow Water Equations  

Science Conference Proceedings (OSTI)

In this paper Rossby wave frequencies and group velocities are analyzed for various finite element and finite difference approximations to the vorticity-divergence form of the shallow water equations. Also included are finite difference solutions ...

Beny Neta; R. T. Williams

1989-07-01T23:59:59.000Z

140

Development of A-LITE Model for Use in ATTILA Radiation Transport Finite Element Analysis of the ITER Lower Divertor Region  

Science Conference Proceedings (OSTI)

Computational Tools, Modeling & Validation / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 2)

Aaron T. Aoyama; Mohamad Dagher; Russell Feder; Michael Duco; Mahmoud Youssef

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

The simulation with the finite element method of the velocity and temperature fields for a nonturbionar jet burner of 35MW feeding with pulverized coal  

Science Conference Proceedings (OSTI)

This paper presents the analysis of coal particle combustion in nonturbionar jet burner of 35MW used the Finite Element Method made with aid of the FLUENT programme. The pulverized coal combustion simulation involves modeling a continuous gas phase flow ... Keywords: FLUENT, coal-air mixture, combustion, finite element method, injection coal, nonturbionar jet

Mihai D. L. Talu; Stefan D. L. Talu; Mihai Negru

2007-07-01T23:59:59.000Z

142

Global Superconvergence and A Posteriori Error Estimators of the Finite Element Method for a Quasi-linear Elliptic Boundary Value Problem of Nonmonotone Type  

Science Conference Proceedings (OSTI)

In this paper we are concerned with finite element approximations to a nonlinear elliptic partial differential equation with homogeneous Dirichlet boundary conditions. This kind of problems arises for example from modeling a stationary heat conduction ... Keywords: a posteriori error estimators, anisotropic heat conduction, finite elements, global superconvergence, nonlinear boundary problem, supercloseness

Liping Liu; Tang Liu; Michal Krzek; Tao Lin; Shuhua Zhang

2004-04-01T23:59:59.000Z

143

FEHMN 1.0: Finite element heat and mass transfer code; Revision 1  

Science Conference Proceedings (OSTI)

A computer code is described which can simulate non-isothermal multi-phase multicomponent flow in porous media. It is applicable to natural-state studies of geothermal systems and groundwater flow. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved sing the finite element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat and mass transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model and the numerical solution procedure are provided in this report. A user`s guide and sample problems are also included. The FEHMN (Finite Element Heat and Mass Nuclear) code, described in this report, is a version of FEHM (Finite Element Heat and Mass, Zyvoloski et al., 1988) developed for the Yucca Mountain Site Characterization Project (YMP). The main use of FEHMN will be to assist in the understanding of flow fields in the saturated zone below the potential Yucca Mountain repository.

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1992-05-01T23:59:59.000Z

144

Extended finite element method on polygonal and quadtree meshes  

E-Print Network (OSTI)

Adaptive re?nement for B-spline ?nite element, Internationalmatrix. The application of B-spline ?nite elements [27],

Tabarraei, A.; Sukumar, N.

2008-01-01T23:59:59.000Z

145

Multiscale finite element methods for high-contrast problems using local spectral basis functions  

Science Conference Proceedings (OSTI)

In this paper we study multiscale finite element methods (MsFEMs) using spectral multiscale basis functions that are designed for high-contrast problems. Multiscale basis functions are constructed using eigenvectors of a carefully selected local spectral ... Keywords: High contrast, Multiscale finite element, Porous media, Spectral

Yalchin Efendiev; Juan Galvis; Xiao-Hui Wu

2011-02-01T23:59:59.000Z

146

Optimization of a large steel truss structure used in civil engineering, by finite element method  

Science Conference Proceedings (OSTI)

This paper presents the optimized version of a steel structure used in civil engineering obtained thru a process of structural optimization using Finite Element Method. The main advantage of this optimized structure is the cost which is 50% smaller then ... Keywords: Ansys, civil engineering, finite elements method, steel structure, structural optimization

Mihai Negru; Ivona Georgescu; Emil Albota

2008-09-01T23:59:59.000Z

147

Brief paper: Distributed parameter system optimum control design via finite element discretization  

Science Conference Proceedings (OSTI)

The problem of designing an optimum distributed parameter system is considered. Fundamental concepts pertaining to the solution of optimum controls for distributed parameter systems by finite element methods are devised. It is demonstrated that methods ... Keywords: Distributed parameter systems, finite element method, numerical methods, optimal control, partial differential equations

R. K. Cavin, III; S. C. Tandon

1977-11-01T23:59:59.000Z

148

Whole-Body Cerenkov Luminescence Tomography with the Finite Element SP3 Method  

E-Print Network (OSTI)

Whole-Body Cerenkov Luminescence Tomography with the Finite Element SP3 Method JIANGHONG ZHONG, JIE Bai oversaw the review of this article. Abstract--Generation of an accurate Cerenkov luminescence-active approach toward whole-body Cerenkov luminescence tomography. The finite element framework employs

Tian, Jie

149

IMPLICIT-EXPLICIT MULTISTEP FINITE ELEMENT METHODS FOR NONLINEAR PARABOLIC PROBLEMS  

E-Print Network (OSTI)

IMPLICIT-EXPLICIT MULTISTEP FINITE ELEMENT METHODS FOR NONLINEAR PARABOLIC PROBLEMS Georgios boundary value problems for nonlinear parabolic equations. In space we discretize by finite element methods for the time discretization of a class of nonlinear parabolic problems of the form: Given T > 0 and u0 H, find

Akrivis, Georgios

150

The finite element analysis of water vapor diffusion in a brick with vertical holes  

Science Conference Proceedings (OSTI)

This paper presents a finite element analysis of water vapor diffusion in a brick with vertical holes. The isotherms, isodensity, isopressure and isohumidity surfaces considering the longitudinal and transverse direction diffusion of water vapor in a ... Keywords: brick wall, diffusion, finite element method (FEM), numerical simulation

Madalina Calbureanu; Mihai Talu; Carlos Manuel Travieso-Gonzlez; Stefan Talu; Mihai Lungu; Raluca Malciu

2010-11-01T23:59:59.000Z

151

Measurement and finite element analysis of temperature distribution in arc welding process  

Science Conference Proceedings (OSTI)

This presentation describes both the experimental measurement and finite element analysis used to study the temperature distribution during a metal inert gas (MIG) welding process, including the cooling down period. Welding was carried out on ... Keywords: FEA, MIG welding, arc welding, cracking, finite element analysis, metal inert gas welding, residual stress, simulation, temperature distribution, weldment temperature

C. K. Lee; J. Candy; C. P. H. Tan

2004-12-01T23:59:59.000Z

152

A variational multiscale finite element method for multiphase flow in porous media  

Science Conference Proceedings (OSTI)

We present a stabilized finite element method for the numerical solution of multiphase flow in porous media, based on a multiscale decomposition of pressures and fluid saturations into resolved (or grid) scales and unresolved (or subgrid) scales. The ... Keywords: Conservation laws, Finite elements, Multiphase flow, Porous media, Shocks, Stabilized methods, Variational multiscale, Waterflood

Ruben Juanes

2005-04-01T23:59:59.000Z

153

A variational multiscale finite element method for multiphase flow in porous media  

Science Conference Proceedings (OSTI)

We present a stabilized finite element method for the numerical solution of multiphase flow in porous media, based on a multiscale decomposition of pressures and fluid saturations into resolved (or grid) scales and unresolved (or subgrid) scales. The ... Keywords: conservation laws, finite elements, multiphase flow, porous media, shocks, stabilized methods, variational multiscale, waterflood

Ruben Juanes

2005-04-01T23:59:59.000Z

154

Variable order spherical harmonic expansion scheme for the radiative transport equation using finite elements  

SciTech Connect

Highlights: {yields} We developed a variable order global basis scheme to solve light transport in 3D. {yields} Based on finite elements, the method can be applied to a wide class of geometries. {yields} It is computationally cheap when compared to the fixed order scheme. {yields} Comparisons with local basis method and other models demonstrate its accuracy. {yields} Addresses problems encountered n modeling of light transport in human brain. - Abstract: We propose the P{sub N} approximation based on a finite element framework for solving the radiative transport equation with optical tomography as the primary application area. The key idea is to employ a variable order spherical harmonic expansion for angular discretization based on the proximity to the source and the local scattering coefficient. The proposed scheme is shown to be computationally efficient compared to employing homogeneously high orders of expansion everywhere in the domain. In addition the numerical method is shown to accurately describe the void regions encountered in the forward modeling of real-life specimens such as infant brains. The accuracy of the method is demonstrated over three model problems where the P{sub N} approximation is compared against Monte Carlo simulations and other state-of-the-art methods.

Surya Mohan, P., E-mail: sprerapa@cs.ucl.ac.uk [Department of Computer Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Tarvainen, Tanja, E-mail: tanja.tarvainen@uef.fi [Department of Computer Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio (Finland); Schweiger, Martin, E-mail: martins@medphys.ucl.ac.uk [Department of Computer Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Pulkkinen, Aki, E-mail: pulkkine@sten.sunnybrook.utoronto.ca [Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio (Finland); Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Toronto, M4N 3M5 (Canada); Arridge, Simon R., E-mail: S.Arridge@cs.ucl.ac.uk [Department of Computer Science, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2011-08-10T23:59:59.000Z

155

Climate Modeling with Spectral Elements  

Science Conference Proceedings (OSTI)

As an effort toward improving climate modelcomponent performance and accuracy, an atmospheric-component climate model has been developed, entitled the Spectral Element Atmospheric Climate Model and denoted as CAM_SEM. CAM_SEM includes a unique ...

Ferdinand Baer; Houjun Wang; Joseph J. Tribbia; Aim Fournier

2006-12-01T23:59:59.000Z

156

Effect of geometric shape on two-dimensional finite elements  

SciTech Connect

Three quadrilateral elements are defined. These are an eight-nodal-point serendipity element (QUAD8s), a nine-nodal-point serendipity element (QUAD9s), and a nine-nodal-point quadrilateral element composed of two six-nodal-point triangular elements (QUAD9t). The effect that the geometric shape of the element has on the approximation function of each element is discussed. Two beam problems demonstrate that when the shape of the elements becomes skewed, the QUAD9t element significantly improves the calculated results. Finally, a recommendation is made for the QUAD8s and QUAD9t to be used together for the most efficient and accurate results.

Cook, W.A.

1981-01-01T23:59:59.000Z

157

The application of the wavelet finite element method on the temperature calculation of ceramic coating diesel engine piston  

Science Conference Proceedings (OSTI)

In order to analyse the temperature distribution of diesel engine piston, the wavelet finite element was constructed based on Daubechies wavelet scale function and traditional finite element. And the temperature distribution of the conventional and ceramic ...

Bin Zhao

2011-09-01T23:59:59.000Z

158

Hexahedral finite element mesh coarsening using pillowing technique  

SciTech Connect

A techniques for coarsening a hexahedral mesh is described. The technique includes identifying a coarsening region within a hexahedral mesh to be coarsened. A boundary sheet of hexahedral elements is inserted into the hexahedral mesh around the coarsening region. A column of hexahedral elements is identified within the boundary sheet. The column of hexahedral elements is collapsed to create an extraction sheet of hexahedral elements contained within the coarsening region. Then, the extraction sheet of hexahedral elements is extracted to coarsen the hexahedral mesh.

Staten, Matthew L. (Pittsburgh, PA); Woodbury, Adam C. (Provo, UT); Benzley, Steven E. (Provo, UT); Shepherd, Jason F. (Edgewood, NM)

2012-06-05T23:59:59.000Z

159

Stress based finite element methods for solving contact problems: Comparisons between various solution methods  

Science Conference Proceedings (OSTI)

This paper deals with numerical methods for solving unilateral contact problems with friction. Although these problems are usually defined in terms of the displacement, a stress based approach to the problem is developed here. The ''equilibrium'' finite ... Keywords: Augmented Lagrangian, Condensation, Contact, Equilibrium finite elements, Friction

Franois Kuss; Frdric Lebon

2009-08-01T23:59:59.000Z

160

Two-dimensional finite element multigroup diffusion theory for neutral atom transport in plasmas  

Science Conference Proceedings (OSTI)

Solution of the energy dependent diffusion equation in two dimensions is formulated by multigroup approximation of the energy variable and general triangular mesh, finite element discretization of the spatial domain. Finite element formulation is done by Galerkin's method. Based on this formulation, a two-dimensional multigroup finite element diffusion theory code, FENAT, has been developed for the transport of neutral atoms in fusion plasmas. FENAT solves the multigroup diffusion equation in X-Y cartesian and R-Z cylindrical/toroidal geometries. Use of the finite element method allows solution of problems in which the plasma cross-section has an arbitrary shape. The accuracy of FENAT has been verified by comparing results to those obtained using the two-dimensional discrete ordinate transport theory code, DOT-4.3. Results of application of FENAT to the transport of limiter-originated neutral atoms in a tokamak fusion machine are presented.

Hasan, M.Z.; Conn, R.W.

1986-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The Study on Finite Element Analysis for Anchor Support System Optimization  

Science Conference Proceedings (OSTI)

The anchor support design is important for the design of underground engineering. The process of optimizing the anchor support design is analyzed, the finite element method is applied to it. The anchor support system is developed including fore--process, ...

Wang Lixin; Duan Lixia

2010-04-01T23:59:59.000Z

162

Finite Element Simulation of Residual Stresses in Thermo-coupled Wire Drawing Process  

Science Conference Proceedings (OSTI)

The objective of this paper is to calculate residual stress in drawn wire taking into account induced temperature due to plastic dissipation energy. Finite element analysis (FEA) for the simulation of wire drawing is applied. The general purpose FEA ...

R. Iankov; A. Van Bael; P. Van Houtte

2000-06-01T23:59:59.000Z

163

On using moving windows in finite element time domain simulation for long accelerator structures  

Science Conference Proceedings (OSTI)

A finite element moving window technique is developed to simulate the propagation of electromagnetic waves induced by the transit of a charged particle beam inside large and long structures. The window moving along with the beam in the computational domain adopts high-order finite element basis functions through p refinement and/or a high-resolution mesh through h refinement so that a sufficient accuracy is attained with substantially reduced computational costs. Algorithms to transfer discretized fields from one mesh to another, which are the keys to implementing a moving window in a finite element unstructured mesh, are presented. Numerical experiments are carried out using the moving window technique to compute short-range wakefields in long accelerator structures. The results are compared with those obtained from the normal finite element time domain (FETD) method and the advantages of using the moving window technique are discussed.

Lee, L.-Q., E-mail: liequan@gmail.co [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Candel, Arno; Ng, Cho; Ko, Kwok [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

2010-12-10T23:59:59.000Z

164

Algebraic multigrid for stabilized finite element discretizations of the Navier Stokes equation  

E-Print Network (OSTI)

A multilevel method for the solution of systems of equations generated by stabilized Finite Element discretizations of the Euler and Navier Stokes equations on generalized unstructured grids is described. The method is ...

Okusanya, Tolulope Olawale, 1972 -

2002-01-01T23:59:59.000Z

165

Structural Mechanics & Solid Mechanics A finite element toolbox to MATLAB  

E-Print Network (OSTI)

Structural Mechanics & Solid Mechanics Department of Mechanics and Materials CALFEM A finite.3 Copyright © 1999 by Structural Mechanics, LTH, Sweden. Printed by JABE Offset, Lund, Sweden. ISRN LUTVDG/TVSM--99/9001--SE (1-265) ISSN 0281-6679 Department of Mechanics and Materials Structural Mechanics #12;The

Ehrhardt, Matthias

166

Stochastic Finite Element Analysis for Multiphase Flow in Heterogeneous Porous Media  

E-Print Network (OSTI)

. This study is concerned with developing a two-dimensional multiphase model that simulates the movement of NAPL in heterogeneous aquifers. Heterogeneity is dealt with in a probabilistic sense by modeling the intrinsic permeability of the porous medium as a stochastic process. The deterministic finite element method is used to spatially discretize the multiphase flow equations. The intrinsic permeability is represented in the model via its Karhunen-Loeve expansion (Ghanem and Spanos, 1991). This is a computationally expedient representation of stochastic processes by means of a discrete set of random variables. Further, the nodal unknowns, water phase saturations and water phase pressures, are represented by their stochastic spectral expansions. This representation involves an orthogonal basis in the space of random variables. The basis consists of orthogonal polynomial chaoses of consecutive orders. The relative permeabilities of water and oil phases, and the capillary pressure are ex...

R. Ghanem; S. Dham

1998-01-01T23:59:59.000Z

167

A Finite Element-Multibody Dynamics Co-simulation Methodology Applied to FAST  

E-Print Network (OSTI)

A co-simulation methodology is explored whereby a finite element code and a multi-body dynamics code featuring flexible cantilevered beams can be coupled and interactively executed. The floating frame of reference formulation is used to develop the equations of motion. The floating frame is fixed at the blade root. Such a formulation results in ordinary differential equations without added algebraic constraints. A variety of loose coupling and tight coupling schemes are examined for this problem. To synchronize the coupling variables, a Gauss-Seidel type iterative algorithm is used. The resulting fixed-point iterations are accelerated using Aitkens adaptive relaxation technique. The methodology is evaluated for FAST, a wind turbine aeroelastic simulation code developed by NREL. As with FAST, many multi-body codes which can model flexibility employ modal methods. A proposed addition for FAST to simulate flexible effects using a finite element method module offers a potential to include a variety of non-linearities and also provides possibilities for using a high-fidelity aerodynamics module. The coupling schemes are compared and their applicability and limitations for different scenarios are pointed out. Results validating the approach are provided.

Suryakumar, Vishvas Samuel

2013-05-01T23:59:59.000Z

168

Finite element variational formulation for beams with discontinuities  

Science Conference Proceedings (OSTI)

This paper presents a variational formulation of the mechanical behaviour of beams with strong discontinuities, enhanced to simulate the strain localization process. The considered strain localization zones represent the formation of dislocations and ... Keywords: Bending elements, Dislocations, Embedded discontinuities, Hinge development, Strain localization

G. Juarez; A. G. Ayala

2012-07-01T23:59:59.000Z

169

Pamgen, a library for parallel generation of simple finite element meshes.  

SciTech Connect

Generating finite-element meshes is a serious bottleneck for large parallel simulations. When mesh generation is limited to serial machines and element counts approach a billion, this bottleneck becomes a roadblock. Pamgen is a parallel mesh generation library that allows on-the-fly scalable generation of hexahedral and quadrilateral finite element meshes for several simple geometries. It has been used to generate more that 1.1 billion elements on 17,576 processors. Pamgen generates an unstructured finite element mesh on each processor at the start of a simulation. The mesh is specified by commands passed to the library as a 'C'-programming language string. The resulting mesh geometry, topology, and communication information can then be queried through an API. pamgen allows specification of boundary condition application regions using sidesets (element faces) and nodesets (collections of nodes). It supports several simple geometry types. It has multiple alternatives for mesh grading. It has several alternatives for the initial domain decomposition. Pamgen makes it easy to change details of the finite element mesh and is very useful for performance studies and scoping calculations.

Foucar, James G.; Drake, Richard Roy; Hensinger, David M.; Gardiner, Thomas Anthony

2008-04-01T23:59:59.000Z

170

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite-element method designed for fully unstructured quadrilateral ... Keywords: atmospheric modeling, dynamical core, global circulation model, parallel scalability, spectral elements

John M. Dennis; Jim Edwards; Katherine J. Evans; Oksana Guba; Peter H. Lauritzen; Arthur A. Mirin; Amik St-Cyr; Mark A. Taylor; Patrick H. Worley

2012-02-01T23:59:59.000Z

171

FINITE ELEMENT VIBRATION ANALYSIS OF A HELICALLY WOUND TUBULAR AND LAMINATED COMPOSITE MATERIAL BEAM  

E-Print Network (OSTI)

Abstract-Finite element stiffness and consistent mass matrices are derived for helically wound, symmetrical composite tubes. The tubular element is considered to have constant cross-section and small deformations restricted to a plane. Each node has three degrees of freedom: axial and transverse displacement and rotation (slope oftransverse displacement). Shell theory and lamination theory are used to formulate element stiffness matrices. The stiffness and mass matrices derived from the helically wound tubular composite material are reduced to symmetrically laminated composite beam. The free vibration and natural frequency are investigated for five different materials: steel, aluminum, carbon/N5280, Kevlar-49/epoxy and graphite/epoxy composites and various layup configurations. One application of a rotating flexible beam is investigated. The dynamic model of the flexible rotating beam includes the coupled effect between the rigid body motion and the flexible motion. The inverse dynamic simulation is performed by a prescribed driving torque in the numerical simulation. The influence of flexibility on rigid body motion are presented and discussed. From the numerical results, the composite material strongly possesses the lower power consumption and the passive control in damping the vibration of the structure. INTRODUcnON

C. I. Chen; V. H. Mucino; E. J. Barbero

1992-01-01T23:59:59.000Z

172

Experience with automatic, dynamic load balancing and adaptive finite element computation  

SciTech Connect

Distributed memory, Massively Parallel (MP), MIMD technology has enabled the development of applications requiring computational resources previously unobtainable. Structural mechanics and fluid dynamics applications, for example, are often solved by finite element methods (FEMs) requiring, millions of degrees of freedom to accurately simulate physical phenomenon. Adaptive methods, which automatically refine or coarsen meshes and vary the order of accuracy of the numerical solution, offer greater robustness and computational efficiency than traditional FEMs by reducing the amount of computation required away from physical structures such as shock waves and boundary layers. On MP computers, FEMs frequently result in distributed processor load imbalances. To overcome load imbalance, many MP FEMs use static load balancing as a preprocessor to the finite element calculation. Adaptive methods complicate the load imbalance problem since the work per element is not uniform across the solution domain and changes as the computation proceeds. Therefore, dynamic load balancing is required to maintain global load balance. We describe a dynamic, fine-grained, element-based data migration system that maintains global load balance and is effective in the presence of changing work loads. Global load balance is achieved by overlapping neighborhoods of processors, where each neighborhood performs local load balancing. The method utilizes an automatic element management system library to which a programmer integrates the application`s computational description. The library`s flexibility supports a large class of finite element and finite difference based applications.

Wheat, S.R. [Sandia National Labs., Albuquerque, NM (United States); Devine, K.D. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Computer Science; Maccabe, A.B. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Computer Science

1993-10-01T23:59:59.000Z

173

A Free Software Three-Dimensional Structural Finite Element ... - TMS  

Science Conference Proceedings (OSTI)

Nov 7, 2007 ... Calculix is an Open Source solid mechanics modeling program written and maintained by employees of MTU Munich, an Aero Engine...

174

Discontinuous Galerkin finite element methods for hyperbolic nonconservative partial differential equations  

Science Conference Proceedings (OSTI)

We present space- and space-time discontinuous Galerkin finite element (DGFEM) formulations for systems containing nonconservative products, such as occur in dispersed multiphase flow equations. The main criterium we pose on the weak formulation is that ... Keywords: 02.60.Cb, 02.70.Dh, 35L60, 35L65, 35L67, 47.55.-t, 47.85.Dh, 65M60, 76M10, Arbitrary Lagrangian Eulerian (ALE) formulation, Discontinuous Galerkin finite element methods, Nonconservative products, Numerical fluxes, Two-phase flows

S. Rhebergen; O. Bokhove; J. J. W. van der Vegt

2008-01-01T23:59:59.000Z

175

The Uranium Processing Facility Finite Element Meshing Discussion  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

(4.5 hours total) with 16 GB RAM - Final Model: * Approximately 116 hours with 48 GB RAM * Required GTStrudl Version 32 October 25, 2011 14 Department of Energy - Natural...

176

Ultrascalable Implicit Finite Element Analyses in Solid Mechanics with over a Half a Billion Degrees of Freedom  

E-Print Network (OSTI)

We present a highly parallel finite element program, Olympus, equipped with an ultrascalable linear solver, Prometheus, applied to micro-FE bone modeling calculations on an IBM SP Power3. Scalability is demonstrated with scaled speedup studies of a non-linear analyses of a vertebral body with over a half of a billion degrees of freedom. We show parallel scalability with up to 4088 processors on the ACSI White machine. This work is significant in that, in the domain of unstructured implicit finite element analysis in solid mechanics with complex geometry, this is the first demonstration of a highly parallel, and e#cient, application of a mathematically optimal linear solution method---smoothed aggregation algebraic multigrid.

Mark F. Adams; Harun H. Bayraktar; Tony M. Keaveny; Panayiotis Papadopoulos

2004-01-01T23:59:59.000Z

177

An Object-Oriented Finite Element Framework for Multiphysics Phase Field Simulations  

SciTech Connect

The phase field approach is a powerful and popular method for modeling microstructure evolution. In this work, advanced numerical tools are used to create a phase field framework that facilitates rapid model development. This framework, called MARMOT, is based on Idaho National Laboratory's finite element Multiphysics Object-Oriented Simulation Environment. In MARMOT, the system of phase field partial differential equations (PDEs) are solved simultaneously with PDEs describing additional physics, such as solid mechanics and heat conduction, using the Jacobian-Free Newton Krylov Method. An object-oriented architecture is created by taking advantage of commonalities in phase fields models to facilitate development of new models with very little written code. In addition, MARMOT provides access to mesh and time step adaptivity, reducing the cost for performing simulations with large disparities in both spatial and temporal scales. In this work, phase separation simulations are used to show the numerical performance of MARMOT. Deformation-induced grain growth and void growth simulations are included to demonstrate the muliphysics capability.

Michael R Tonks; Derek R Gaston; Paul C Millett; David Andrs; Paul Talbot

2012-01-01T23:59:59.000Z

178

The Finite Element Analysis of Quartz Crystal Resonators with Nonlinear Plate Equations  

E-Print Network (OSTI)

in predicting the vibration frequency, energy trapping, and calculation of device properties. The analysis can. The full advantage of the finite element analysis can be taken if electrical parameters and performance-4], further analysis on important phenomena and electrical circuit parameters require the consideration

Wang, Ji

179

Finite element methods for unsaturated porous solids and their application to dam engineering problems  

Science Conference Proceedings (OSTI)

This work presents a finite element formulation of equations proposed in a companion paper to describe the hyperelastic response of three-phase porous media. Attention is paid to the development of consistent tangents required by the Newton-Raphson procedure ... Keywords: Concrete dams, Hydro-mechanical coupling, Multiphase porous media, Rock mass permeability, Unilateral constraints

C. Callari; A. Abati

2009-04-01T23:59:59.000Z

180

On the Equivalence of Semi-Lagrangian Schemes and Particle-in-Cell Finite Element Methods  

Science Conference Proceedings (OSTI)

It is shown that the semi-Lagrangian schemes with cubic spline interpolation are equivalent to a particle-in-cell finite element method. The method conserves mass, is unconditionally stable, and has a truncation error as high as fourth-order for ...

Rodolfo Bermejo

1990-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Design Optimization of Anchor Support System in Large Scale Underground Engineering Based on Finite Element Analysis  

Science Conference Proceedings (OSTI)

The anchor support design is a major content for the design of underground engineering. Proper intensity of anchor support measures helps to guarantee the surrounding rock stability and meanwhile reduce costs. A computational algorithm is proposed to ... Keywords: design optimization, anchor support, finite element analysis, underground cavern

Yuting Zhang; Ming Xiao

2009-10-01T23:59:59.000Z

182

Finite element lattice Boltzmann simulations of free surface flow in a concentric cylinder  

Science Conference Proceedings (OSTI)

The annular centrifugal contactor is a compact mixer/centrifuge device designed for liquid-liquid extraction operations in processes for recycling nuclear fuel. The flow in the annulus of a centrifugal contactor is similar to the Taylor vortex flow with ... Keywords: Concentric cylinder, Finite element method, Free surface flow, Lattice Boltzmann method

Kent E. Wardle; Taehun Lee

2013-01-01T23:59:59.000Z

183

Geological formation - drill string dynamic interaction finite-element program (GEODYN). Phase 1. Theoretical description  

DOE Green Energy (OSTI)

The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.

Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.

1984-06-01T23:59:59.000Z

184

Phase 1 user instruction manual. A geological formation - drill string dynamic interaction finite element program (GEODYN)  

DOE Green Energy (OSTI)

User instructions for the GEODYN Interactive Finite Element Computer Program are presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit - Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates non-linear, time dependent, loading and boundary conditions.

Tinianow, M.A.; Rotelli, R.L. Jr.; Baird, J.A.

1984-06-01T23:59:59.000Z

185

Unstructured mesh partition improvement for implicit finite element at extreme scale  

Science Conference Proceedings (OSTI)

Parallel simulations at extreme scale require that the mesh is distributed across a large number of processors with equal work load and minimum inter-part communications. A number of algorithms have been developed to meet these goals and graph/hypergraph-based ... Keywords: Extreme scale, Finite element, Partition improvement, Unstructured mesh

Min Zhou; Onkar Sahni; Ting Xie; Mark S. Shephard; Kenneth E. Jansen

2012-03-01T23:59:59.000Z

186

Weighted least-squares finite elements based on particle imaging velocimetry data  

Science Conference Proceedings (OSTI)

The solution of the Navier-Stokes equations requires that data about the solution is available along the boundary. In some situations, such as particle imaging velocimetry, there is additional data available along a single plane within the domain, and ... Keywords: Data assimilation, Finite element, Least-squares, Particle imaging velocimetry

J. J. Heys; T. A. Manteuffel; S. F. McCormick; M. Milano; J. Westerdale; M. Belohlavek

2010-01-01T23:59:59.000Z

187

Finite Element Analysis of a Composite Semi-Span Test Article With and Without Discrete Damage  

Science Conference Proceedings (OSTI)

AS&M, Inc. performed finite element analysis, with and without discrete damage, of a composite semi-span test article that represents the Boeing 220-passenger transport aircraft composite semi-span test article. A NASTRAN bulk data file and drawings ...

Lovejoy Andrew E.

2000-08-01T23:59:59.000Z

188

Probabilistic risk assessment for the construction phases of a bridge construction based on finite element analysis  

Science Conference Proceedings (OSTI)

To develop a design, engineering, and construction management information sharing system that allow the project participants to effectively share the information throughout the construction life cycle with the support of 3D, design and building information, ... Keywords: Construction phases, Finite element analysis, Improved response surface method, Risk assessment, Virtual construction

Taejun Cho; Tae Soo Kim

2008-04-01T23:59:59.000Z

189

Inversion of Robin coefficient by a spectral stochastic finite element approach  

Science Conference Proceedings (OSTI)

This paper investigates a variational approach to the nonlinear stochastic inverse problem of probabilistically calibrating the Robin coefficient from boundary measurements for the steady-state heat conduction. The problem is formulated into an optimization ... Keywords: Conjugate gradient method, Robin inverse problem, Spectral stochastic finite element method, Stochastic inverse problems, Uncertainty quantification

Bangti Jin; Jun Zou

2008-03-01T23:59:59.000Z

190

Expressive and scalable finite element simulation beyond 1000 cores  

E-Print Network (OSTI)

). The primary motivations are to reduce the memory overhead associated with multiple MPI processes, and to map better onto linear solvers that are known to work best when threaded (e.g. LU solvers). 1.2 Parallel file input and output DOLFIN I/O was based around... XML formats, with memory scalability achieved using SAX parsing (line-by-line read) for input, and using VTK XML output for post-processing, which uses a one-file-per-process (and per time step) model. Issues with these approaches include: XML...

Richardson, Chris J.; Wells, Garth N.

2013-01-01T23:59:59.000Z

191

Modeling Metal Powder Compaction Using Combined Finite and ...  

Science Conference Proceedings (OSTI)

Presentation Title, Modeling Metal Powder Compaction Using Combined Finite ... Optimization of Thermal Cycle for Rails with Respect to the Wear Resistance.

192

Essential Boundary Conditions with Straight C1 Finite Elements in Curved Domains  

SciTech Connect

The implementation of essential boundary conditions in C1 finite element analysis requires proper treatment of both the boundary conditions on second-order differentials of the solution and the curvature of the domain boundary. A method for the imposition of essential boundary conditions using straight elements (where the elements are not deformed to approximate a curved domain) is described. It is shown that pre-multiplication of the matrix equation by the local rotation matrix at each boundary node is not the optimal transformation. The uniquely optimal transformation is found, which does not take the form of a similarity transformation due to the non-orthogonality of the transformation to curved coordinates.

N.M. Ferraro, S.C. Jardin, X. Luo

2010-02-19T23:59:59.000Z

193

A finite element analysis technique for predicting as-sprayed residual stresses generated by the plasma spray coating process  

Science Conference Proceedings (OSTI)

It is essential to analyze the residual stresses during the deposition of plasma sprayed coatings since they adversely affect the coatings' performance during their service. In this article, finite element coupled heat transfer and elastic-plastic thermal ... Keywords: Finite element analysis, Heat transfer, Plasma spraying, Residual stresses, Thermal barrier coatings

H. W. Ng; Z. Gan

2005-07-01T23:59:59.000Z

194

A geometrically-conservative, synchronized, flux-corrected remap for arbitrary Lagrangian-Eulerian computations with nodal finite elements  

Science Conference Proceedings (OSTI)

This article describes a conservative synchronized remap algorithm applicable to arbitrary Lagrangian-Eulerian computations with nodal finite elements. In the proposed approach, ideas derived from flux-corrected transport (FCT) methods are extended to ... Keywords: Arbitrary Lagrangian-Eulerian methods, Compatible discretizations, Geometric conservation law, Meteorological flows, Nodal finite element method, Remap, Shock hydrodynamics

A. LPez Ortega; G. Scovazzi

2011-07-01T23:59:59.000Z

195

From Single-Phase To Compositional Flow: Applicability Of Mixed Finite Elements  

E-Print Network (OSTI)

. In this paper we discuss the formulation of the governing equations that describe flow of fluids in porous media. Various types of fluid flow, ranging from single-phase flow to compositional flow, are considered. It is shown that all the differential equations governing these types of flow can be effectively rewritten in a fractional flow formulation; i.e., in terms of a global pressure and saturation (or saturations), and that mixed finite element methods can be accurately exploited to solve the pressure equation. Extensive numerical results are presented to see the performance of the mixed methods for the flow equations using different mixed finite elements. 1. Introduction Multiphase flow of fluids in porous media is physically and chemically complex. It involves heterogeneities in the porous media at many different length scales and complicated processes such as diffusion and dispersion. Numerical simulation of these phenomena is a critical step in understanding multicom...

Zhangxin Chen; Richard E. Ewing

1997-01-01T23:59:59.000Z

196

Finite element strategies for the efficient analysis and evaluation of solar collector structures  

DOE Green Energy (OSTI)

Concentrating or reflecting structures for solar energy systems must be evaluated as to their structural integrity and optical performance. Computer studies can be used as an integral part of these evaluations. The computer studies make use of finite element structural codes coupled with post-processors that calculate optical data. If the analysis of a solar structure is to be carried out in an efficient manner, these computer codes must have certain capabilities. A number of solar energy projects at Sandia National Laboratories have made extensive use of finite element analyses. The analyses have been useful in evaluating design concepts which hold promise for large scale use in solar energy projects. Analysis procedures have been developed for some structures so that evaluations can be carried out in a straightforward manner.

Koteras, J. R.

1980-01-01T23:59:59.000Z

197

B-Spline Finite Elements and their Efficiency in Solving Relativistic Mean Field Equations  

E-Print Network (OSTI)

A finite element method using B-splines is presented and compared with a conventional finite element method of Lagrangian type. The efficiency of both methods has been investigated at the example of a coupled non-linear system of Dirac eigenvalue equations and inhomogeneous Klein-Gordon equations which describe a nuclear system in the framework of relativistic mean field theory. Although, FEM has been applied with great success in nuclear RMF recently, a well known problem is the appearance of spurious solutions in the spectra of the Dirac equation. The question, whether B-splines lead to a reduction of spurious solutions is analyzed. Numerical expenses, precision and behavior of convergence are compared for both methods in view of their use in large scale computation on FEM grids with more dimensions. A B-spline version of the object oriented C++ code for spherical nuclei has been used for this investigation.

W. Poeschl

1998-08-26T23:59:59.000Z

198

B-Spline Finite Elements and their Efficiency in Solving Relativistic Mean Field Equations  

E-Print Network (OSTI)

A finite element method using B-splines is presented and compared with a conventional finite element method of Lagrangian type. The efficiency of both methods has been investigated at the example of a coupled non-linear system of Dirac eigenvalue equations and inhomogeneous Klein-Gordon equations which describe a nuclear system in the framework of relativistic mean field theory. Although, FEM has been applied with great success in nuclear RMF recently, a well known problem is the appearance of spurious solutions in the spectra of the Dirac equation. The question, whether B-splines lead to a reduction of spurious solutions is analyzed. Numerical expenses, precision and behavior of convergence are compared for both methods in view of their use in large scale computation on FEM grids with more dimensions. A B-spline version of the object oriented C++ code for spherical nuclei has been used for this investigation.

Pschl, W

1997-01-01T23:59:59.000Z

199

FEHMN 1.0: Finite element heat and mass transfer code  

DOE Green Energy (OSTI)

A computer code is described which can simulate non-isothermal multiphase multicomponent flow in porous media. It is applicable to natural-state studies of geothermal systems and ground-water flow. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved using the finite element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat and mass transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model and the numerical solution procedure are provided in this report. A user`s guide and sample problems are also included. The main use of FEHMN will be to assist in the understanding of flow fields in the saturated zone below the proposed Yucca Mountain Repository. 33 refs., 27 figs., 12 tabs.

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1991-04-01T23:59:59.000Z

200

Superconvergence of finite element approximations by a computer-based approach  

E-Print Network (OSTI)

In this thesis we present a study of superconvergence which can be applied to practical meshes. We introduce a new definition of superconvergence which extends the classical definition to practical computations. The new definition allows us to determine points of least error for entire classes of local geometries, materials and element types. Based on the new definition we developed a methodology to study superconvergence in practical grids. This methodology is completely computer-based. We give several examples to show the application of this methodology to finite element meshes like the ones employed in engineering computations.

Gangaraj, Srihari Kumar

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Finite Element Analysis of Ballistic Penetration of Plain Weave Twaron CT709 Fabrics: A Parametric Study  

E-Print Network (OSTI)

The ballistic impact of Twaron CT709 plain weave fabrics is studied using an explicit finite element method. Many existing approximations pertaining to woven fabrics cannot adequately represent strain rate-dependent behavior exhibited by the Twaron fabrics. One-dimensional models based on linear viscoelasticity can account for rate dependency but are limited by the simplifying assumptions on the fabric architecture and stress state. In the current study, a three-dimensional fabric model is developed by treating each individual yarn as a continuum. The yarn behavior is phenomenologically described using a three-dimensional linear viscoelastic constitutive relation. A user subroutine VUMAT for ABAQUS/Explicit is developed to incorporate the constitutive behavior. By using the newly developed viscoelasticity model, a parametric study is carried out to analyze the effects of various parameters on the impact behavior of the Twaron fabrics, which include projectile shape and mass, gripping conditions, inter-yarn friction, and the number of fabric layers. The study leads to the determination of the optimal number of fabric layers and the optimized level of inter-yarn friction that are needed to achieve the maximum energy absorption at specified impact speeds. The present study successfully utilizes the combination of 3D weave architecture and the strain rate dependent material behavior. Majority of the existing work is based either on geometry simplification or assumption of elastic material behavior. Another significant advantage with the present approach is that the mechanical constitutive relation, coded in FORTRAN, is universal in application. The desired material behavior can be obtained by just varying the material constants in the code. This allows for the extension of this work to any fabric material which exhibits a strain-rate dependent behavior in addition to Twaron. The results pertaining to optimal number of fabric layers and inter-yarn friction levels can aid in the manufacturing of fabric with regard to the desired level of lubrication/additives to improve the fabric performance under impact.

Gogineni, Sireesha

2010-08-01T23:59:59.000Z

202

The Free Kelvin Wave in Finite-Difference Numerical Models  

Science Conference Proceedings (OSTI)

The effects of viscosity and finite- differencing on free Kelvin waves in numerical models (which employ the Arakawa B- or C-grid difference schemes) are investigated using the f-plane shallow-water equations with offshore finite-difference grids,...

William W. Hsieh; Michael K. Davey; Roxana C. Wajsowicz

1983-08-01T23:59:59.000Z

203

Visualization methods for high-resolution, transient, 3-D, finite element situations  

SciTech Connect

Scientific visualization is the process whereby numerical data is transformed into a visual form to augment the process of discovery and understanding. Visualizing the data generated by large-scale, transient, three-dimensional finite element simulations poses many challenges due to geometric complexity, the presence of multiple materials and multiple element types, and the inherent unstructured nature of the meshes. In this paper, the direct use of finite element data structures, nodal assembly procedures, and element interpolants for volumetric adaptive surface extraction, surface rendering, vector grids and particle tracing is discussed. A brief description of a {open_quotes}direct-to-disk{close_quotes} animation system is presented, and case studies which demonstrate the use of isosurfaces, vector plots, cutting planes, reference surfaces and particle tracing are then discussed in the context of several case studies for transient incompressible viscous flow, and acoustic fluid-structure interaction simulations. An overview of the implications of massively parallel computers on visualization is presented to highlight the issues in parallel visualization methodology, algorithms. data locality and the ultimate requirements for temporary and archival data storage and network bandwidth.

Christon, M.A.

1995-01-10T23:59:59.000Z

204

Finite element analysis of bending in a threaded connector for a 5 1/2-in. Marine riser  

Science Conference Proceedings (OSTI)

This paper describes the development of a new finite element modelling technique for performing nonlinear bending analysis of tubulars and its application to a threaded connector for a 5-1/2 inch production tubing marine riser. A finite element technique has been developed for analyzing bending loads applied to an axisymmetric geometry. The method uses a Fourier series solution. The first two terms of the series are solved simultaneously, allowing nonlinearities to be included since the method does not use superposition, which normally requires linearity. Existing methods of analysis require either a linear elastic assumption, and axisymmetric approximation of bending loads, or a full three dimensional analysis. The new technique includes nonlinearities in mechanical properties, gapping, and friction. It is more accurate than the method where axisymmetric loads are applied so that pipe OD stresses are the same as those that would result from bending. The model is considerably less complicated to use than a three dimensional model and is also considerably less expensive. The method described above is applied to a 5-1/2 inch threaded connector. The connector is analyzed under make-up, tension, pressure, bending, and shear loads. Predictions include average and reversing stresses in the pin and box wall and at stress concentrations. These predictions can be used to evaluate the fatigue life of the connector.

Allen, M.B.; Eichberger, L.C.

1984-05-01T23:59:59.000Z

205

Free Planetary Waves in Finite-Difference Numerical Models  

Science Conference Proceedings (OSTI)

The effects of spatial finite-differencing, viscosity and diffusion on unbounded planetary waves in numerical models are investigated using a quasi-geostrophic approximation to the midlatitude, ?-plane, shallow-water equations. The two-...

Roxana C. Wajsowicz

1986-04-01T23:59:59.000Z

206

Energy- and enstrophy-conserving schemes for the shallow-water equations, based on mimetic finite elements  

E-Print Network (OSTI)

This paper presents a family of spatial discretisations of the nonlinear rotating shallow-water equations that conserve both energy and potential enstrophy. These are based on two-dimensional mixed finite element methods, and hence, unlike some finite difference methods, do not require an orthogonal grid. Numerical verification of the aforementioned properties is also provided.

McRae, Andrew T T

2013-01-01T23:59:59.000Z

207

A Moving-Mesh Finite Element Method and its Application to the Numerical Solution of Phase-Change  

E-Print Network (OSTI)

School of Computing, University of Leeds, UK R. Mahmood Computer Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad, Pakistan A distributed Lagrangian moving-mesh finite element

Jimack, Peter

208

A Preliminary Finite Element Electrochemical Model for Modelling ...  

Science Conference Proceedings (OSTI)

Retrofit of a Combined Breaker Feeder with a Chisel Bath Contact Detection System to Reduce Anode Effect Frequency in a Potroom Simulating Traffic in a...

209

An approach for modelling concrete spalling in finite strains  

Science Conference Proceedings (OSTI)

A new approach for modelling concrete spalling process is here proposed, taking into account a fully nonlinear-displacement/strain theory able to catch complex interactions between pressure, thermal and mechanical fields. The micro-structural modelling ... Keywords: Concrete spalling, Finite strains, Micro-structural modelling

C. E. Majorana; V. A. Salomoni; G. Mazzucco; G. A. Khoury

2010-04-01T23:59:59.000Z

210

Finite element formulation of the self-excited forces for time-domain assessment of wind-induced dynamic response and flutter stability limit of cable-supported bridges  

Science Conference Proceedings (OSTI)

In this paper it is shown how unsteady self-excited aerodynamic forces modelled by rational functions can be introduced into a finite element beam model, using the nodal displacement degrees of freedom of the element to characterize the aeroelastic system. ... Keywords: Aerodynamic derivatives, Cable-supported bridges, FEM, Flutter, Wind loading

Ole Iseth; Anders RNnquist; Ragnar SigbjRnsson

2012-03-01T23:59:59.000Z

211

COYOTE : a finite element computer program for nonlinear heat conduction problems. Part I, theoretical background.  

SciTech Connect

The need for the engineering analysis of systems in which the transport of thermal energy occurs primarily through a conduction process is a common situation. For all but the simplest geometries and boundary conditions, analytic solutions to heat conduction problems are unavailable, thus forcing the analyst to call upon some type of approximate numerical procedure. A wide variety of numerical packages currently exist for such applications, ranging in sophistication from the large, general purpose, commercial codes, such as COMSOL, COSMOSWorks, ABAQUS and TSS to codes written by individuals for specific problem applications. The original purpose for developing the finite element code described here, COYOTE, was to bridge the gap between the complex commercial codes and the more simplistic, individual application programs. COYOTE was designed to treat most of the standard conduction problems of interest with a user-oriented input structure and format that was easily learned and remembered. Because of its architecture, the code has also proved useful for research in numerical algorithms and development of thermal analysis capabilities. This general philosophy has been retained in the current version of the program, COYOTE, Version 5.0, though the capabilities of the code have been significantly expanded. A major change in the code is its availability on parallel computer architectures and the increase in problem complexity and size that this implies. The present document describes the theoretical and numerical background for the COYOTE program. This volume is intended as a background document for the user's manual. Potential users of COYOTE are encouraged to become familiar with the present report and the simple example analyses reported in before using the program. The theoretical and numerical background for the finite element computer program, COYOTE, is presented in detail. COYOTE is designed for the multi-dimensional analysis of nonlinear heat conduction problems. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in COYOTE are also outlined. Instructions for use of the code are documented in SAND2010-0714.

Glass, Micheal W.; Hogan, Roy E., Jr.; Gartling, David K.

2010-03-01T23:59:59.000Z

212

Comparative Finite Element Analysis of the Stress-Strain States in Three Different Bonded Solid Oxide Fuel Cell Seal Designs  

DOE Green Energy (OSTI)

One of the critical issues in designing and fabricating a high performance planar solid oxide fuel cell (pSOFC) stack is the development of the appropriate materials and techniques for hermetically sealing the metal and ceramic components. We are currently developing a foil-based approach that appears to offer good hermeticity and mechanical integrity, while minimizing the generation of interfacial stresses in either of the joint substrate materials, particulary the ceramic cell. Prior experimental work conducted on small-scale samples demonstrated the viability of the concept. Here we present recent results from computational analyses undertaken to investigate potential issues associated with scaling up the seal to full-scale pSOFC stack dimensions/geometry. Here we employ finite element modeling to assess the potential thermal cycling performance of this design, specifically as it pertains to sealing components with vastly different thermal expansion properties.

Weil, K. Scott; Koeppel, Brian J.

2008-05-15T23:59:59.000Z

213

Extended finite state models of language  

Science Conference Proceedings (OSTI)

In spite of the wide availability of more powerful (context free, mildly context sensitive, and even Turing-equivalent) formalisms, the bulk of the applied work on language and sublanguage modeling, especially for the purposes of recognition and topic ...

Andrs Kornai

1996-12-01T23:59:59.000Z

214

Nano-Optical Device Design with the Use of Open-Source Parallel Version FDTD and Commercial Finite Element Package  

E-Print Network (OSTI)

In this paper, the implementation of open-source parallel-version FDTD (Finite-Difference-Time-Domain) software, MEEP, on Texas A&M supercomputers and commercial finite element package, COMSOL, on a single workstation for the design design of nano-optical device is reported. The the computer architecture and performance of both numerical methods on the same design will be briefly described.

Liu, Y

2013-01-01T23:59:59.000Z

215

Lagrangian finite element analysis of the penetration of earth penetrating weapons  

SciTech Connect

Buried targets, such as hardened missile silos, that are resistant to the effects of air blast from above-ground or surface-burst explosions may be vulnerable to the effects of ground motion produced by nearby underground explosions. An earth penetrating weapon (EPW) is being developed to exploit this phenomena. To design the EPW system, loads on the weapon due to the penetration event must be determined. This paper presents the methodology for performing Lagrangian finite-element analysis of the penetration event in two and three dimensions. In order to describe the methodology, results from analyses done for a particular EPW impacting a particular target medium are presented. The results for impacts with nonzero angles of incidence and nonzero angles of attack show the importance of being able to calculate three dimensional penetration loads. 62 figs.

Rosinsky, R.W.

1985-11-22T23:59:59.000Z

216

Laminar backward-facing step flow using the finite element method  

SciTech Connect

Laminar, incompressible flow over a backward-facing step is calculated using a finite element spatial discretization with a piecewise continuous pressure approximation and an explicit time marching algorithm. The time-accurate evolution to steady state is demonstrated for both two-dimensional (2D) and three-dimensional (3D) simulations. This approach is shown to accurately predict the lengths of the recirculation zone on the top wall and at the step for various meshes and domain lengths, for a Reynolds number of 800 based on the average inlet velocity and twice the inlet channel height. The instantaneous and steady-state results are investigated. The steady-state solutions are evaluated by comparison to published numerical and experimental results.

Kornblum, B.; McCallen, R. [Lawrence Livermore National Lab., CA (United States); Christon, M.A. [Sandia National Labs., Albuquerque, NM (United States); Kollmann, W. [Univ. of California, Davis, CA (United States) Dept. of Mechanical and Aeronautical Engineering] [and others

1995-11-01T23:59:59.000Z

217

A posteriori error estimates in finite element methods for general Friedrichs' systems.  

E-Print Network (OSTI)

In this paper we develop and analyse a new a posteriori error estimator for general Friedrichs' systems valid for most classical finite element approximations. This error estimator is based on comparison between an appropriate norm of the exact error, and the L 2 -norm of the residuals of the approximate solution. We prove that the estimator is independent of the dimension of the space and of the numerical approximation method used. Moreover the global majoration and local minoration constants are independent of the shape of the mesh. 1 Introduction A well known difficulty of the numerical solution of Friedrichs' systems is the problem of numerically resolving discontinuities, characteristic of solutions of hyperbolic problems, while simultaneously producing high-order, non-oscillatory results. The basic issue of the quality of the numerical solution obtained is fundamentally important : how accurate is this solution ? Adaptive methods attempt to answer these questions. The goal is ...

B. Achchab; A. Agouzal; J. Baranger; J.F. Maitre

1997-01-01T23:59:59.000Z

218

Evaluation of the matrix exponential function using finite elements in time  

E-Print Network (OSTI)

The evaluation of a matrix exponential function is a classic problem of computational linear algebra. Many different methods have been employed for its numerical evaluation [Moler C and van Loan C 1978 SIAM Review 20 4], none of which produce a definitive algorithm which is broadly applicable and sufficiently accurate, as well as being reasonably fast. Herein, we employ a method which evaulates a matrix exponential as the solution to a first-order initial value problem in a fictitious time variable. The new aspect of the present implementation of this method is to use finite elements in the fictitious time variable. [Weatherford C A, Red E, and Wynn A 2002 Journal of Molecular Structure 592 47] Then using an expansion in a properly chosen time basis, we are able to make accurate calculations of the exponential of any given matrix as the solution to a set of simultaneous equations.

Gebremedhin, D H; Zhang, X; Wynn, A; Tanaka, G

2008-01-01T23:59:59.000Z

219

Evaluation of the matrix exponential function using finite elements in time  

E-Print Network (OSTI)

The evaluation of a matrix exponential function is a classic problem of computational linear algebra. Many different methods have been employed for its numerical evaluation [Moler C and van Loan C 1978 SIAM Review 20 4], none of which produce a definitive algorithm which is broadly applicable and sufficiently accurate, as well as being reasonably fast. Herein, we employ a method which evaulates a matrix exponential as the solution to a first-order initial value problem in a fictitious time variable. The new aspect of the present implementation of this method is to use finite elements in the fictitious time variable. [Weatherford C A, Red E, and Wynn A 2002 Journal of Molecular Structure 592 47] Then using an expansion in a properly chosen time basis, we are able to make accurate calculations of the exponential of any given matrix as the solution to a set of simultaneous equations.

D H Gebremedhin; C A Weatherford; X Zhang; A Wynn III; G Tanaka

2008-11-17T23:59:59.000Z

220

Finite element analysis of the Arquin-designed CMU wall under a dynamic (blast) load.  

Science Conference Proceedings (OSTI)

The Arquin Corporation designed a CMU (concrete masonry unit) wall construction and reinforcement technique that includes steel wire and polymer spacers that is intended to facilitate a faster and stronger wall construction. Since the construction method for an Arquin-designed wall is different from current wall construction practices, finite element computer analyses were performed to estimate the ability of the wall to withstand a hypothetical dynamic load, similar to that of a blast from a nearby explosion. The response of the Arquin wall was compared to the response of an idealized standard masonry wall exposed to the same dynamic load. Results from the simulations show that the Arquin wall deformed less than the idealized standard wall under such loading conditions. As part of a different effort, Sandia National Laboratories also looked at the relative static response of the Arquin wall, results that are summarized in a separate SAND Report.

Lopez, Carlos; Petti, Jason P.

2008-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Chiral Sigma Model with Pion Mean Field in Finite Nuclei  

E-Print Network (OSTI)

The properties of infinite matter and finite nuclei are studied by using the chiral sigma model in the framework of the relativistic mean field theory. We reconstruct an extended chiral sigma model in which the omega meson mass is generated dynamically by the sigma condensation in the vacuum in the same way as the nucleon mass. All the parameters of chiral sigma model are essentially fixed from the hadron properties in the free space. In nuclear matter, the saturation property comes out right, but the incompressibility is too large and the scalar and vector potentials are about a half of the phenomenological ones, respectively. This fact is reflected to the properties of finite nuclei. We calculate N = Z even-even mass nuclei between N = 16 and N = 34. The extended chiral sigma model without the pion mean field leads to the result that the magic number appears at N = 18 instead of N = 20 and the magic number does not appear at N = 28 due to the above mentioned nuclear matter properties. The latter problem, however, could be removed by the introduction of the finite pion mean field with the appearance of the magic number at N = 28. We find that the energy differences between the spin-orbit partners are reproduced by the finite pion mean field which is completely a different mechanism from the standard spin-orbit interaction.

Y. Ogawa; H. Toki; S. Tamenaga; H. Shen; A. Hosaka; S. Sugimoto; K. Ikeda

2003-12-13T23:59:59.000Z

222

Finite automata models of quantized systems: conceptual status and outlook  

E-Print Network (OSTI)

Since Edward Moore, finite automata theory has been inspired by physics, in particular by quantum complementarity. We review automaton complementarity, reversible automata and the connections to generalized urn models. Recent developments in quantum information theory may have appropriate formalizations in the automaton context.

Karl Svozil

2002-09-15T23:59:59.000Z

223

Test of modified BCS model at finite temperature  

E-Print Network (OSTI)

A recently suggested modified BCS (MBCS) model has been studied at finite temperature. We show that this approach does not allow the existence of the normal (non-superfluid) phase at any finite temperature. Other MBCS predictions such as a negative pairing gap, pairing induced by heating in closed-shell nuclei, and ``superfluid -- super-superfluid'' phase transition are discussed also. The MBCS model is tested by comparing with exact solutions for the picket fence model. Here, severe violation of the internal symmetry of the problem is detected. The MBCS equations are found to be inconsistent. The limit of the MBCS applicability has been determined to be far below the ``superfluid -- normal'' phase transition of the conventional FT-BCS, where the model performs worse than the FT-BCS.

V. Yu. Ponomarev; A. I. Vdovin

2005-08-24T23:59:59.000Z

224

Two-dimensional finite element simulation of fracture and fatigue behaviours of alumina microstructures for hip prosthesis  

E-Print Network (OSTI)

, finite element, fatigue, fracture, ceramic, microstructure * Corresponding author. Email address: geringer@emse.fr #12;2 1. Introduction Alumina is known as a primary ceramic material in biomedical industry. Particularly, Al2O3 is widely used as the material of a femoral head and an acetabular cup of hip

Paris-Sud XI, Université de

225

A CAE-integrated distributed collaborative design system for finite element analysis of complex product based on SOOA  

Science Conference Proceedings (OSTI)

Large-scale finite element analysis of complex product needs a wider support from external CAE resources. This paper proposes a method of the distributed concurrent and collaborative design in the distributed intelligent resources environment to use ... Keywords: Collaborative design, Distributed CAE resources, Service object-oriented architecture (SOOA)

Jiaqing Yu; Jianzhong Cha; Yiping Lu; Wensheng Xu; M. Sobolewski

2010-04-01T23:59:59.000Z

226

Nonlinear finite-element analysis of a reinforced-concrete Mark III containment under pressure and gravity loads. [BWR  

DOE Green Energy (OSTI)

An analysis of a Mark III reactor containment vessel subjected to a uniformly increasing internal pressure and gravity loads is carried out in order to ascertain the load carrying capacity of the structure under hydrogen burn. The analysis is conducted by using a nonlinear finite element model that includes nonlinearities in the strain-displacement relations as well as in the material constitutive equations. In this analysis, the nonlinear behavior of the liner and reinforcement steels is described by a von Mises elastic-plastic model with isotropic hardening. A recently developed elastic-plastic-fracture model that includes both the cracking and crushing limit states is used for the plain concrete. Consistent smearing and de-smearing procedures are then used to represent the composite material properties of the reinforced concrete by an anisotropic and locally homogeneous continuum. Results pertaining to the critical regions of the containment where cracking of the concrete, yielding of the reinforcement bars, and substantial straining of the liner take place are discussed.

Sharma, S.; Reich, M.; Shteyngart, S.; Chang, T.Y.

1983-01-01T23:59:59.000Z

227

Finite-volume model for chemical vapor infiltration incorporating radiant heat transfer. Interim report  

SciTech Connect

Most finite-volume thermal models account for the diffusion and convection of heat and may include volume heating. However, for certain simulation geometries, a large percentage of heat flux is due to thermal radiation. In this paper a finite-volume computational procedure for the simulation of heat transfer by conduction, convection and radiation in three dimensional complex enclosures is developed. The radiant heat transfer is included as a source term in each volume element which is derived by Monte Carlo ray tracing from all possible radiating and absorbing faces. The importance of radiative heat transfer is illustrated in the modeling of chemical vapor infiltration (CVI) of tubes. The temperature profile through the tube preform matches experimental measurements only when radiation is included. An alternative, empirical approach using an {open_quotes}effective{close_quotes} thermal conductivity for the gas space can match the initial temperature profile but does not match temperature changes that occur during preform densification.

Smith, A.W.; Starr, T.L. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

1995-05-01T23:59:59.000Z

228

Finite element analyses of continuous filament ties for masonry applications : final report for the Arquin Corporation.  

Science Conference Proceedings (OSTI)

Finite-element analyses were performed to simulate the response of a hypothetical vertical masonry wall subject to different lateral loads with and without continuous horizontal filament ties laid between rows of concrete blocks. A static loading analysis and cost comparison were also performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Simulations of vertical walls subject to static loads representing 100 mph winds (0.2 psi) and a seismic event (0.66 psi) showed that the simulated walls performed similarly and adequately when subject to these loads with and without the ties. Additional simulations and tests are required to assess the performance of actual walls with and without the ties under greater loads and more realistic conditions (e.g., cracks, non-linear response).

Quinones, Armando, Sr. (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei

2008-08-01T23:59:59.000Z

229

Insider Models with Finite Utility in Markets with Jumps  

SciTech Connect

In this article we consider, under a Levy process model for the stock price, the utility optimization problem for an insider agent whose additional information is the final price of the stock blurred with an additional independent noise which vanishes as the final time approaches. Our main interest is establishing conditions under which the utility of the insider is finite. Mathematically, the problem entails the study of a 'progressive' enlargement of filtration with respect to random measures. We study the jump structure of the process which leads to the conclusion that in most cases the utility of the insider is finite and his optimal portfolio is bounded. This can be explained financially by the high risks involved in models with jumps.

Kohatsu-Higa, Arturo, E-mail: arturokohatsu@gmail.com [Ritsumeikan University, Department of Mathematical Sciences (Japan); Yamazato, Makoto, E-mail: yamazato@math.u-ryukyu.ac.jp [University of the Ryukyus, Department of Mathematics, Faculty of Science (Japan)

2011-10-15T23:59:59.000Z

230

A Finite-Depth Wind-Wave Model. Part I: Model Description  

Science Conference Proceedings (OSTI)

A parametric windsea model for arbitrary water depths is presented. The model is derived from a conservation of energy flux formulation and includes shoaling, refraction, dissipation by bottom friction, as well as finite-depth modifications of ...

Hans C. Graber; Ole S. Madsen

1988-11-01T23:59:59.000Z

231

The Combined Finite-Discrete Element Method applied to the Study of Rock Fracturing Behavior in 3D  

Science Conference Proceedings (OSTI)

Since its introduction the combined finite-discrete element method (FEM/DEM), has become an excellent tool to address a wide range of problems involving fracturing and fragmentation of solids. Within the context of rock mechanics, the FEM/DEM method has been applied to many complex industrial problems such as block caving, deep mining techniques, rock blasting, seismic waves, packing problems, rock crushing problems, etc. In the real world most of the problems involving fracture and fragmentation of solids are three dimensional problems. With the aim of addressing these problems an improved 2D/3D FEM/DEM capability has been developed at Los Alamos National Laboratory (LANL). These capabilities include state of the art 3D contact detection, contact interaction, constitutive material models, and fracture models. In this paper, Split Hopkinson Pressure Bar (SHPB) Brazilian experiments are simulated using this improved 2D/3D FEM/DEM approach which is implemented in LANL's MUNROU (Munjiza-Rougier) code. The results presented in this work show excellent agreement with both the SHPB experiments and previous 2D numerical simulations performed by other FEM/DEM research groups.

Rougier, Esteban [Los Alamos National Laboratory; Bradley, Christopher R. [Los Alamos National Laboratory; Broom, Scott T. [Geomechanics Sandia National Laboratories; Knight, Earl E. [Los Alamos National Laboratory; Munjiza, Ante [School of Engineering and Material Sciences, Queen Mary, University of London; Sussman, Aviva J. [Los Alamos National Laboratory; Swift, Robert P. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

232

Coupled Transient Finite Element Simulation of Quench in Jefferson Lab's 11 GeV Super High Momentum Spectrometer Superconducting Magnets  

Science Conference Proceedings (OSTI)

This paper presents coupled transient thermal and electromagnetic finite element analysis of quench in the Q2, Q3, and dipole superconducting magnets using Vector Fields Quench code. Detailed temperature distribution within coils and aluminum force collars were computed at each time step. Both normal (quench with dump resistor) and worst-case (quench without dump resistor) scenarios were simulated to investigate the maximum temperatures. Two simulation methods were utilized, and their algorithms, implementation, advantages, and disadvantages are discussed. The first method simulated the coil using nonlinear transient thermal analysis directly linked with the transient circuit analysis. It was faster because only the coil was meshed and no eddy current was modeled. The second method simulated the whole magnet including the coil, the force collar, and the iron yoke. It coupled thermal analysis with transient electromagnetic field analysis which modeled electromagnetic fields including eddy currents within the force collar. Since eddy currents and temperature in the force collars were calculated in various configurations, segmentation of the force collars was optimized under the condition of fast discharge.

E. Sun, P. Brindza, S. Lassiter, M. Fowler, E. Xu

2010-06-01T23:59:59.000Z

233

Anisotropic Finite Element Modeling of the Fused Deposition ...  

Science Conference Proceedings (OSTI)

Differential Characterization of Ikperejere Iron shale and Iron Sandstone Deposit Direct Precipitation of Sr-doped LaP3O9 Thin Film Electrolytes for...

234

Comparison of Classical Tools and Modern Finite Element Modeling ...  

Science Conference Proceedings (OSTI)

... including: operating practice, slag conductivity, temperature, power intensity, ... Design and Commissioning of the Ausmelt TSL Lead Smelter at Yunnan Tin...

235

Incorporating Radiant Heat Exchange into Finite Element Models of ...  

Science Conference Proceedings (OSTI)

In order to simplify this non-linear mode of heat transfer, the effects of ... Technical Risk Mitigation Through Rheometallurgical Generation of Process and...

236

Development of a Finite Element Model of Warping Inflatable Wings  

E-Print Network (OSTI)

fabric composites that harden after deployment and exposure to UV radiation or of rugged woven materials, internal pressurization and a woven fabric shell structure. This effort includes determination of material

Jacob, Jamey

237

Finite Element Modeling of Shallow Foundations on Nonlinear Soil Medium  

E-Print Network (OSTI)

Engineering Mechanics Division, ASCE, 102(EM2): 249-263. [Engineering Division, ASCE, 105(GT12):1435- 1454. [5]Engineering Mechanics Division, ASCE, 97(EM5):1381-1395. [7

Zhang, Jian; Tang, Yuchuan

2007-01-01T23:59:59.000Z

238

Finite Element Welding Model for the Assessment of Residual ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Advances in Hydroelectric Turbine Manufacturing and Repair. Presentation...

239

Development of a Finite Element Model for Radial Forging of ...  

Science Conference Proceedings (OSTI)

end by chuckheads, which are track bound manipulators, When producing round products, the chuckheads rotate the work piece between blows to obtain a...

240

A hierarchical fracture model for the iterative multiscale finite volume method  

Science Conference Proceedings (OSTI)

An iterative multiscale finite volume (i-MSFV) method is devised for the simulation of multiphase flow in fractured porous media in the context of a hierarchical fracture modeling framework. Motivated by the small pressure change inside highly conductive ... Keywords: Fractured porous media, Hierarchical fractured modeling, Iterative multiscale finite volume, Iterative multiscale methods, Multiscale finite volume, Multiscale fracture modeling, Multiscale methods

Hadi Hajibeygi; Dimitris Karvounis; Patrick Jenny

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Three-Dimensional Modeling of Shape Memory Polymers Considering Finite Deformations and Heat Transfer  

E-Print Network (OSTI)

Shape memory polymers (SMPs) are a relatively new class of active materials that can store a temporary shape and return to the original configuration upon application of a stimulus such as temperature. This shape changing ability has led to increased interest in their use for biomedical and aerospace applications. A major challenge, however, in the advancement of these applications is the ability to accurately predict the material behavior for complex geometries and boundary conditions. This work addresses this challenge by developing an experimentally calibrated and validated constitutive model that is implemented as a user material subroutine in Abaqus ? a commercially available finite element software package. The model is formulated in terms of finite deformations and assumes the SMP behaves as a thermoelastic material, for which the response is modeled using a compressible neo-Hookean constitutive equation. An internal state variable, the glassy volume fraction, is introduced to account for the phase transformation and associated stored deformation upon cooling from the rubbery phase to the glassy phase and subsequently recovered upon heating. The numerical implementation is performed such that a system of equations is solved using a Newton-Raphson method to find the updated stress in the material. The conductive heat transfer is incorporated through solving Fourier's law simultaneously with the constitutive equations. To calibrate and validate the model parameters, thermomechanical experiments are performed on an amorphous, thermosetting polyurethane shape memory polymer. Strains of 10-25% are applied and both free recovery (zero load) and constrained displacement recovery boundary conditions are considered for each value of applied strain. Using the uniaxial experimental data, the model is then calibrated and compared to the 1-D experimental results. The validated finite element analysis tool is then used to model biomedical devices, including cardiovascular tubes and thrombectomy devices, fabricated from shape memory polymers. The effects of heat transfer and complex thermal boundary conditions are evaluated using coupled thermal-displacement analysis, for which the thermal material properties were experimentally calibrated.

Volk, Brent 1985-

2012-12-01T23:59:59.000Z

242

Accuracy Analysis of a Spectral Element Atmospheric Model Using a Fully Implicit Solution Framework  

Science Conference Proceedings (OSTI)

A fully implicit (FI) time integration method has been implemented into a spectral finite-element shallow-water equation model on a sphere, and it is compared to existing fully explicit leapfrog and semi-implicit methods for a suite of test ...

Katherine J. Evans; Mark A. Taylor; John B. Drake

2010-08-01T23:59:59.000Z

243

Neutron Flux Interpolation with Finite Element Method in the Nuclear Fuel Cell Calculation using Collision Probability Method  

SciTech Connect

Nuclear reactor design and analysis of next-generation reactors require a comprehensive computing which is better to be executed in a high performance computing. Flat flux (FF) approach is a common approach in solving an integral transport equation with collision probability (CP) method. In fact, the neutron flux distribution is not flat, even though the neutron cross section is assumed to be equal in all regions and the neutron source is uniform throughout the nuclear fuel cell. In non-flat flux (NFF) approach, the distribution of neutrons in each region will be different depending on the desired interpolation model selection. In this study, the linear interpolation using Finite Element Method (FEM) has been carried out to be treated the neutron distribution. The CP method is compatible to solve the neutron transport equation for cylindrical geometry, because the angle integration can be done analytically. Distribution of neutrons in each region of can be explained by the NFF approach with FEM and the calculation results are in a good agreement with the result from the SRAC code. In this study, the effects of the mesh on the k{sub eff} and other parameters are investigated.

Shafii, M. Ali [Departmen of Physics Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40134 (Indonesia); Physics Department, Andalas University, Kampus Limau Manis, Padang, Sumatera Barat (Indonesia); Su'ud, Zaki; Waris, Abdul; Kurniasih, Neny [Departmen of Physics Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40134 (Indonesia); Ariani, Menik [Physics Department, Sriwijaya University, Kampus Indralaya, Ogan Ilir, Sumatera Selatan (Indonesia); Departmen of Physics Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40134 (Indonesia); Yulianti, Yanti [Physics Department, Lampung University, Jl.Sumantri Brojonegoro no 1, Lampung (Indonesia); Departmen of Physics Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40134 (Indonesia)

2010-12-23T23:59:59.000Z

244

Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients  

Science Conference Proceedings (OSTI)

This thesis presents a two-grid algorithm based on Smoothed Aggregation Spectral Element Agglomeration Algebraic Multigrid (SA-{rho}AMGe) combined with adaptation. The aim is to build an efficient solver for the linear systems arising from discretization of second-order elliptic partial differential equations (PDEs) with stochastic coefficients. Examples include PDEs that model subsurface flow with random permeability field. During a Markov Chain Monte Carlo (MCMC) simulation process, that draws PDE coefficient samples from a certain distribution, the PDE coefficients change, hence the resulting linear systems to be solved change. At every such step the system (discretized PDE) needs to be solved and the computed solution used to evaluate some functional(s) of interest that then determine if the coefficient sample is acceptable or not. The MCMC process is hence computationally intensive and requires the solvers used to be efficient and fast. This fact that at every step of MCMC the resulting linear system changes, makes an already existing solver built for the old problem perhaps not as efficient for the problem corresponding to the new sampled coefficient. This motivates the main goal of our study, namely, to adapt an already existing solver to handle the problem (with changed coefficient) with the objective to achieve this goal to be faster and more efficient than building a completely new solver from scratch. Our approach utilizes the local element matrices (for the problem with changed coefficients) to build local problems associated with constructed by the method agglomerated elements (a set of subdomains that cover the given computational domain). We solve a generalized eigenproblem for each set in a subspace spanned by the previous local coarse space (used for the old solver) and a vector, component of the error, that the old solver cannot handle. A portion of the spectrum of these local eigen-problems (corresponding to eigenvalues close to zero) form the coarse basis used to define the new two-level method of our interest. We illustrate the performance of this adaptive two-level procedure with a large set of numerical experiments that demonstrate its efficiency over building the solvers from scratch.

Kalchev, D

2012-04-02T23:59:59.000Z

245

Abstract A COUPLED CFD FINITE ELEMENT ANALYSIS METHODOLOGY IN A BIFURCATION PIPE IN A NUCLEAR PLANT HEAT EXCHANGER  

E-Print Network (OSTI)

The accurate calculation of temperature distribution in key parts of a nuclear plant plays a crucial role in maximising the power output and the plant efficiency, whilst ensuring safe operation. The need for making the most profitable use of the available sources of energy requires the full exploitation of plant operational capacity. Temperature dependent material properties mean that increasing the power output in a nuclear plant may reduce the life of the welds in the pipes of the heat exchanger (boiler), operating in very demanding conditions. Rolls-Royce plc was requested to come up with a suitable solution that shielded critical pipe weld locations, reducing local temperatures, so allowing a useful increase in power output from the plant. Part of the heat shield design process was a comprehensive thermal analysis of the installation. Traditionally fluid and solid simulations are conducted separately or using conjugate analysis. Standard methods rely on the application of boundary conditions to the wall surface, which are commonly based on empirical heat transfer coefficient correlations or approximate read across of the CFD results. An alternative approach using conjugate calculations can be adopted, but the computational cost and meshing difficulties in matching the fluid and solid grids makes this unaffordable in terms of analysis time. This paper presents the application of an improved method using a communication library (SC89) between the in-house finite element (FE) code SC03, and the commercial computational fluid dynamics (CFD) code FLUENT. The method has been validated using test data from a Perspex model, where heat transfer coefficients were measured using a transient liquid crystal technique.

J. A. Dixon; A. Guijarro Valencia; P. Irel; P. Ridl; N. Hills

2010-01-01T23:59:59.000Z

246

Grid size convergence study of the finite-element method applied to electron, positron-molecule scattering  

SciTech Connect

The convergence of the fifth order Hermite polynomial, Finite Element method is studied for electron and positron scattering from N{sub 2} and C{sub 2}H{sub 2} in the static approximation in spherical coordinates. Results are compared with a single-center method employing spherical harmonic expansions in order to compare grid size requirements to number of partial waves in the single-center method. Results will be presented at the level of phase shifts, integrated and differential cross sections.

Weatherford, C.A.; Khurana, I.

1993-05-01T23:59:59.000Z

247

The robust estimation method for a finite mixture of Poisson mixed-effect models  

Science Conference Proceedings (OSTI)

When analyzing clustered count data derived from several latent subpopulations, the finite mixture of the Poisson mixed-effect model is an immediate strategy to model the underlying heterogeneity. Within the generalized linear mixed model framework, ... Keywords: Finite mixture, Minimum Hellinger distance, Non-parametric maximum likelihood, Robustness

Liming Xiang; Kelvin K. W. Yau; Andy H. Lee

2012-06-01T23:59:59.000Z

248

A Finite Mixture Logit Model to Segment and Predict Electronic Payments System Adoption  

Science Conference Proceedings (OSTI)

Despite much hype about electronic payments systems (EPSs), a 2004 survey establishes that close to 80% of between-business payments are still made using paper-based formats. We present a finite mixture logit model to predict likelihood of EPS adoption ... Keywords: clustering analysis, electronic payments systems, finite mixture model, hierarchical logit regression, logistic regression, market segmentation

Ravi Bapna; Paulo Goes; Kwok Kee Wei; Zhongju Zhang

2011-03-01T23:59:59.000Z

249

Automated quadrilateral surface discretization method and apparatus usable to generate mesh in a finite element analysis system  

DOE Patents (OSTI)

An automatic quadrilateral surface discretization method and apparatus is provided for automatically discretizing a geometric region without decomposing the region. The automated quadrilateral surface discretization method and apparatus automatically generates a mesh of all quadrilateral elements which is particularly useful in finite element analysis. The generated mesh of all quadrilateral elements is boundary sensitive, orientation insensitive and has few irregular nodes on the boundary. A permanent boundary of the geometric region is input and rows are iteratively layered toward the interior of the geometric region. Also, an exterior permanent boundary and an interior permanent boundary for a geometric region may be input and the rows are iteratively layered inward from the exterior boundary in a first counter clockwise direction while the rows are iteratively layered from the interior permanent boundary toward the exterior of the region in a second clockwise direction. As a result, a high quality mesh for an arbitrary geometry may be generated with a technique that is robust and fast for complex geometric regions and extreme mesh gradations.

Blacker, Teddy D. (12205 Kashmir, N.E., Albuquerque, NM 87111)

1994-01-01T23:59:59.000Z

250

Two-dimensional nonlinear finite element analysis of well damage due to reservoir compaction, well-to-well interactions, and localization on weak layers  

Science Conference Proceedings (OSTI)

In this paper the authors present the results of a coupled nonlinear finite element geomechanics model for reservoir compaction and well-to-well interactions for the high-porosity, low strength diatomite reservoirs of the Belridge field near Bakersfield, California. They show that well damage and failures can occur under the action of two distinct mechanisms: shear deformations induced by pore compaction, and subsidence, and shear deformations due to well-to-well interactions during production or water injection. They show such casting damage or failure can be localized to weak layers that slide or slip under shear due to subsidence. The magnitude of shear displacements and surface subsidence agree with field observations.

Hilbert, L.B. Jr. [Univ. of California, Berkeley, CA (United States); Fredrich, J.T. [Sandia National Labs., Albuquerque, NM (United States); Bruno, M.S. [Terralog Technologies USA, Inc., Arcadia, CA (United States); Deitrick, G.L.; Rouffignac, E.P. de [Shell Exploration and Production Co., Houston, TX (United States)

1996-05-01T23:59:59.000Z

251

Grid-based methods for diatomic quantum scattering problems: a finite-element, discrete variable representation in prolate spheroidal coordinates  

SciTech Connect

We show how to combine finite elements and the discrete variable representation in prolate spheroidal coordinates to develop a grid-based approach for quantum mechanical studies involving diatomic molecular targets. Prolate spheroidal coordinates are a natural choice for diatomic systems and have been used previously in a variety of bound-state applications. The use of exterior complex scaling in the present implementation allows for a transparently simple way of enforcing Coulomb boundary conditions and therefore straightforward application to electronic continuum problems. Illustrative examples involving the bound and continuum states of H2+, as well as the calculation of photoionization cross sections, show that the speed and accuracy of the present approach offer distinct advantages over methods based on single-center expansions.

Tao, Liang; McCurdy, C.W.; Rescigno, T.N.

2008-11-25T23:59:59.000Z

252

GEOTHERM: A finite difference code for testing metamorphic P-T-t paths and tectonic models  

Science Conference Proceedings (OSTI)

Here, time-dependent solutions for the heat conduction equation are numerically evaluated in 1D space using a fully implicit algorithm based on the finite difference method, assuming temperature-dependence of thermal conductivity. The method is implemented ... Keywords: Finite differences methods, HT Metamorphism, Numerical modeling, P-T-t paths, Variscan

Leonardo Casini, Antonio Puccini, Stefano Cuccuru, Matteo Maino, Giacomo Oggiano

2013-09-01T23:59:59.000Z

253

Modeling complex wells with the multi-scale finite-volume method  

Science Conference Proceedings (OSTI)

In this paper, an extension of the multi-scale finite-volume (MSFV) method is devised, which allows to simulate flow and transport in reservoirs with complex well configurations. The new framework fits nicely into the data structure of the original MSFV ... Keywords: Gravity, Heterogeneous media, Multi-phase flow, Multi-scale finite-volume, Porous media, Well modeling

Patrick Jenny; Ivan Lunati

2009-02-01T23:59:59.000Z

254

Pollution error in the h-version of the finite-element method and the local quality of a-posteriori error estimators  

E-Print Network (OSTI)

In this work we study the pollution-error in the h-version of the finite element method and its effect on the local quality of a-posteriori error estimators. We show that the pollution-effect in an interior subdomain depends on the relationship between the mesh inside and outside the subdomain and the smoothness of the exact solution. We also demonstrate that it is possible to guarantee the quality of local error-estimators in the interior of a finite-element mesh-subdomain of interest by employing meshes which are sufficiently refined outside the subdomain.

Mathur, Anuj

1994-01-01T23:59:59.000Z

255

Finite element analysis of elastohydrodynamic circular journal bearing with micropolar lubricants  

Science Conference Proceedings (OSTI)

In this paper the effect of deformation of the bearing liner on the static characteristics of a circular journal bearing operating with micropolar fluid is analysed. Lubricating oil containing additives and contaminants is modeled as micropolar fluid. ... Keywords: deformation coefficient, elastohydrodynamic, micropolar lubricant

V. P. Sukumaran Nair; K. Prabhakaran Nair

2004-10-01T23:59:59.000Z

256

Finite-geometry models of electric field noise from patch potentials in ion traps  

E-Print Network (OSTI)

We model electric field noise from fluctuating patch potentials on conducting surfaces by taking into account the finite geometry of the ion trap electrodes to gain insight into the origin of anomalous heating in ion traps. ...

Low, Guang Hao

257

Application of Fourth-Order Finite Differencing to the NMC Nested Grid Model  

Science Conference Proceedings (OSTI)

A simple algorithm to modify the National Meteorological Center (NMC) Nested Grid Model (NGM) from second-order finite differencing and interpolation on a staggered grid to fourth order is derived and evaluated for operational application. A ...

1992-08-01T23:59:59.000Z

258

Finite volume methods for unidirectional dispersive wave models  

E-Print Network (OSTI)

We extend the framework of the finite volume method to dispersive unidirectional water wave propagation in one space dimension. In particular we consider a KdV-BBM type equation. Explicit and IMEX Runge-Kutta type methods are used for time discretizations. The fully discrete schemes are validated by direct comparisons to analytic solutions. Invariants conservation properties are also studied. Main applications include important nonlinear phenomena such as dispersive shock wave formation, solitary waves and their various interactions.

Dutykh, Denys; Mitsotakis, Dimitrios

2010-01-01T23:59:59.000Z

259

Materials Science and Engineering B 117 (2005) 5361 Finite element analysis-based design of a fluid-flow control nano-valve  

E-Print Network (OSTI)

of a fluid-flow control nano-valve M. Grujicica,, G. Caoa, B. Pandurangana, W.N. Royb a Department A finite element method-based procedure is developed for the design of molecularly functionalized nano-size devices. The procedure is aimed at the single-walled carbon nano-tubes (SWCNTs) used in the construction

Grujicic, Mica

260

Finite-element analysis of the deformation of thin Mylar films due to measurement forces.  

Science Conference Proceedings (OSTI)

Significant deformation of thin films occurs when measuring thickness by mechanical means. This source of measurement error can lead to underestimating film thickness if proper corrections are not made. Analytical solutions exist for Hertzian contact deformation, but these solutions assume relatively large geometries. If the film being measured is thin, the analytical Hertzian assumptions are not appropriate. ANSYS is used to model the contact deformation of a 48 gauge Mylar film under bearing load, supported by a stiffer material. Simulation results are presented and compared to other correction estimates. Ideal, semi-infinite, and constrained properties of the film and the measurement tools are considered.

Baker, Michael Sean; Robinson, Alex Lockwood; Tran, Hy D.

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Adaptive Mesh Refinement Solution Techniques for the Multigroup SN Transport Equation Using a Higher-Order Discontinuous Finite Element Method  

E-Print Network (OSTI)

In this dissertation, we develop Adaptive Mesh Refinement (AMR) techniques for the steady-state multigroup SN neutron transport equation using a higher-order Discontinuous Galerkin Finite Element Method (DGFEM). We propose two error estimations, a projection-based estimator and a jump-based indicator, both of which are shown to reliably drive the spatial discretization error down using h-type AMR. Algorithms to treat the mesh irregularity resulting from the local refinement are implemented in a matrix-free fashion. The DGFEM spatial discretization scheme employed in this research allows the easy use of adapted meshes and can, therefore, follow the physics tightly by generating group-dependent adapted meshes. Indeed, the spatial discretization error is controlled with AMR for the entire multigroup SNtransport simulation, resulting in group-dependent AMR meshes. The computing efforts, both in memory and CPU-time, are significantly reduced. While the convergence rates obtained using uniform mesh refinement are limited by the singularity index of transport solution (3/2 when the solution is continuous, 1/2 when it is discontinuous), the convergence rates achieved with mesh adaptivity are superior. The accuracy in the AMR solution reaches a level where the solution angular error (or ray effects) are highlighted by the mesh adaptivity process. The superiority of higherorder calculations based on a matrix-free scheme is verified on modern computing architectures. A stable symmetric positive definite Diffusion Synthetic Acceleration (DSA) scheme is devised for the DGFEM-discretized transport equation using a variational argument. The Modified Interior Penalty (MIP) diffusion form used to accelerate the SN transport solves has been obtained directly from the DGFEM variational form of the SN equations. This MIP form is stable and compatible with AMR meshes. Because this MIP form is based on a DGFEM formulation as well, it avoids the costly continuity requirements of continuous finite elements. It has been used as a preconditioner for both the standard source iteration and the GMRes solution technique employed when solving the transport equation. The variational argument used in devising transport acceleration schemes is a powerful tool for obtaining transportconforming diffusion schemes. xuthus, a 2-D AMR transport code implementing these findings, has been developed for unstructured triangular meshes.

Wang, Yaqi

2009-05-01T23:59:59.000Z

262

User's Manual for the FEHM Application-A Finite-Element Heat- and Mass-Transfer Code  

DOE Green Energy (OSTI)

This document is a manual for the use of the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multicomponent flow in porous media. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved in the FEHM application by using the finite-element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat- and mass-transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. In fact, FEHM is capable of describing flow that is dominated in many areas by fracture and fault flow, including the inherently three-dimensional flow that results from permeation to and from faults and fractures. The code can handle coupled heat and mass-transfer effects, such as boiling, dryout, and condensation that can occur in the near-field region surrounding the potential repository and the natural convection that occurs through Yucca Mountain due to seasonal temperature changes. The code is also capable of incorporating the various adsorption mechanisms, ranging from simple linear relations to nonlinear isotherms, needed to describe the very complex transport processes at Yucca Mountain. This report outlines the uses and capabilities of the FEHM application, initialization of code variables, restart procedures, and error processing. The report describes all the data files, the input data, including individual input records or parameters, and the various output files. The system interface is described, including the software environment and installation instructions. Examples illustrating various aspects of the code are sprinkled throughout the report, and the final section demonstrates how to construct an input file, shows typical code execution, and gives three examples: heat conduction in a square, a reactive-transport problem, and Problem 5, Case of the DOE Code Comparison Project.

George A. Zyvoloski; Bruce A. Robinson; Zora V. Dash; Lynn L. Trease

1997-07-07T23:59:59.000Z

263

Discrete element modeling of machine-manure interactions  

Science Conference Proceedings (OSTI)

The discrete element method (DEM) was applied to the study of the machine-product interactions occurring in manure handling and land application equipment. Two types of conveying systems (scraper and 4-auger system) were modeled along with a hopper and ... Keywords: Conveying systems, Discrete element method (DEM), Flow rate, Manure, Numerical modeling, Specific energy, Spreader

H. Landry; C. Lagu; M. Roberge

2006-06-01T23:59:59.000Z

264

Parallel Finite Element Electron-Photon Transport Analysis on 2-D Unstructured Mesh  

Science Conference Proceedings (OSTI)

A computer code has been developed to solve the linear Boltzmann transport equation on an unstructured mesh of triangles, from a Pro/E model. An arbitriwy arrangement of distinct material regions is allowed. Energy dependence is handled by solving over an arbitrary number of discrete energy groups. Angular de- pendence is treated by Legendre-polynomial expansion of the particle cross sections and a discrete ordinates treatment of the particle fluence. The resulting linear system is solved in parallel with a preconditioned conjugate-gradients method. The solution method is unique, in that the space-angle dependence is solved si- multaneously, eliminating the need for the usual inner iterations. Electron cross sections are obtained from a Goudsrnit-Saunderson modifed version of the CEPXS code. A one-dimensional version of the code has also been develop@ for testing and development purposes.

Drumm, C.R.

1999-01-01T23:59:59.000Z

265

Blunt-crack band propagation in finite-element analysis for concrete structures. [LMFBR  

SciTech Connect

The knowledge of concrete fracture is needed in nuclear reactor safety. The question of safety arises from the potential of concrete to crack under thermal loading. It has been postulated that structural concrete could be exposed to very high temperature, which may result from hot reactor coolant or even core debris coming in direct contact with the concrete. The utilization of the blunt crack approach for simulating concrete cracking in a general-purpose code is explored. The difficulties encountered in establishing the proper direction of crack propagation in an arbitrary discretization are described. Crack propagation is considered within the context of two types of solution techniques: (1) implicit solution of the static crack advance, and (2) explicit time integration using a dynamic relaxation technique to simulate the static crack advance. Also, in both solution techniques an elastic model is used to characterize the concrete.

Pfeiffer, P.A.; Bazant, Z.P.; Marchertas, A.H.

1983-01-01T23:59:59.000Z

266

Partition-of-unity finite-element method for large scale quantum molecular dynamics on massively parallel computational platforms  

Science Conference Proceedings (OSTI)

Over the course of the past two decades, quantum mechanical calculations have emerged as a key component of modern materials research. However, the solution of the required quantum mechanical equations is a formidable task and this has severely limited the range of materials systems which can be investigated by such accurate, quantum mechanical means. The current state of the art for large-scale quantum simulations is the planewave (PW) method, as implemented in now ubiquitous VASP, ABINIT, and QBox codes, among many others. However, since the PW method uses a global Fourier basis, with strictly uniform resolution at all points in space, and in which every basis function overlaps every other at every point, it suffers from substantial inefficiencies in calculations involving atoms with localized states, such as first-row and transition-metal atoms, and requires substantial nonlocal communications in parallel implementations, placing critical limits on scalability. In recent years, real-space methods such as finite-differences (FD) and finite-elements (FE) have been developed to address these deficiencies by reformulating the required quantum mechanical equations in a strictly local representation. However, while addressing both resolution and parallel-communications problems, such local real-space approaches have been plagued by one key disadvantage relative to planewaves: excessive degrees of freedom (grid points, basis functions) needed to achieve the required accuracies. And so, despite critical limitations, the PW method remains the standard today. In this work, we show for the first time that this key remaining disadvantage of real-space methods can in fact be overcome: by building known atomic physics into the solution process using modern partition-of-unity (PU) techniques in finite element analysis. Indeed, our results show order-of-magnitude reductions in basis size relative to state-of-the-art planewave based methods. The method developed here is completely general, applicable to any crystal symmetry and to both metals and insulators alike. We have developed and implemented a full self-consistent Kohn-Sham method, including both total energies and forces for molecular dynamics, and developed a full MPI parallel implementation for large-scale calculations. We have applied the method to the gamut of physical systems, from simple insulating systems with light atoms to complex d- and f-electron systems, requiring large numbers of atomic-orbital enrichments. In every case, the new PU FE method attained the required accuracies with substantially fewer degrees of freedom, typically by an order of magnitude or more, than the current state-of-the-art PW method. Finally, our initial MPI implementation has shown excellent parallel scaling of the most time-critical parts of the code up to 1728 processors, with clear indications of what will be required to achieve comparable scaling for the rest. Having shown that the key remaining disadvantage of real-space methods can in fact be overcome, the work has attracted significant attention: with sixteen invited talks, both domestic and international, so far; two papers published and another in preparation; and three new university and/or national laboratory collaborations, securing external funding to pursue a number of related research directions. Having demonstrated the proof of principle, work now centers on the necessary extensions and optimizations required to bring the prototype method and code delivered here to production applications.

Pask, J E; Sukumar, N; Guney, M; Hu, W

2011-02-28T23:59:59.000Z

267

Finite element analyses of continuous filament ties for masonry applications:final report for the Arquin Corporation.  

Science Conference Proceedings (OSTI)

Finite-element analyses were performed to simulate the response of a hypothetical masonry shear wall with and without continuous filament ties to various lateral loads. The loads represented three different scenarios: (1) 100 mph wind, (2) explosive attack, and (3) an earthquake. In addition, a static loading analysis and cost comparison were performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Results of the shear-wall loading simulations revealed that simulated walls with the continuous filament ties yielded factors of safety that were at least ten times greater than those without the ties. In the explosive attack simulation (100 psi), the simulated wall without the ties failed (minimum factor of safety was less than one), but the simulated wall with the ties yielded a minimum factor of safety greater than one. Simulations of the walls subject to lateral loads caused by 100 mph winds (0.2 psi) and seismic events with a peak ground acceleration of 1 ''g'' (0.66 psi) yielded no failures with or without the ties. Simulations of wall displacement during the seismic scenarios showed that the wall with the ties resulted in a maximum displacement that was 20% less than the wall without the ties.

Quinones, Armando (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei

2006-06-01T23:59:59.000Z

268

Finite Element Solution of the Self-Adjoint Angular Flux Equation for Coupled Electron-Photon Transport  

SciTech Connect

A novel approach is proposed for charged particle transport calculations using a recently developed second-order, self-adjoint angular flux (SAAF) form of the Boltzmann transport equation with continuous slowing-down. A finite element discretization that is linear continuous in space and linear discontinuous (LD) in energy is described and implemented in a one-dimensional, planar geometry, multigroup, discrete ordinates code for charged particle transport. The cross-section generating code CEPXS is used to generate the electron and photon transport cross sections employed in this code. The discrete ordinates SAAF transport equation is solved using source iteration in conjunction with an inner iteration acceleration scheme and an outer iteration acceleration scheme. Outer iterations are required with the LD energy discretization scheme because the two angular flux unknowns within each group are coupled, which gives rise to effective upscattering. The inner iteration convergence is accelerated using diffusion synthetic acceleration, and the outer iteration convergence is accelerated using a diamond difference approximation to the LD energy discretization. Computational results are given that demonstrate the effectiveness of our convergence acceleration schemes and the accuracy of our discretized SAAF equation.

Liscum-Powell, Jennifer L. [Sandia National Laboratories (United States); Prinja, Anil B. [University of New Mexico (United States); Morel, Jim E. [Los Alamos National Laboratory (United States); Lorence, Leonard J Jr. [Sandia National Laboratories (United States)

2002-11-15T23:59:59.000Z

269

Interfacial temperature measurements, high-speed visualization and finite-element simulations of droplet impact and evaporation on a solid surface  

E-Print Network (OSTI)

The objective of this work is to investigate the coupling of fluid dynamics, heat transfer and mass transfer during the impact and evaporation of droplets on a heated solid substrate. A laser-based thermoreflectance method is used to measure the temperature at the solid-liquid interface, with a time and space resolution of 100 {\\mu}s and 20 {\\mu}m, respectively. Isopropanol droplets with micro- and nanoliter volumes are considered. A finite-element model is used to simulate the transient fluid dynamics and heat transfer during the droplet deposition process, considering the dynamics of wetting as well as Laplace and Marangoni stresses on the liquid-gas boundary. For cases involving evaporation, the diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary condition for the evaporative flux at the droplet-air interface. High-speed visualizations are performed to provide matching parameters for the wetting model used in the simulations. Numerical and experimental results are compar...

Bhardwaj, Rajneesh; Attinger, Daniel

2010-01-01T23:59:59.000Z

270

Finite Element-Based  

Science Conference Proceedings (OSTI)

Analyzing Upper Tails of Grain Size Distributions Using Extreme Value ... Strain Gradient and Degradation in Magnetic Properties: Focus Transformer Steel.

271

Notes 01. Modeling of mechanical (lumped parameter) elements  

E-Print Network (OSTI)

Fundamental elements in mechanical systems: inertias, stiffness and damping elements. Equivalent spring coefficients and associated potential energy. Equivalent mass or inertia coefficients and associated kinetic energy. Equations of motion of a rigid body in a plane. Equivalent damping coefficients and associated dissipation energy. Types of damping models (linear or viscous and nonlinear).

San Andres, Luis

2008-01-01T23:59:59.000Z

272

Constraints of mixing matrix elements in the sequential fourthgeneration model  

E-Print Network (OSTI)

We review our works on the sequential fourth generation model and focus on the constriants of $4\\times 4$ quark mixing matrix elements. We investigate the quark mixing matrix elements from the rare $K,B$ meson decays. We talk about the $ hierarchy$ of the $4\\times 4$ matrix and the existence of fourth generation.

Huo, W J

2002-01-01T23:59:59.000Z

273

Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks  

E-Print Network (OSTI)

A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.

S. Athanassopoulos; E. Mavrommatis; K. A. Gernoth; J. W. Clark

2005-11-30T23:59:59.000Z

274

Hypercube performance for 2-D seismic finite-difference modeling  

Science Conference Proceedings (OSTI)

Wave-equation seismic modeling in two space dimensions is computationally intensive, often requiring hours of supercomputer CPU time to run typical geological models with 500 500 grids and 100 sources. This paper analyzes the performance of ACOUS2D, ...

L. J. Baker

1989-01-01T23:59:59.000Z

275

Four-Layer Models of Finite-Amplitude Baroclinic Waves  

Science Conference Proceedings (OSTI)

A linear stability analysis is performed for a four-layer quasi-geostrophic model of zonally uniform flow in a channel. Models are then constructed to correspond with the continuous models of Green (1960), Gill et al. (1974), and the four-level ...

John Francis Donahue

1980-02-01T23:59:59.000Z

276

Finite element simulation for ultraviolet excimer laser processing of patterned Si/SiGe/Si(100) heterostructures  

SciTech Connect

Ultraviolet (UV) Excimer laser assisted processing is an alternative strategy for producing patterned silicon germanium heterostructures. We numerically analyzed the effects caused by pulsed 193 Excimer laser radiation impinging on patterned amorphous hydrogenated silicon (a-Si:H) and germanium (a-Ge:H) bilayers deposited on a crystalline silicon substrate [Si(100)]. The proposed two dimensional axisymmetric numerical model allowed us to estimate the temperature and concentration gradients caused by the laser induced rapid melting and solidification processes. Energy density dependence of maximum melting depth and melting time evolution as well as three dimensional temperature and element distribution have been simulated and compared with experimentally obtained results.

Conde, J. C.; Chiussi, S.; Gontad, F.; Gonzalez, P. [Dpto. Fisica Aplicada, University of Vigo, E-36310 Vigo (Spain); Martin, E. [Dpto. Mecanica, Maquinas, Motores Termicos y Fluidos, University of Vigo, E-36310 Vigo (Spain); Serra, C. [CACTI, University of Vigo, E-36310 Vigo (Spain)

2010-07-05T23:59:59.000Z

277

Electron-H{sub 2}{sup +} scattering using the finite-element method with iterative-variational solution of the algebraic problem  

Science Conference Proceedings (OSTI)

Coulomb Sturmians are used to calculate the ground state of H{sub 2}{sup +}. The required multicenter integrals are calculated to very high accuracy in momentum space. Differential cross sections describing electron scattering from the ground state of H{sub 2}{sup +} are then calculated using the finite element method. The solution of the resulting linear algebraic problem is accomplished using the iterative-variational method.

Weatherford, C.A.

1993-12-01T23:59:59.000Z

278

A dimensionally reduced finite mixture model for multilevel data  

Science Conference Proceedings (OSTI)

Recently, different mixture models have been proposed for multilevel data, generally requiring the local independence assumption. In this work, this assumption is relaxed by allowing each mixture component at the lower level of the hierarchical structure ... Keywords: Cluster analysis, Dimension reduction, EM-algorithm, Factor mixture model, Multilevel latent class analysis, primary, secondary

Daniela G. Cal; Cinzia Viroli

2010-11-01T23:59:59.000Z

279

Discrete-element model for the interaction between ocean waves and sea ice  

SciTech Connect

We present a discrete element method (DEM) model to simulate the mechanical behavior of sea ice in response to ocean waves. The wave/ice interaction can potentially lead to the fracture and fragmentation of sea ice depending on the wave amplitude and period. The fracture behavior of sea ice is explicitly modeled by a DEM method, where sea ice is modeled by densely packed spherical particles with finite size. These particles are bonded together at their contact points through mechanical bonds that can sustain both tensile & compressive forces and moments. Fracturing can be naturally represented by the sequential breaking of mechanical bonds. For a given amplitude and period of incident ocean wave, the model provides information for the spatial distribution and time evolution of stress and micro-fractures and the fragment size distribution. We demonstrate that the fraction of broken bonds,, increases with increasing wave amplitude. In contrast, the ice fragment size decreases with increasing amplitude.

Xu, Zhijie; Tartakovsky, Alexandre M.; Pan, Wenxiao

2012-01-05T23:59:59.000Z

280

Comparison between LQCD and PNJL model at finite chemical potentials  

E-Print Network (OSTI)

Lattice QCD has the sign problem at real quark chemical potential. There are some regions with no sign problem; one is the imaginary quark chemical potential region and the others are the real and imaginary isospin chemical potential regions. We show that the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model can reproduce LQCD data in the regions. We also determine the model parameters from the data and predict the QCD phase diagram in the real quark chemical potential region.

Sakai, Yuji; Kouno, Hiroaki; Yahiro, Masanobu

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Physical Model Explaining the Periodic Pattern of the Chemical Elements  

E-Print Network (OSTI)

The fundamental organizing principle resulting in the periodic table is the nuclear charge. Arranging the chemical elements in an increasing atomic number order, a symmetry pattern known as the Periodic Table is detectable. The correlation between nuclear charge and the Periodic System of the Chemical Elements (PSCE) indicates that the symmetry emerges from the nucleus. Nuclear symmetry can only be developed if the positions of the nucleons are preserved. Thus the phase of the nucleus must be solid where the positions of the nucleons are preserved in a lattice. A lattice model, representing the protons and the neutrons by equal spheres and arranging them alternately in a face centered cubic structure forming a double tetrahedron, is able to reproduce all of the properties of the nucleus including the quantum numbers and the periodicity of the elements. Using this nuclear structure model, an attempt is made here to give a physical explanation for the periodicity of the chemical elements.

Jozsef Garai

2011-01-24T23:59:59.000Z

282

Meson properties in a nonlocal SU(3) chiral quark model at finite temperature  

SciTech Connect

Finite temperature meson properties are studied in the context of a nonlocal SU(3) quark model which includes flavor mixing and the coupling of quarks to the Polyakov loop (PL). We analyze the behavior of scalar and pseudoscalar meson masses and mixing angles, as well as quark-meson couplings and pseudoscalar meson decay constants.

Contrera, G. A. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Centro Atomico Constituyentes, Buenos Aires (Argentina); Gomez Dumm, D. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2010-11-12T23:59:59.000Z

283

Investigating finite models of non-classical logics with relation algebra and RELVIEW  

Science Conference Proceedings (OSTI)

In computer science, scenarios with interacting agents are often developed using modal logic. We show how to interpret modal logic of knowledge in relation algebra. This allows the use of the RelView tool for the purpose of investigating finite models ...

Rudolf Berghammer; Renate A. Schmidt

2006-01-01T23:59:59.000Z

284

Grid-based methods for diatomic quantum scattering problems: a finite-element, discrete variable representation in prolate spheroidal coordinates  

E-Print Network (OSTI)

parts of the kinetic energy matrix, dropping the surfacew n . The kinetic energy and potential matrix elements are

McCurdy, C.W.

2008-01-01T23:59:59.000Z

285

Finite-temperature spectral function of the vector mesons in a holographic QCD model  

Science Conference Proceedings (OSTI)

We use the soft-wall anti-de Sitter/QCD model to investigate the finite-temperature effects on the spectral function in the vector channel. The dissociation of the vector meson tower onto the anti-de Sitter black hole leads to the in-medium mass shift and the width broadening in a way similar to the lattice QCD results for the heavy quarkonium at finite temperature. We also show the momentum dependence of the spectral function and find it consistent with screening in a hot wind.

Fujita, Mitsutoshi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Fukushima, Kenji; Misumi, Tatsuhiro; Murata, Masaki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2009-08-01T23:59:59.000Z

286

Finite-temperature spectral function of the vector mesons in an AdS/QCD model  

E-Print Network (OSTI)

We use the soft-wall AdS/QCD model to investigate the finite-temperature effects on the spectral function in the vector channel. The dissociation of the vector meson tower onto the AdS black hole leads to the in-medium mass shift and the width broadening in a way similar to the lattice QCD results for the heavy quarkonium at finite temperature. We also show the momentum dependence of the spectral function and find it consistent with screening in a hot wind.

Mitsutoshi Fujita; Kenji Fukushima; Tatsuhiro Misumi; Masaki Murata

2009-03-13T23:59:59.000Z

287

Occupation number and fluctuations in the finite-temperature Bose-Hubbard model  

E-Print Network (OSTI)

We study the occupation numbers and number fluctuations of ultra-cold atoms in deep optical lattices for finite temperatures within the Bose-Hubbard model. Simple analytical expressions for the mean occupation number and number fluctuations are obtained in the weak-hopping regime using an interpolation between results from different perturbation approaches in the Mott-insulator and superfluid phases. These analytical results are compared to exact one dimensional numerical calculations using a finite temperature variant of the Density-Matrix Renormalisation Group (DMRG) method and found to have a high degree of accuracy. We also find very good agreement in the crossover ``thermal'' region. With the present approach the magnitude of number fluctuations under realistic experimental conditions can be estimated and the properties of the finite temperature phase diagram can be studied.

L. I. Plimak; M. Fleischhauer; M. K. Olsen

2003-09-25T23:59:59.000Z

288

Winding Transitions at Finite Energy and Temperature: An O(3) Model  

E-Print Network (OSTI)

Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at low energies, and numerically for all energies up to the sphaleron scale. The Euclidean period beta of these finite energy instantons increases with energy, contrary to the behavior found in the abelian Higgs model or simple one dimensional systems. This results in a sharp crossover from instanton dominated tunneling to sphaleron dominated thermal activation at a certain critical temperature. Since this behavior is traceable to the soft breaking of conformal invariance by the mass term in the sigma model, semiclassical winding number transition amplitudes in the electroweak theory in 3+1 dimensions should exhibit a similar sharp crossover. We argue that this is indeed the case in the standard model for M_H < 4 M_W.

Salman Habib; Emil Mottola; Peter Tinyakov

1996-08-14T23:59:59.000Z

289

Auroral hot-ion dynamo model with finite gyroradii  

Science Conference Proceedings (OSTI)

Discrete auroras have (1) narrow size s(less-or-similar sign)30 km in at least one dimension (e.g., north-south) and (2) often rapid variation of forms, especially where the size is extremely small, s{geomagnetic field lines. The flows (include PSBL) usually have some filamentary structure with transverse widths of a few local gyroradii of the hot protons (kT{approx}1-30 keV), i.e., widths that encompass auroral-arc size when scaled by magnetic field-line separation. At these widths, modest density gradients ({delta}n{approx}0.01-0.1 cm{sup -3}) lead to charge separation by differential mirroring of hot protons and electrons and large perpendicular electric fields. Thermal escape of ionspheric electrons into positive charge layer builds up magnetic field-aligned potential difference that accelerates hot electrons from negative charge layer into the ionosphere within auroral arc thickness. As a corollary, the model delineates a mechanism for charge-driven plasma instabilities.

Lennartsson, O. W. [Advanced Technology Center, Lockheed Martin Space Systems Co., Palo Alto, California 94304 (United States)

2006-07-15T23:59:59.000Z

290

Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature  

Science Conference Proceedings (OSTI)

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.

Gomez Dumm, D., E-mail: dumm@fisica.unlp.edu.ar [UNLP, IFLP, Departamento de Fisica (Argentina); Contrera, G. A., E-mail: contrera@tandar.cnea.gov.ar [CONICET (Argentina)

2012-06-15T23:59:59.000Z

291

An algorithm for transferring 2D arbitrary hp-refined finite element axially symmetric meshes to three dimensions  

E-Print Network (OSTI)

of Petroleum Engineering, The University of Texas in Austin (3) Institute for Computational Engineering and Sciences, ICES, The University of Texas in Austin Abstract The 2D and 3D fully automatic hp adaptive Finite is solved on the coarse and on the fine mesh. The energy norm (H1 Sobolev space norm) difference between

Torres-Verdín, Carlos

292

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including ... Keywords: Aerosols, Aggregation, Particle adhesion, Particulate flow

J. S. Marshall

2009-03-01T23:59:59.000Z

293

Representative element modeling of fracture systems based on stochastic analysis  

DOE Green Energy (OSTI)

An important task associated with reservoir simulation is the development of a technique to model a large number of fractures with a single description. Representative elements must be developed before reservoir scale simulations can adequately address the effects of intersecting fracture systems on fluid migration. An effective element model will sharply reduce the cost and complexity of large scale simulations to bring these to manageable levels. Stochastic analysis is a powerful tool which can determine the hydraulic and transport characteristics of intersecting sets of statistically defined fractures. Hydraulic and transport characteristics are required to develop representative elements. Given an assumption of fully developed laminar flow, the net fracture conductivities and hence flow velocities can be determined from descriptive statistics of fracture spacing, orientation, aperture, and extent. The distribution of physical characteristics about their mean leads to a distribution of the associated conductivities. The variance of hydraulic conductivity induces dispersion into the transport process. The simplest of fracture systems, a single set of parallel fractures, is treated to demonstrate the usefulness of stochastic analysis. Explicit equations for conductivity of an element are developed and the dispersion characteristics are shown. The analysis reveals the dependence of the representative element properties on the various parameters used to describe the fracture system. 10 refs., 3 figs.

Clemo, T.M.

1986-01-01T23:59:59.000Z

294

An Unstructured Grid, Finite-Volume, Three-Dimensional, Primitive Equations Ocean Model: Application to Coastal Ocean and Estuaries  

Science Conference Proceedings (OSTI)

An unstructured grid, finite-volume, three-dimensional (3D) primitive equation ocean model has been developed for the study of coastal oceanic and estuarine circulation. The model consists of momentum, continuity, temperature, salinity, and ...

Changsheng Chen; Hedong Liu; Robert C. Beardsley

2003-01-01T23:59:59.000Z

295

NJL Model at Finite Chemical Potential in a Constant Magnetic Field  

E-Print Network (OSTI)

We investigate the influence of an external magnetic field on chiral symmetry breaking in the Nambu-Jona-Lasinio (NJL) model at finite temperature and chemical potential. According to the Fock-Schwinger proper-time method, we calculate the effective potential in the leading order of the $1/N_c$ expansion. The phase boundary dividing the symmetric phase and the broken phase is illustrated numerically. A complex behavior of the phase boundary is found for large chemical potential.

Tomohiro Inagaki; Daiji Kimura; Tsukasa Murata

2004-04-24T23:59:59.000Z

296

Unstructured finite volume discretisation of bed friction and convective flux in solute transport models linked to the shallow water equations  

Science Conference Proceedings (OSTI)

The finite volume discretisation of the shallow water equations has been the subject of many previous studies, most of which deal with a well-balanced conservative discretisation of the convective flux and bathymetry. However, the bed friction discretisation ... Keywords: Bed friction, Depth averaged models, Finite volume method, High order schemes, Scalar transport, Shallow water equations, Unstructured mesh

L. Cea; M. E. Vzquez-Cendn

2012-04-01T23:59:59.000Z

297

Finite-element analyses of blade and slot coating flows using an implicit pseudo-solid domain mapping technique coupled with unstructured grids  

SciTech Connect

In coating processes (e.g. in blade coating) the flow domain inherently contains free surfaces and three-phase contact lines, and characteristic length scales of flow features in the dimension transverse to the web-movement vary by an order of magnitude or more from a fraction of a millimeter or more to tens of microns or less). The presence of free surfaces and three-phase contact lines, and the sudden changes of flow geometry and directions create difficulties in theoretical analyses of such flows. Though simulations of coating flows via finite-element methods using structured grids have been reportedly demonstrated in the literature, achieving high efficiency of such numerical experiments remains a grand challenge -- mainly due to difficulties in local mesh-refinement and in avoiding unacceptably distorted grids. High efficiency of computing steady flow fields under various process conditions is crucial in shortening turn-around time in design and optimization of coating-flow processes. In this paper we employ a fully-implicit, pseudo-solid, domain mapping technique coupled with unstructured meshes to analyze blade and slot coating flows using Galerkin`s method with finite element basis functions. We demonstrate the robustness and efficiency of our unique technique in circumventing shortcomings of mesh-motion schemes currently being used in the coating-flow research community. Our goal is to develop an efficient numerical tool, together with a suitable optimization toolkit, that can be used routinely in design and optimization of coating-flow processes.

Chen, K.S.; Schunk, P.R.; Sackinger, P.A.

1994-12-04T23:59:59.000Z

298

A Spectral Element Approach for Modeling of Wave-Based Structural Health Monitoring Systems  

Science Conference Proceedings (OSTI)

During the last decades, guided waves have shown great potential for Structural Health Monitoring (SHM) applications. These waves can be excited and sensed by piezoelectric elements that can be permanently attached onto a structure offering online monitoring capability. As the setup of wave based SHM systems may be very difficult and time consuming there is a growing demand for efficient simulation tools providing the opportunity to design wave based SHM systems in a virtual environment. As usually high frequency waves are used, the associated short wavelength leads to the necessity of a very dense mesh, which makes conventional finite elements not well suited for this purpose. Therefore a flat shell spectral element approach is presented in this contribution. By including electromechanical coupling an SHM system can be simulated entirely from actuator voltage to sensor voltage. The focus of this contribution is the analysis of the effect of delaminations on propagating waves. A forward increment Lagrange multiplier method is used to simulate contact within the delaminated area. A model validation is performed using measured data of an anisotropic CFRP-plate.

Schulte, Rolf T.; Fritzen, Claus-Peter [Institute of Mechanics and Control-Mechatronics, University of Siegen, Paul-Bonatz-Str. 9-11, 57076 Siegen (Germany)

2010-09-30T23:59:59.000Z

299

Possibility of Skill Forecast Based on the Finite-Time Dominant Linear Solutions for a Primitive Equation Regional Forecast Model  

Science Conference Proceedings (OSTI)

The possibility of using forecast errors originating from the finite-time dominant linear modes for the prediction of forecast skill for a primitive equation regional forecast model is studied. This is similar to the method for skill prediction ...

Tomislava Vuki?evi?

1993-06-01T23:59:59.000Z

300

The North Atlantic Circulation in the Early 1980s-An Estimate from Inversion of a Finite-Difference Model  

Science Conference Proceedings (OSTI)

A finite-difference model of the North Atlantic is constructed for the purpose Of making an estimate of the circulation through an inverse calculation. The database is eclectic, and includes hydrography, oxygen, nutrients current meter and float ...

Franoise Martel; Carl Wunsch

1993-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A Global Multilevel Atmospheric Model Using a Vector Semi-Lagrangian Finite-Difference Scheme. Part II: Version with Physics  

Science Conference Proceedings (OSTI)

Full physical parameterzations have been incorporated into the global model using a two-time-level, semi-Lagrangian, semi-implicit finite-difference integration scheme that was described in Part I of this work. Virtual temperature effects have ...

S. Moorthi; R. W. Higgins; J. R. Bates

1995-05-01T23:59:59.000Z

302

The Constraints of Energy-Conserving Vertical Finite Difference on the Hydrostatic Equations in a NWP Model  

Science Conference Proceedings (OSTI)

In NWP models using energy-conserving finite-difference approximations in the vertical, the imposition of different constraints of the discrete energy equation leads to different forms of the hydrostatic equation. This paper shows, using the ...

Samuel Y. K. Yee

1983-02-01T23:59:59.000Z

303

A Method for Imposing Surface Stress and Heat Flux Conditions in Finite-Difference Models with Steep Terrain  

Science Conference Proceedings (OSTI)

A numerical implementation of the surface stress boundary condition is presented for finite-difference models in which the terrain slope and curvature cannot necessarily be considered small. The method involves reducing the discretized stress ...

C. C. Epifanio

2007-03-01T23:59:59.000Z

304

The problem of an obducting lithospheric plate in the Aleutian arc system. A finite element analysis in the frictionless case  

Science Conference Proceedings (OSTI)

A model of the Aleutian arc system is studied from the point of view of a plate tectonic concept based on the global geodynamic model. In our model problem we limit ourselves to a model in which the lithospheric plate is obducting with time onto the ...

J. Nedoma; J. Haslinger; I. Hlavek

1989-01-01T23:59:59.000Z

305

Phased Nonlinear Finite-Element Analysis of Precracked RC T-Beams Repaired in Shear with CFRP Sheets  

E-Print Network (OSTI)

response of the beams to different load histories, provides insight into three alternative constitutive models for the behavior of concrete in shear, and concentrates in particular on modeling the sequence of loading, unloading, repair and reloading... -cracking behavior of concrete was modeled by a linear tension softening model [Eq. (2)] which relates the ultimate concrete tensile strain (?c,ult) to the concrete tensile strength, concrete fracture energy (Gf), and crack bandwidth (hb). tb f c,ult fh G ? 2...

Dirar, Samir; Lees, Janet M.; Morley, Chris

2012-10-17T23:59:59.000Z

306

Modelling and simulation of elements for solar heating and daylighting  

SciTech Connect

Through the development of highly efficient transparent insulation materials (TIM), new opportunities are appearing in the field of daylighting and passive solar space heating. The simulation program WANDSIM, developed at the Fraunhofer-Institut fuer Solare Energiesysteme (ISE), models the dynamic performance of three important elements for daylighting and passive solar space heating; window glazing; transparently insulated masonry; transparently insulated glass wall. Selected simulation results of each type are represented and compared under thermal and daylighting aspects. The advantages of the transparently insulated glass wall, a new combined passive space heating and daylighting system, in economy and comfort are verified.

Wilke, W.S.; Schmid, J. (Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg (West Germany))

1991-01-01T23:59:59.000Z

307

Long Fibre Composite Modelling Using Cohesive User's Element  

Science Conference Proceedings (OSTI)

The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

Kozak, Vladislav; Chlup, Zdenek [Institute of Physics of Material AS of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)

2010-09-30T23:59:59.000Z

308

A Mixed Spectral Finite-Difference 3D Model of Neutral Planetary Boundary-Layer Flow over Topography  

Science Conference Proceedings (OSTI)

A simple three-dimensional linear model of planetary boundary-layer flow is developed based on the Mixed Spectral Finite-Difference model of Beljaars et al. using the full second-order turbulence closure of Launder et al. The model uses a steady-...

Keith W. Ayotte; Peter A. Taylor

1995-10-01T23:59:59.000Z

309

Enforcing elemental mass and energy balances for reduced order models  

Science Conference Proceedings (OSTI)

Development of economically feasible gasification and carbon capture, utilization and storage (CCUS) technologies requires a variety of software tools to optimize the designs of not only the key devices involved (e., g., gasifier, CO{sub 2} adsorber) but also the entire power generation system. High-fidelity models such as Computational Fluid Dynamics (CFD) models are capable of accurately simulating the detailed flow dynamics, heat transfer, and chemistry inside the key devices. However, the integration of CFD models within steady-state process simulators, and subsequent optimization of the integrated system, still presents significant challenges due to the scale differences in both time and length, as well the high computational cost. A reduced order model (ROM) generated from a high-fidelity model can serve as a bridge between the models of different scales. While high-fidelity models are built upon the principles of mass, momentum, and energy conservations, ROMs are usually developed based on regression-type equations and hence their predictions may violate the mass and energy conservation laws. A high-fidelity model may also have the mass and energy balance problem if it is not tightly converged. Conservations of mass and energy are important when a ROM is integrated to a flowsheet for the process simulation of the entire chemical or power generation system, especially when recycle streams are connected to the modeled device. As a part of the Carbon Capture Simulation Initiative (CCSI) project supported by the U.S. Department of Energy, we developed a software framework for generating ROMs from CFD simulations and integrating them with Process Modeling Environments (PMEs) for system-wide optimization. This paper presents a method to correct the results of a high-fidelity model or a ROM such that the elemental mass and energy are conserved perfectly. Correction factors for the flow rates of individual species in the product streams are solved using a minimization algorithm based on Lagrangian multiplier method. Enthalpies of product streams are also modified to enforce the energy balance. The approach is illustrated for two ROMs, one based on a CFD model of an entrained-flow gasifier and the other based on the CFD model of a multiphase CO{sub 2} adsorber.

Ma, J.; Agarwal, K.; Sharma, P.; Lang, Y.; Zitney, S.; Gorton, I.; Agawal, D.; Miller, D.

2012-01-01T23:59:59.000Z

310

Advanced modeling of vertical ground source heat pumps using finite element techniques.  

E-Print Network (OSTI)

??Increasing energy demand and environmental pollution in United States has been led toward using renewable energy sources over recent decades. Ground-source heat pump systems are (more)

Komari Zadeh, Seyed Omid

2011-01-01T23:59:59.000Z

311

Finite Element Model of Training in the superconducting quadrupole magnet SQ02  

E-Print Network (OSTI)

Measur. Fig. 21. Computed and measured training curve.Brechna H, Turowski P. Training and degradation phenomena inmodel and the computed training curve as a tool to compare

Ferracin, Paolo

2009-01-01T23:59:59.000Z

312

Combining a front-tracking model (elle) with the finite element ...  

Science Conference Proceedings (OSTI)

... The example movie shows an analoge experiment using norcamphor and ethanol (analog experiments were done by N. Walte). At room ...

2013-07-05T23:59:59.000Z

313

Nonlinear thermomechanical finite-element modeling, analysis and characterization of multi-turn oscillating heat pipes .  

E-Print Network (OSTI)

??Oscillating heat pipes (OHPs) are promising heat dissipation devices for modern electronic systems due to their high heat transfer rate, simple construction and low manufacturing (more)

Peng, Hao

2012-01-01T23:59:59.000Z

314

Finite-Element Modeling of the Electric Double-Layer and Its ...  

Science Conference Proceedings (OSTI)

... with realistic dimensions, mimicking slit-pore geometries of varying size, and packed spheres similar to ... Designing 3D Conical-Shaped Li-ion Micro-batteries

315

A Variable Resolution Global Model Based upon Fourier and Finite Element Representation  

Science Conference Proceedings (OSTI)

We describe the development and preliminary testing of a numerical scheme designed to predict the global circulation which can also telescope into local subdomains of enhanced vertical and horizontal resolution. The accuracy of the method appears ...

Jan Paegle

1989-03-01T23:59:59.000Z

316

An algorithm for discrete booleans with applications to finite element modeling of complex systems  

Science Conference Proceedings (OSTI)

In this paper we describe a robust algorithm for three-dimensional boolean operations between boundary representation objects whose geometry is given by discrete (faceted) data. The algorithm presents a new approach for computing the intersection graph ... Keywords: Boolean, Discrete, Mesh, Remeshing, Sizing sources, Triangulation

B. Kaan Karamete; Saikat Dey; Eric L. Mestreau; Romain Aubry; Felipe A. Bulat-Jara

2013-06-01T23:59:59.000Z

317

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.

Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu

2009-03-20T23:59:59.000Z

318

Component mode synthesis methods applied to 3D heterogeneous core calculations, using the mixed dual finite element solver MINOS  

Science Conference Proceedings (OSTI)

This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)

Guerin, P.; Baudron, A. M.; Lautard, J. J. [Commissariat a l'Energie Atomique, DEN/DANS/DM2S/SERMA/LENR, CEA Saclay, 91191 Gif sur Yvette (France)

2006-07-01T23:59:59.000Z

319

Meson properties at finite temperature in a three flavor nonlocal chiral quark model with Polyakov loop  

SciTech Connect

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles and decay constants. The critical temperature is found to be T{sub c{approx_equal}}202 MeV, in better agreement with lattice results than the value recently obtained in the local SU(3) PNJL model. It is seen that above T{sub c} pseudoscalar meson masses get increased, becoming degenerate with the masses of their chiral partners. The temperatures at which this matching occurs depend on the strange quark composition of the corresponding mesons. The topological susceptibility shows a sharp decrease after the chiral transition, signalling the vanishing of the U(1){sub A} anomaly for large temperatures.

Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Dumm, D. Gomez [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, Norberto N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, (1078) Buenos Aires (Argentina)

2010-03-01T23:59:59.000Z

320

Object-Oriented Finite Elements  

Science Conference Proceedings (OSTI)

... OOF2 is one program, but can be loaded modularly ... Floating ? Require a field to have a particular profile, allow profile to relax ? Force ...

2013-07-05T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

DOLFIN: Automated finite element computing  

E-Print Network (OSTI)

of examples are presented to demonstrate the use of the library in application code. Categories and Subject Descriptors: G.4 [Mathematical software]: Algorithm Design, Effi- ciency, User Interfaces; G.1.8 [Numerical analysis]: Partial differential equations... backend. DOLFIN relies on a form compiler for generation of the problem-specific code. The form compiler generates code conforming to the UFC (Unified Form-assembly Code) interface, either at compile-time or run- time, and the generated code is called...

Logg, Anders; Wells, G N

2009-02-25T23:59:59.000Z

322

DOLFIN: Automated Finite Element Computing  

E-Print Network (OSTI)

of examples are presented to demonstrate the use of the library in application code. Categories and Subject Descriptors: G.4 [Mathematical software]: Algorithm Design, Effi- ciency, User Interfaces; G.1.8 [Numerical analysis]: Partial differential equations... for generation of the problem-specific code. The form compiler generates code conforming to the UFC (Unified Form-assembly Code) interface, either at compile-time or run-time, and the generated code is called during assembly by DOLFIN. A small interface layer...

Logg, Anders; Wells, G N

2009-01-01T23:59:59.000Z

323

Properties and performance modelling of finite buffer M/G/1/K networks  

Science Conference Proceedings (OSTI)

Finite buffer, single-server queueing systems and networks are difficult to analyze since the length of time a customer spends in the system does not follow the Markovian property. A two-moment approximation schema is developed for the probability distribution ... Keywords: Finite buffers, Queueing networks

J. MacGregor Smith

2011-04-01T23:59:59.000Z

324

A Global Multilevel Atmospheric Model Using a Vector Semi-Lagrangian Finite-Difference Scheme. Part I: Adiabatic Formulation  

Science Conference Proceedings (OSTI)

An adiabatic global multilevel primitive equation model using a two time-level, semi-Lagrangian semi-implicit finite-difference integration scheme is presented. A Lorenz grid is used for the vertical discretization and a C grid for the horizontal ...

J. R. Bates; S. Moorthi; R. W. Higgins

1993-01-01T23:59:59.000Z

325

A Multimoment Finite-Volume Shallow-Water Model on the YinYang Overset Spherical Grid  

Science Conference Proceedings (OSTI)

A numerical model for shallow-water equations has been built and tested on the YinYang overset spherical grid. A high-order multimoment finite-volume method is used for the spatial discretization in which two kinds of so-called moments of the ...

Xingliang Li; Dehui Chen; Xindong Peng; Keiko Takahashi; Feng Xiao

2008-08-01T23:59:59.000Z

326

A Well-balanced Finite Volume-Augmented Lagrangian Method for an Integrated Herschel-Bulkley Model  

Science Conference Proceedings (OSTI)

We are interested in the derivation of an integrated Herschel-Bulkley model for shallow flows, as well as in the design of a numerical algorithm to solve the resulting equations. The goal is to simulate the evolution of thin sheet of viscoplastic materials ... Keywords: Avalanche, Finite volume, Herschel-Bulkley, Variational inequality, Viscous shallow water, Well balanced

C. Acary-Robert; E. D. Fernndez-Nieto; G. Narbona-Reina; P. Vigneaux

2012-12-01T23:59:59.000Z

327

The Battery-Discharge-Model: A Class of Stochastic Finite Automata to Simulate Multidimensional Continued Fraction Expansion  

E-Print Network (OSTI)

We define an infinite stochastic state machine, the Battery-Discharge-Model (BDM), which simulates the behaviour of linear and jump complexity of the continued fraction expansion of multidimensional formal power series, a relevant security measure in the cryptanalysis of stream ciphers. We also obtain finite approximations to the infinite BDM, where polynomially many states suffice to approximate with an exponentially small error the probabilities and averages for linear and jump complexity of M-multisequences of length n over the finite field F_q, for any M, n, q.

Vielhaber, Michael

2007-01-01T23:59:59.000Z

328

Pultrusion manufacturing process development by computational modelling and methods  

Science Conference Proceedings (OSTI)

This paper deals with the modelling and development of computational schemes to simulate pultrusion processes. Two different computational methods, finite differences and elements, are properly developed and critically analyzed. The methods are applied ... Keywords: Degree of cure, Finite difference method, Finite element method, Numerical modelling, Pultrusion, Temperature

P. Carlone; G. S. Palazzo; R. Pasquino

2006-10-01T23:59:59.000Z

329

Rolling Element Bearing Stiffness Matrix Determination (Presentation)  

DOE Green Energy (OSTI)

Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

Guo, Y.; Parker, R.

2014-01-01T23:59:59.000Z

330

Can Finite Size Effects in the Poland-Scheraga Model Explain Simulations of a Simple Model for DNA Denaturation ?  

E-Print Network (OSTI)

We compare results of previous simulations of a simple model of DNA denaturation to the predictions of the Poland-Scheraga model. Concentrating on the critical region of the latter model we calculate both thermodynamic quantities and the distribution functions measured in the simulations. We find that the Poland-Scheraga model yields an excellent fit to the data, provided (i) we include a (singular) factor weighting the open ends of the doubly stranded chain, and (ii) we keep the leading corrections to the finite size scaling limit. The exponent c_1, which governs the end-weighting factor, is fairly well determined: 0.1 <~ c_1 <~ 0.15. The exponent c, which governs the length distribution of large loops, is determined only poorly. The data are compatible with values of c in at least the range 1.9 <~ c <~ 2.2. From the data it therefore cannot be decided whether the denaturation transition asymptotically is of first or of second order. We suggest that simulations of doubly stranded chains closed at both ends might allow for a more precise determination of c.

Lothar Schfer

2005-02-28T23:59:59.000Z

331

Simulation of blasting induced rock motion using spherical element models  

SciTech Connect

Control of the rock motion associated with blasting can have significant economic benefits. For example, surface coal mining can be made more efficient if the overburden material can be cast further with explosives, leaving less work for mechanical equipment. The final muck pile shape in very type of surface and underground blasting is controlled by the blasting induced motion of the rock. A theoretically sound method of predicting rock motion will be beneficial to understanding the blasting process. Discrete element methods have been used for some time to predict rock motion resulting from blasting. What all of these approaches had in common was the use of polygonal elements with corners and sides as well as aspect ratio. Reasonably good results were obtained but treatment of the interactions of the corners and sides of elements was a computationally intensive process that made long simulations with many elements expensive to perform. The use of spherical elements showed increased efficiency but lacked the mechanisms for treating the bulking of the rock mass. The computer program developed was converted from an explicit code to an event-driven code and some bulking mechanisms were added that allowed spherical elements to exert a torque on other spherical elements with which contact was made. The architecture of this program and its event-driven nature made it difficult to vectorize for efficient execution on vector processing machines. A new code called DMC (Distinct Motion Code) has been developed this past year. DMC was designed and written especially to take advantage of super computer vector processing capabilities. This paper will discuss the use of DMC to perform accurate rock motion calculations with very reasonable computation times. 9 refs., 7 figs., 3 tabs.

Taylor, L.M.; Preece, D.S. (Hibbitt, Karlsson and Sorensen, Providence, RI (USA); Sandia National Labs., Albuquerque, NM (USA))

1989-01-01T23:59:59.000Z

332

A Multimoment Constrained Finite-Volume Model for Nonhydrostatic Atmospheric Dynamics  

Science Conference Proceedings (OSTI)

The two-dimensional nonhydrostatic compressible dynamical core for the atmosphere has been developed by using a new nodal-type high-order conservative method, the so-called multimoment constrained finite-volume (MCV) method. Different from the ...

Xingliang Li; Chungang Chen; Xueshun Shen; Feng Xiao

2013-04-01T23:59:59.000Z

333

Dry and Moist Idealized Experiments with a Two-Dimensional Spectral Element Model  

Science Conference Proceedings (OSTI)

A nonhydrostatic, fully compressible spectral element (SE) model is evaluated in a series of two-dimensional idealized simulations. A dry formulation of the model is evaluated for a linear hydrostatic mountain-wave case, and a version with ...

Saa Gaberek; Francis X. Giraldo; James D. Doyle

2012-10-01T23:59:59.000Z

334

Effect of finite chemical potential on QGP-Hadron phase transition in a statistical model of fireball formation  

E-Print Network (OSTI)

We study the effect of finite chemical potential for the QGP constituents in the Ramanathan et al. statistical model (Phys.Rev.C70, 027903,2004). While the earlier computations using this model with vanishing chemical potentials indicated a weakly first order phase transition for the system in the vicinity of 170 MeV (Pramana, 68, 757, 2007), the introduction of finite values for the chemical potentials of the constituents makes the transition a smooth roll over of the phases, while allowing fireball formation with radius of a few "fermi" to take place. This seems to be in conformity with the latest consensus on the nature of the QGP-Hadron phase transition. Keywords: Quark Gluon Plasma, Quark Hadron Phase Transition

R. Ramanathan; Agam k. Jha; K. k. Gupta; S. S. Singh

2008-02-18T23:59:59.000Z

335

Advancements in the behavioral modeling of fuel elements and related structures  

Science Conference Proceedings (OSTI)

An important aspect of the design and analysis of nuclear reactors is the ability to predict the behavior of fuel elements in the adverse environment of a reactor system. By understanding the thermomechanical behavior of the different materials which constitute a nuclear fuel element, analysis and predictions can be made regarding the integrity and reliability of fuel element designs. The SMiRT conference series, through the division on fuel elements and the post-conference seminars on fuel element modeling, provided technical forums for the international participation in the exchange of knowledge concerning the thermomechanical modeling of fuel elements. This paper discusses the technical advances in the behavioral modeling of fuel elements presented at the SMiRT conference series since its inception in 1971. Progress in the areas of material properties and constitutive relationships, modeling methodologies, and integral modeling approaches was reviewed and is summarized in light of their impact on the thermomechanical modeling of nuclear fuel elements. 34 refs., 5 tabs.

Billone, M.C.; Montgomery, R.O.; Rashid, Y.R.; Head, J.L. (Argonne National Lab., IL (USA); ANATECH Research Corp., San Diego, CA (USA); Royal Naval Coll., Greenwich (UK))

1989-01-01T23:59:59.000Z

336

Dual Bosonic Thermal Green Function and Fermion Correlators of the Massive Thirring Model at a Finite Temperature  

E-Print Network (OSTI)

The Euclidian thermal Green function of the two-dimensional (2D) free massless scalar field in coordinate space is written as the real part of a complex analytic function of a variable that conformally maps the infinite strip $-\\inftyGreen function as the imaginary part of that function. Using both the thermal Green function and its dual, we obtain an explicit series expression for the fermionic correlation functions of the massive Thirring model (MTM) at a finite temperature.

Leonardo Mondaini; E. C. Marino

2007-08-07T23:59:59.000Z

337

{pi} and {sigma} mesons at finite temperature and density in the Nambu-Jona-Lasinio model with dimensional regularization  

SciTech Connect

Dynamical symmetry breaking and meson masses are studied in the Nambu-Jona-Lasinio model at finite temperature and chemical potential using dimensional regularization. Since the model is not renormalizable in four space-time dimensions, physical results and parameters depend on the regularization method. Following the imaginary-time formalism, we introduce the temperature T and the chemical potential {mu}. The parameters of the model are fixed by calculating the pion mass and decay constant in dimensional regularization at T={mu}=0.

Inagaki, T.; Kimura, D.; Kvinikhidze, A. [Information Media Center, Hiroshima University, Higashi-Hiroshima (Japan); Department of Physical Science, Hiroshima University, Higashi-Hiroshima (Japan); A. Razmadze Mathematical Institute of Georgian Academy of Sciences, Tbilisi (Georgia)

2008-06-01T23:59:59.000Z

338

Nonlocal Polyakov-Nambu-Jona-Lasinio model with wave function renormalization at finite temperature and chemical potential  

Science Conference Proceedings (OSTI)

We study the phase diagram of strongly interacting matter in the framework of a nonlocal SU(2) chiral quark model which includes wave function renormalization and coupling to the Polyakov loop. Both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations are considered. Special attention is paid to the determination of the critical points, both in the chiral limit and at finite quark mass. In particular, we study the position of the critical end point as well as the value of the associated critical exponents for different model parametrizations.

Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Orsaria, M. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Gravitation, Astrophysics and Cosmology Group, FCAyG, UNLP, La Plata (Argentina); Scoccola, N. N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)

2010-09-01T23:59:59.000Z

339

Vectorized Finite State Automata  

E-Print Network (OSTI)

We present a technique of finite state parsing based on vectorization and describe the application of this technique to a well-known problem of natural language processing, that of extracting relational information from English text. We define Vectorized Finite State Automata, the theoretical model behind the applied system, and discuss their significance.

Andrs Kornai

1996-01-01T23:59:59.000Z

340

Geometrically exact 3D beam element for arbitrary large rigid-elastic deformation analysis of aerospace structures  

Science Conference Proceedings (OSTI)

This paper presents a geometrically exact beam theory and a corresponding displacement-based finite-element formulation for modeling and analysis of highly flexible beam components of multibody systems undergoing huge static/dynamic rigid-elastic deformations. ... Keywords: Flexible multibody systems, Geometrically exact beam theory, Jaumann strains, Nonlinear finite element analysis, Nonlinear structural mechanics

Genyong Wu; Xingsuo He; P. Frank Pai

2011-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

GOMA 6.0 : a full-Newton finite element program for free and moving boundary problems with coupled fluid/solid momentum, energy, mass, and chemical species transport : user%3CU%2B2019%3Es guide.  

SciTech Connect

Goma 6.0 is a finite element program which excels in analyses of multiphysical processes, particularly those involving the major branches of mechanics (viz. fluid/solid mechanics, energy transport and chemical species transport). Goma is based on a full-Newton-coupled algorithm which allows for simultaneous solution of the governing principles, making the code ideally suited for problems involving closely coupled bulk mechanics and interfacial phenomena. Example applications include, but are not limited to, coating and polymer processing flows, super-alloy processing, welding/soldering, electrochemical processes, and solid-network or solution film drying. This document serves as a user's guide and reference.

Schunk, Peter Randall; Rao, Rekha Ranjana; Chen, Ken Shuang; Labreche, Duane A.; Sun, Amy Cha-Tien; Hopkins, Matthew Morgan; Moffat, Harry K.; Roach, Robert Allen; Hopkins, Polly L.; Notz, Patrick K.; Roberts, Scott Alan; Sackinger, Philip A.; Subia, Samuel Ramirez; Wilkes, Edward Dean; Baer, Thomas A.; Noble, David R.; Secor, Robert B. [3M Engineering Systems and Technology, St. Paul, MN

2013-07-01T23:59:59.000Z

342

Conservative one-dimensional finite volume discretization of a new cavitation model for pistonring lubrication  

E-Print Network (OSTI)

achieved in "vacuum systems" used in physics and in the electronics industry are far from being absolutely system elements. The most commonly-used materials are stainless steel, aluminum, and glass. 1

Buscaglia, Gustavo C.

343

Computational upscaled modeling of heterogeneous porous media flow utilizing finite volume method  

E-Print Network (OSTI)

In this dissertation we develop and analyze numerical method to solve general elliptic boundary value problems with many scales. The numerical method presented is intended to capture the small scales e?ect on the large scale solution without resolving the small scale details, which is done through the construction of a multiscale map. The multiscale method is more e?ective when the coarse element size is larger than the small scale length. To guarantee a numerical conservation, a ?nite volume element method is used to construct the global problem. Analysis of the multiscale method is separately done for cases of linear and nonlinear coe?cients. For linear coe?cients, the multiscale ?nite volume element method is viewed as a perturbation of multiscale ?nite element method. The analysis uses substantially the existing ?nite element results and techniques. The multiscale method for nonlinear coe?cients will be analyzed in the ?nite element sense. A class of correctors corresponding to the multiscale method will be discussed. In turn, the analysis will rely on approximation properties of this correctors. Several numerical experiments verifying the theoretical results will be given. Finally we will present several applications of the multiscale method in the ?ow in porous media. Problems that we will consider are multiphase immiscible ?ow, multicomponent miscible ?ow, and soil in?ltration in saturated/unsaturated ?ow.

Ginting, Victor Eralingga

2003-05-01T23:59:59.000Z

344

Fast history matching of finite-difference model, compressible and three-phase flow using streamline-derived sensitivities  

E-Print Network (OSTI)

Reconciling high-resolution geologic models to field production history is still a very time-consuming procedure. Recently streamline-based assisted and automatic history matching techniques, especially production data integration by â??travel-time matching,â? have shown great potential in this regard. But no systematic study was done to examine the merits of travel-time matching compared to more traditional amplitude matching for field-scale application. Besides, most applications were limited to two-phase water-oil flow because current streamline models are limited in their ability to incorporate highly compressible flow in a rigorous and computationally efficient manner. The purpose of this work is fourfold. First, we quantitatively investigated the nonlinearities in the inverse problems related to travel time, generalized travel time, and amplitude matching during production data integration and their impact on the solution and its convergence. Results show that the commonly used amplitude inversion can be orders of magnitude more nonlinear compared to the travel-time inversion. Both the travel-time and generalized travel time inversion (GTTI) are shown to be more robust and exhibit superior convergence characteristics. Second, the streamline-based assisted history matching was enhanced in two important aspects that significantly improve its efficiency and effectiveness. We utilize streamline-derived analytic sensitivities to determine the location and magnitude of the changes to improve the history match, and we use the iterative GTTI for model updating. Our approach leads to significant savings in time and manpower. Third, a novel approach to history matching finite-difference models that combines the efficiency of analytical sensitivity computation of the streamline models with the versatility of finite-difference simulation was developed. Use of finite-difference simulation can account for complex physics. Finally, we developed an approach to history matching three-phase flow using a novel compressible streamline formulation and streamline-derived analytic sensitivities. Streamline models were generalized to account for compressible flow by introducing a relative density of total fluids along streamlines and a density-dependent source term in the saturation equation. The analytical sensitivities are calculated based on the rigorous streamline formulation. The power and utility of our approaches have been demonstrated using both synthetic and field examples.

Cheng, Hao

2005-08-01T23:59:59.000Z

345

Finite rate chemistry and presumed PDF models for premixed turbulent combustion  

SciTech Connect

The sensitivity of the prediction of mean reaction rates in turbulent premixed flames to presumed PDF shape is studied. Three different presumed PDF shapes are considered: (i) a beta function PDF, (ii) a twin delta function PDF, and (iii) a PDF based on unstrained laminar flame properties. The unstrained laminar flame has the same thermochemistry as the turbulent flame. Emphasis is placed on capturing the finite rate chemistry effects and obtaining a simple expression for the mean reaction rate. It is shown that, as the PDFs approach their bimodal limit, the mean reaction rate expressions obtained using the above three PDFs reduce to a common form. These expressions differ only in the numerical value of a multiplying factor. Predictions are compared with DNS data. Under the conditions of this comparison, the beta function and twin delta function PDFs lead to significant errors, while the PDF based on properties of an unstrained laminar flame gives good agreement with the DNS. (author)

Bray, K.N.C.; Swaminathan, N. [Cambridge University, Cambridge (United Kingdom); Champion, M. [Laboratoire de Combustion et de Detonique, UPR9028 CNRS, ENSMA, 86961 Futuroscope (France); Libby, P.A. [University of California, San Diego, La Jolla, CA (United States)

2006-09-15T23:59:59.000Z

346

Well Models for Mimetic Finite Difference Methods and Improved Representation of Wells inMultiscale Methods.  

E-Print Network (OSTI)

??In reservoir simulation, the modeling and the representation of wells are critical factors. The standard approach for well modeling is to couple the well to (more)

Ligaarden, Ingeborg Skjelkvle

2008-01-01T23:59:59.000Z

347

A damage model for rock fragmentation and comparison of calculations with blasting experiments in granite  

SciTech Connect

Early attempts at estimation of stress wave damage due to blasting by use of finite element calculations met with limited success due to numerical instabilities that prevented calculations from being carried to late times. An improved damage model allows finite element calculations which remain stable at late times. Reasonable agreement between crater profiles calculated with this model using the PRONTO finite element program and excavated crater profiles from blasting experiments in granite demonstrate a successful application of this model. Detailed instructions for use of this new damage model with the PRONTO finite element programs are included. 18 refs., 16 figs.

Thorne, B.J.

1990-10-01T23:59:59.000Z

348

Challenges for a reliable shell model description of the neutrinoless double beta decay matrix elements  

SciTech Connect

Assuming that the neutrinos are Majorana particles and the neutrinoless double beta (0{nu}{beta}{beta}) decay is observed, a reliable 0{nu}{beta}{beta} matrix element is necessary to decide the neutrino mass hierarchy and the minimum neutrino mass. Many nuclear structure techniques, including the shell model, are presently used to calculate these matrix elements. In the last few years one could see a slow convergence of these results, but not yet at a level of 20 several shell model effective interactions and varying other parameters, finding results in a range that spans about 20In this contribution we describe challenges for obtaining reliable shell model 0{nu}{beta}{beta} matrix elements, with emphasis to {sup 76}Ge and {sup 82}Se decays.

Horoi, Mihai [Department of Physics, Central Michigan University, Mount Pleasant, Michigan, 48859 (United States)

2011-12-16T23:59:59.000Z

349

voronoi_fe_meshing_rev_2.doc 12:48 10.08.01 1/19 AUTOMATIC FINITE ELEMENT MESHING  

E-Print Network (OSTI)

element method, stress corrosion cracking # Corresponding author. Tel. +49/7247/82 4155 Fax +49 and propagation in creep [6], [7], thermal fatigue [8] and intergranular stress-corrosion [9]. The applications like aggregates of grains in polycrystals, patterns of intergranular cracks and composites. Solution

Cizelj, Leon

350

2+1 Flavor Polyakov--Nambu--Jona-Lasinio Model at Finite Temperature and Nonzero Chemical Potential  

E-Print Network (OSTI)

We extend the Polyakov-loop improved Nambu--Jona-Lasinio (PNJL) model to 2+1 flavor case to study the chiral and deconfinement transitions of strongly interacting matter at finite temperature and nonzero chemical potential. The Polyakov-loop, the chiral susceptibility of light quarks (u and d) and the strange quark number susceptibility as functions of temperature at zero chemical potential are determined and compared with the recent results of Lattice QCD simulations. We find that there is always an inflection point in the curve of strange quark number susceptibility accompanying the appearance of the deconfinement phase, which is consistent with the result of Lattice QCD simulations. Predictions for the case at nonzero chemical potential and finite temperature are made as well. We give the phase diagram in terms of the chemical potential and temperature and find that the critical endpoint (CEP) moves down to low temperature and finally disappears with the decrease of the strength of the 't Hooft flavor-mixing interaction.

Wei-jie Fu; Zhao Zhang; Yu-xin Liu

2007-11-01T23:59:59.000Z

351

Zero-order trace element distribution model for the Great Plains Coal Gasification Plant: Topical report  

SciTech Connect

The Morgantown Energy Technology Center of the US DOE is developing a series for models of environmental systems. Both zero-order and detailed models are being developed. Detailed models are based on fundamental engineering principles and the use of detailed physical and chemical property data; reliance on empirical relationships and correlations is minimized. The key advantage of detailed models is their predictive capabilities and utility in performing valid comparative analyses. An important prerequisite to the development of detailed models in the availability of representative, long-term process and environmental data. These data are needed both to develop the models as well as to validate them. Zero-order models are less rigorous and have less predictive capability than detailed models since they are based on empirical estimates and simple correlations. However, they can be developed relatively quickly and are significantly less expensive to develop and use compared to detailed models. Zero-order models are useful in identifying potential environmental or control technology problems. As such, they can help direct future research and development efforts. They can provide useful information when comprehensive data are unavailable for detailed modeling, and can be used as a screening tool to identify process alternatives which appear to warrant more detailed modeling. This report describes a zero-order trace element distribution model for the Great Plains Coal Gasification Plant located near Beulah, North Dakota. The model estimates how trace elements entering the plant in the feed coal are distributed to the plant's process and waste streams. Elements that may be introduced to the plant's waste streams from sorbents and/or catalysts (e.g., Vanadium in makeup Stretford solution) are not considered in the model. 13 refs.

Thomas, W.C.; Page, G.C.; Magee, R.A.

1987-04-01T23:59:59.000Z

352

Constraints on AGB models from the heavy-element composition of presolar SiC grains  

E-Print Network (OSTI)

Presolar SiC grains formed around Asymptotic Giant Branch (AGB) stars during their carbon-rich phase and contain heavy elements in trace amounts showing the signature of the slow neutron capture process (s process). Thanks to recent advances in analysis techniques, SiC data now provide extremely precise information on neutron capture cross sections and AGB models. For example, high-precision data for Mo in single SiC grains indicate that a revision of the 95Mo neutron capture cross section is needed, while data for Zr indicates that the 22Ne(alpha,n)25Mg reaction cannot be a dominant neutron source for the s process in AGB stars. We present model predictions for the composition of Fe-peak elements in AGB stars. These elements could be analysed in the near future thus providing further stringent constraints to our understanding of AGB stars.

M. Lugaro; A. M. Davis; R. Gallino; M. R. Savina; M. J. Pellin

2004-10-12T23:59:59.000Z

353

Computational modeling and experimental investigation of effects of compositional elements on interface and design aesthetics  

Science Conference Proceedings (OSTI)

This article describes computational modeling and two corresponding experimental investigations of the effects of symmetry, balance and quantity of construction elements on interface aesthetic judgments. In the first experiment, 30 black and white geometric ... Keywords: Aesthetics, Balance, Display evaluation, Engineering aesthetics, Symmetry

Michael Bauerly; Yili Liu

2006-08-01T23:59:59.000Z

354

Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux  

Science Conference Proceedings (OSTI)

We show how a general class of spatio-temporal nonlinear impulse-response forecast networks (Volterra networks) can be constructed from a taxonomy of nonlinear autoregressive integrated moving average with exogenous inputs (NAR-MAX) input-output equations, and used to model the evolution of energetic particle f uxes in the Van Allen radiation belts. We present initial results for the nonlinear response of the radiation belts to conditions a month earlier. The essential features of spatio-temporal observations are recovered with the model echoing the results of state space models and linear f nite impulse-response models whereby the strongest coupling peak occurs in the preceding 1-2 days. It appears that such networks hold promise for the development of accurate and fully data-driven space weather modelling, monitoring and forecast tools.

Taylor, M.; Daglis, I. A.; Anastasiadis, A. [Institute for Space Applications and Remote Sensing(ISARS), National Observatory of Athens (NOA), Metaxa and Vasillis Pavlou Street, Penteli, Athens 15236 (Greece); Vassiliadis, D. [Department of Physics, Hodges Hall, PO Box 6315, West Virginia University, Morgantown, WV 26506-6315 (United States)

2011-01-04T23:59:59.000Z

355

Modeling the compressive deformation of metal micro-textured thermal interface materials using SEM geometry reconstruction  

Science Conference Proceedings (OSTI)

Idealized and simplified geometries are commonly used in finite element models to ease model creation and meshing. However, at smaller length-scales, the influence of geometrical imperfections and defects can significantly affect the accuracy of the ... Keywords: Buckling, Finite element modeling, Metal micro-textured thermal interface materials, Plastic deformation, SEM stereomicroscopy, Surface reconstruction

R. Kempers; P. Ahern; A. J. Robinson; A. M. Lyons

2012-02-01T23:59:59.000Z

356

Intelligent process modeling and optimization of die-sinking electric discharge machining  

Science Conference Proceedings (OSTI)

This paper reports an intelligent approach for process modeling and optimization of electric discharge machining (EDM). Physics based process modeling using finite element method (FEM) has been integrated with the soft computing techniques like artificial ... Keywords: Artificial neural networks (ANN), Electric discharge machining (EDM), Finite element method (FEM), Non-dominated sorting genetic algorithm (NSGA), Process modeling and optimization, Scaled conjugate gradient algorithm (SCG)

S. N. Joshi; S. S. Pande

2011-03-01T23:59:59.000Z

357

Modeling Investment Castings  

Science Conference Proceedings (OSTI)

Once the finite-element meshes of the metal, mold, mold wrap, and furnace are created, they are assembled into a final model as shown in Figure 6. It is then...

358

Solution of Nonlinear Finite Difference Ocean Models by Optimization Methods with Sensitivity and Observational Strategy Analysis  

Science Conference Proceedings (OSTI)

Dynamical models driven by observed forcing fields (e.g., the wind) have a true solution uncertainty owing to observational errors in the driving. This uncertainty is usually hidden from view because conventional numerical methods do not easily ...

Jens Schrter; Carl Wunsch

1986-11-01T23:59:59.000Z

359

Smart finite state devices: A modeling framework for demand response technologies  

E-Print Network (OSTI)

We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the ...

Turitsyn, Konstantin

360

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

due to M7 class offshore earthquakes, Geophysical Researchof the convergent Pacific margin offshore Costa Rica fromin the ODP Leg 170 area offshore Costa Rica, Earth and

LaBonte, Alison L

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

due to M7 class offshore earthquakes, Geophysical Researchof the convergent Pacific margin offshore Costa Rica fromin the ODP Leg 170 area offshore Costa Rica, Earth and

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

362

An Investigation of Deformation and Fluid Flow at Subduction Zones Using Newly Developed Instrumentation and Finite Element Modeling  

E-Print Network (OSTI)

isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,

LaBonte, Alison L

2007-01-01T23:59:59.000Z

363

An investigation of deformation and fluid flow at subduction zones using newly developed instrumentation and finite element modeling  

E-Print Network (OSTI)

isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,isotope studies in the Mojave Desert, California: implications for groundwater chronology and regional seismicity, Chemical Geology,

LaBonte, Alison Louise

2007-01-01T23:59:59.000Z

364

Finite element modeling and experimental study of brittle fracture in tempered martensitic steels for thermonuclear fusion applications.  

E-Print Network (OSTI)

??In this work we have studied brittle fracture in high-chromium reduced activation tempered martensitic steels foreseen as structural materials for thermonuclear fusion reactors. Developing the (more)

Mueller, Pablo Federico

2009-01-01T23:59:59.000Z

365

FINITE ELEMENT STRUCTURAL RESPONSE SENSITIVITY AND RELIABILITY ANALYSES USING SMOOTH VERSUS NON-SMOOTH MATERIAL CONSTITUTIVE MODELS  

E-Print Network (OSTI)

of Engineering Mechanics (ASCE), 13. Conte, J.P. , Barbato,Engineering Mechanics Division (ASCE), 111(EM1):85-104. 15.Engineering Mechanics Division (ASCE), 113(EM8):1208-1225.

Barbato, Michele; Conte, Joel P

2006-01-01T23:59:59.000Z

366

Smart Finite State Devices: A Modeling Framework for Demand Response Technologies  

E-Print Network (OSTI)

We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the following four types: (a) optional loads that can be shed, e.g. light dimming; (b) deferrable loads that can be delayed, e.g. dishwashers; (c) controllable loads with inertia, e.g. thermostatically-controlled loads, whose task is to maintain an auxiliary characteristic (temperature) within pre-defined margins; and (d) storage devices that can alternate between charging and generating. Our analysis of the devices seeks to find their optimal price-taking control strategy under a given stochastic model of the distribution market.

Turitsyn, Konstantin; Ananyev, Maxim; Chertkov, Michael

2011-01-01T23:59:59.000Z

367

Discrete element modeling of rock deformation, fracture network development and permeability evolution under hydraulic stimulation  

SciTech Connect

Key challenges associated with the EGS reservoir development include the ability to reliably predict hydraulic fracturing and the deformation of natural fractures as well as estimating permeability evolution of the fracture network with time. We have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a network flow model. In DEM model, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external and internal load is applied. The natural fractures are represented by a series of connected line segments. Mechanical bonds that intersect with such line segments are removed from the DEM model. A network flow model using conjugate lattice to the DEM network is developed and coupled with the DEM. The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms the mechanical bonds and breaks them if the deformation reaches a prescribed threshold value. Such deformation/fracturing in turn changes the permeability of the flow network, which again changes the evolution of fluid pressure, intimately coupling the two processes. The intimate coupling between fracturing/deformation of fracture networks and fluid flow makes the meso-scale DEM- network flow simulations necessary in order to accurately evaluate the permeability evolution, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed. Methodology for coupling the DEM model with continuum flow and heat transport models will also be discussed.

Shouchun Deng; Robert Podgorney; Hai Huang

2011-02-01T23:59:59.000Z

368

Scalar O(N) Model at Finite Temperature -- 2PI Effective Potential in Different Approximations  

E-Print Network (OSTI)

We calculate the two-particle irreducible (2PI) effective potential of the O(N) linear sigma model in 1+1 dimensions. The approximations we use are the next-to-leading order of a 1/N expansion (for arbitrary N) and a kind of "resummed loop approximation" for N=1. We show that the effective potential of the 1/N expansion is convex for N=4 and N=10 whereas it is not for the "loop" expansion and the case N=1 of the 1/N expansion.

Jurgen Baacke; Stefan Michalski

2004-09-14T23:59:59.000Z

369

Verification and benchmarking of MAGNUM-2D: a finite element computer code for flow and heat transfer in fractured porous media  

SciTech Connect

The objective of this work is to assess prediction capabilities and features of the MAGNUM-2D computer code in relation to its intended use in the Basalt Waste Isolation Project (BWIP). This objective is accomplished through a code verification and benchmarking task. Results are documented which support correctness of prediction capabilities in areas of intended model application. 10 references, 43 figures, 11 tables.

Eyler, L.L.; Budden, M.J.

1985-03-01T23:59:59.000Z

370

Constraining deflagration models of Type Ia supernovae through intermediate-mass elements  

E-Print Network (OSTI)

The physical structure of a nuclear flame is a basic ingredient of the theory of Type Ia supernovae (SNIa). Assuming an exponential density reduction with several characteristic times we have followed the evolution of a planar nuclear flame in an expanding background from an initial density 6.6 10^7 g/cm3 down to 2 10^6 g/cm3. The total amount of synthesized intermediate-mass elements (IME), from silicon to calcium, was monitored during the calculation. We have made use of the computed mass fractions, X_IME, of these elements to give an estimation of the total amount of IME synthesized during the deflagration of a massive white dwarf. Using X_IME and adopting the usual hypothesis that turbulence decouples the effective burning velocity from the laminar flame speed, so that the relevant flame speed is actually the turbulent speed on the integral length-scale, we have built a simple geometrical approach to model the region where IME are thought to be produced. It turns out that a healthy production of IME involves the combination of not too short expansion times, t_c > 0.2 s, and high turbulent intensities. According to our results it could be difficult to produce much more than 0.2 solar masses of intermediate-mass elements within the deflagrative paradigma. The calculations also suggest that the mass of IME scales with the mass of Fe-peak elements, making it difficult to conciliate energetic explosions with low ejected nickel masses, as in the well observed SN1991bg or in SN1998de. Thus a large production of Si-peak elements, especially in combination with a low or a moderate production of iron, could be better addressed by either the delayed detonation route in standard Chandrasekhar-mass models or, perhaps, by the off-center helium detonation in the sub Chandrasekhar-mass scenario.

D. Garcia-Senz; E. Bravo; R. M. Cabezon; S. E. Woosley

2006-09-15T23:59:59.000Z

371

Elemental Solubility Tendency for the Phases of Uranium by Classical Models Used to Predict Alloy Behavior  

Science Conference Proceedings (OSTI)

Traditional alloy theory models, specifically Darken-Gurry and Miedemas analyses, that characterize solutes in solid solvents relative to physical properties of the elements have been used to assist in predicting alloy behavior. These models will be applied relative to the three solid phases of uranium: alpha (orthorhombic), beta (tetragonal), and gamma (bcc). These phases have different solubilities for specific alloy additions as a function of temperature. The Darken-Gurry and Miedema models, with modifications based on concepts of Waber, Gschneider, and Brewer will be used to predict the behavior of four types of solutes: 1) Transition metals that are used for various purposes associated with the containment as alloy additions in the uranium fuel 2) Transuranic elements in the uranium 3) Rare earth fission products (lanthanides) 4) Transition metals and other fission products Using these solute map criteria, elemental behavior will be predicted as highly soluble, marginally soluble, or immiscible (compound formers) and will be used to compare solute effects during uranium phase transformations. The overlapping of these solute maps are convenient first approximation tools for predicting alloy behavior.

Van Blackwood; Travis Koenig; Saleem Drera; Brajenda Mishra; Davis Olson; Doug Porter; Robert Mariani

2012-03-01T23:59:59.000Z

372

Boundary Conditions of the Hydro-Cascade Model and Relativistic Kinetic Equations for Finite Domains  

E-Print Network (OSTI)

A detailed analysis of the coupled relativistic kinetic equations for two domains separated by a hypersurface having both space- and time-like parts is presented. Integrating the derived set of transport equations, we obtain the correct system of the hydro+cascade equations to model the relativistic nuclear collision process. Remarkably, the conservation laws on the boundary between domains conserve separately both the incoming and outgoing components of energy, momentum and baryonic charge. Thus, the relativistic kinetic theory generates twice the number of conservation laws compared to traditional hydrodynamics. Our analysis shows that these boundary conditions between domains, the three flux discontinuity, can be satisfied only by a special superposition of two cut-off distribution functions for the ``out'' domain. All these results are applied to the case of the phase transition between quark gluon plasma and hadronic matter. The possible consequences for an improved hydro+cascade description of the relativistic nuclear collisions are discussed. The unique properties of the three flux discontinuity and their effect on the space-time evolution of the transverse expansion are also analyzed. The possible modifications of both transversal radii from pion correlations generated by a correct hydro+cascade approach are discussed.

K. A. Bugaev

2004-01-29T23:59:59.000Z

373

First-order finite-Larmor-radius fluid modeling of tearing and relaxation in a plasma pinch  

Science Conference Proceedings (OSTI)

Drift and Hall effects on magnetic tearing, island evolution, and relaxation in pinch configurations are investigated using a non-reduced first-order finite-Larmor-radius (FLR) fluid model with the nonideal magnetohydrodynamics (MHD) with rotation, open discussion (NIMROD) code [C.R. Sovinec and J. R. King, J. Comput. Phys. 229, 5803 (2010)]. An unexpected result with a uniform pressure profile is a drift effect that reduces the growth rate when the ion sound gyroradius ({rho}{sub s}) is smaller than the tearing-layer width. This drift is present only with warm-ion FLR modeling, and analytics show that it arises from {nabla}B and poloidal curvature represented in the Braginskii gyroviscous stress. Nonlinear single-helicity computations with experimentally relevant {rho}{sub s} values show that the warm-ion gyroviscous effects reduce saturated-island widths. Computations with multiple nonlinearly interacting tearing fluctuations find that m = 1 core-resonant-fluctuation amplitudes are reduced by a factor of two relative to single-fluid modeling by the warm-ion effects. These reduced core-resonant-fluctuation amplitudes compare favorably to edge coil measurements in the Madison Symmetric Torus (MST) reversed-field pinch [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. The computations demonstrate that fluctuations induce both MHD- and Hall-dynamo emfs during relaxation events. The presence of a Hall-dynamo emf implies a fluctuation-induced Maxwell stress, and the simulation results show net transport of parallel momentum. The computed magnitude of force densities from the Maxwell and competing Reynolds stresses, and changes in the parallel flow profile, are qualitatively and semi-quantitatively similar to measurements during relaxation in MST.

King, J. R. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States); Tech-X Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303 (United States); Sovinec, C. R. [Department of Engineering-Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Mirnov, V. V. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States)

2012-05-15T23:59:59.000Z

374

Numerical modeling of electrochemical-mechanical interactions in lithium polymer batteries  

Science Conference Proceedings (OSTI)

This paper presents a multi-scale finite element approach for lithium batteries to study electrochemical-mechanical interaction phenomena at macro- and micro-scales. The battery model consists of a lithium foil anode, a separator, and a porous cathode ... Keywords: Finite element method, Homogenization, Multi-scale modeling, Porous electrode theory

Stephanie Golmon; Kurt Maute; Martin L. Dunn

2009-12-01T23:59:59.000Z

375

Development of a numerical computer code and circuit element models for simulation of firing systems  

SciTech Connect

Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interactive editor and a batch driver have been written to ease the use of the SPICE program by system designers, and the interactive graphical post processor, NUTMEG, supplied by U. C. Berkeley with SPICE version 3B1, has been interfaced to the output from the modified SPICE. Documentation and installation aids have been provided to make the total software system accessible to PC users. Sample problems show that the resulting code is in agreement with the FIRESET code on which the fuse model was based (with some modifications to the dynamics of scaling fuse parameters). In order to allow for more complex simulations of firing systems, studies have been made of additional special circuit elements--switches and ferrite cored inductances. A simple switch model has been investigated which promises to give at least a first approximation to the physical effects of a non ideal switch, and which can be added to the existing SPICE circuits without changing the SPICE code itself. The effect of fast rise time pulses on ferrites has been studied experimentally in order to provide a base for future modeling and incorporation of the dynamic effects of changes in core magnetization into the SPICE code. This report contains detailed accounts of the work on these topics performed during the period it covers, and has appendices listing all source code written documentation produced.

Carpenter, K.H. (Kansas State Univ., Manhattan, KS (USA). Dept. of Electrical and Computer Engineering)

1990-07-02T23:59:59.000Z

376

Research on Regional Differences of Urban Resident Consumption Structure in China Based on Fuzzy Matter Element Model  

Science Conference Proceedings (OSTI)

Study of residents consumption structure plays an important role in macroeconomic policy formulation. Based on per capita annual consumption expenditure of urban households, the fuzzy matter element model is used to evaluate urban resident consumption ... Keywords: comsumption structure, fuzzy matter-element, Euclid approach degree, government consumption expenditure

Hong Li; Bo Zhou

2010-11-01T23:59:59.000Z

377

Gurson's Model: ALE Formulation and Strain Localization  

Science Conference Proceedings (OSTI)

This paper presents a brief review of Gurson's damage model, employed to describes the strength degradation in ductile metals submitted to large plastic deformations. The damage model is applied using finite elements and an Arbitrary Lagrangian-Eulerian formulation (ALE), to ensure a better quality to the finite elements mesh. The study of the combined application of ALE and Gurson approach to damage modeling and strain localization is the object of this paper.

Cunda, Luiz A. B. da [Departamento de Materiais e Construcao, Fundacao Universidade Federal do Rio Grande, Av. Italia, km 8, Campus Carreiros, 96201-900, Rio Grande, RS (Brazil); Creus, Guillermo J. [Centro de Mecanica Aplicada e Computacional, Universidade Federal do Rio Grande do Sul, Av. Osvaldo Aranha, 99, 3o andar, 90035-190, Porto Alegre, RS (Brazil)

2007-05-17T23:59:59.000Z

378

A Design Procedure for Sonotrodes Based on Dynamic Finite ...  

Science Conference Proceedings (OSTI)

... Based on Dynamic Finite Elements and Laser Triangulation Measurements ... experience acquired on the field about the behaviour of ultrasonic systems in...

379

Neutron Diffraction And Finite Element Simulations.  

Science Conference Proceedings (OSTI)

For example, this was done by Bucezek at al. [18] on a cylinder made of brass. As the materials are different, their results cannot be applied for the present study,...

380

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... and Engineering Laboratory National Institute of ... node arguments. /output/energy. /graphics: /graphics ... stress/elementgroup. /output/stress/statistics: ...

2013-08-23T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... (This menu is called ``tee'' because it acts like the Unix tee command, which is used to save a copy of data in a pipe.) Menus, Functions, Variables. ...

2013-08-23T23:59:59.000Z

382

Using Finite Element Analysis in Failure Analysis  

Science Conference Proceedings (OSTI)

Symposium, Charles R. Morin Memorial Symposium on Failure Analysis and ... Tools for Failure Event Database Management and Probability Risk Analysis for...

383

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... with the word ``OOF'' prominently in the upper left hand corner. ... nx and ny of about 20 are about right if you ... Use the mouse or the tab key to set more ...

2013-07-05T23:59:59.000Z

384

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

NIST Home Page. ... The image may be a scanned micrograph of a composite material, a satellite image of the earth, the result of a computer ...

2013-08-23T23:59:59.000Z

385

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... oriented with a globe, with the origin at the center of the earth and -axis ... Contents /* Send mail to the OOF Team *//* Go to the OOF Home Page */. ...

2013-08-23T23:59:59.000Z

386

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... next up previous contents Next: Function Windows Up: Overview of the Graphical Previous: Menus Contents The Message Window. ...

2013-07-05T23:59:59.000Z

387

OOF: Finite Element Analysis of Microstructures  

Science Conference Proceedings (OSTI)

... This button opens another identical Function Window with identical arguments. Having two function windows allows you to repeatedly execute ...

2013-07-05T23:59:59.000Z

388

Surface kinetic model for isotopic and trace element fractionation during precipitation of calcite from aqueous solution  

SciTech Connect

A surface reaction kinetic model is developed for predicting Ca isotope fractionation and metal/Ca ratios of calcite as a function of rate of precipitation from aqueous solution. The model is based on the requirements for dynamic equilibrium; i.e. proximity to equilibrium conditions is determined by the ratio of the net precipitation rate (R{sub p}) to the gross forward precipitation rate (R{sub f}), for conditions where ionic transport to the growing crystal surface is not rate-limiting. The value of R{sub p} has been experimentally measured under varying conditions, but the magnitude of R{sub f} is not generally known, and may depend on several factors. It is posited that, for systems with no trace constituents that alter the surface chemistry, R{sub f} can be estimated from the bulk far-from-equilibrium dissolution rate of calcite (R{sub b} or k{sub b}), since at equilibrium R{sub f} = R{sub b}, and R{sub p} = 0. Hence it can be inferred that R{sub f} {approx} R{sub p} + R{sub b}. The dissolution rate of pure calcite is measureable and is known to be a function of temperature and pH. At given temperature and pH, equilibrium precipitation is approached when R{sub p} (= R{sub f} - R{sub b}) << R{sub b}. For precipitation rates high enough that R{sub p} >> R{sub b}, both isotopic and trace element partitioning are controlled by the kinetics of ion attachment to the mineral surface, which tend to favor more rapid incorporation of the light isotopes of Ca and discriminate weakly between trace metals and Ca. With varying precipitation rate, a transition region between equilibrium and kinetic control occurs near R{sub p} {approx} R{sub b} for Ca isotopic fractionation. According to this model, Ca isotopic data can be used to estimate R{sub f} for calcite precipitation. Mechanistic models for calcite precipitation indicate that the molecular exchange rate is not constant at constant T and pH, but rather is dependent also on solution saturation state and hence R{sub p}. Allowing R{sub b} to vary as R{sub p}{sup 1/2}, consistent with available precipitation rate studies, produces a better fit to some trace element and isotopic data than a model where R{sub b} is constant. This model can account for most of the experimental data in the literature on the dependence of {sup 44}Ca/{sup 40}Ca and metal/Ca fractionation in calcite as a function of precipitation rate and temperature, and also accounts for {sup 18}O/{sup 16}O variations with some assumptions. The apparent temperature dependence of Ca isotope fractionation in calcite may stem from the dependence of R{sub b} on temperature; there should be analogous pH dependence at pH < 6. The proposed model may be valuable for predicting the behavior of isotopic and trace element fractionation for a range of elements of interest in low-temperature aqueous geochemistry. The theory presented is based on measureable thermo-kinetic parameters in contrast to models that equire hyper-fast diffusivity in near-surface layers of the solid.

DePaolo, D.

2010-10-15T23:59:59.000Z

389

Languages recognized by nondeterministic quantum finite automata  

Science Conference Proceedings (OSTI)

The nondeterministic quantum finite automaton (NQFA) is the only known case wherea one-way quantum finite automaton (QFA) model has been shown to be strictly superiorin terms of language recognition power to its probabilistic counterpart. We give acharacterization ... Keywords: nondeterministic quantum finite automata, one-sided unbounded error, probabilistic automata, sublogarithmic space complexity, two-sided unbounded error

Abuzer Yakaryilmaz; A. C. Cem Say

2010-09-01T23:59:59.000Z

390

Atoms with nuclei of finite extension at finite temperature: A Thomas-Fermi approximation  

Science Conference Proceedings (OSTI)

Atoms at finite temperature and with a nucleus of finite extension are analyzed by a modification of the Thomas-Fermi model for {ital T}{ne}0. Applications to strange-matter atoms are included.

Epele, L.N.; Fanchiotti, H.; Garcriaaa Canal, C.A.; Guillen, J.C. (Laboratorio de Fisica Teorica, Departamento de Fisica, Universidad Nacional de La Plata, Casilla de Correo 67, 1900 La Plata (Argentina))

1990-08-01T23:59:59.000Z

391

Essential elements of modeling gas generation from well defined plutonium materials  

DOE Green Energy (OSTI)

Processing of excess plutonium oxide (and related) materials intended for long-term storage is addressed in DOE standard 3013-2000. The essential elements addressed by this standard are eliminating or reducing to an acceptable level the entities that lead to gas evolution and consequent pressurization of the intended storage container system. Based upon the need to adequately understand and quantify these relevant parameters we briefly describe the current scientific knowledge of gas evolution from such systems. These associated research efforts have included fundamental kinetic and thermodynamic studies of water interactions at actinide oxide surfaces, radiolytic reactions of adsorbed water, interfacial reactions of hydrogen and oxygen, and radiolytic helium production. Utilizing, where possible, experimental parameters for many of the aforementioned processes we have developed a mathematical model with a minimum number of essential components that successfully models gas generation from well-defined PuO{sub 2} materials with known amounts of deliberately added water. In this work we verify this model against real pressure versus time data (described at greater length in another manuscript in these conference proceedings) and subsequently assure the safety envelope of design criteria for both short- and long-term storage and transportation of these material classes. These modeling results predict pressures and gas phase mole fractions over well-defined DOE 3013 container test cases well in advance of actual long-term surveillance information and provide confidence in safe storage of plutonium oxide material classes.

Paffett, M. T. (Mark T.); Kelly, D. (Daniel)

2002-01-01T23:59:59.000Z

392

Constraining deflagration models of Type Ia supernovae through intermediate-mass elements  

E-Print Network (OSTI)

The physical structure of a nuclear flame is a basic ingredient of the theory of Type Ia supernovae (SNIa). Assuming an exponential density reduction with several characteristic times we have followed the evolution of a planar nuclear flame in an expanding background from an initial density 6.6 10^7 g/cm3 down to 2 10^6 g/cm3. The total amount of synthesized intermediate-mass elements (IME), from silicon to calcium, was monitored during the calculation. We have made use of the computed mass fractions, X_IME, of these elements to give an estimation of the total amount of IME synthesized during the deflagration of a massive white dwarf. Using X_IME and adopting the usual hypothesis that turbulence decouples the effective burning velocity from the laminar flame speed, so that the relevant flame speed is actually the turbulent speed on the integral length-scale, we have built a simple geometrical approach to model the region where IME are thought to be produced. It turns out that a healthy production of IME invol...

Garca-Senz, D; Cabezon, R M; Woosley, S E

2006-01-01T23:59:59.000Z

393

An efficient FE model based on combined theory for the analysis of soft core sandwich plate  

Science Conference Proceedings (OSTI)

An efficient C0 continuous finite element (FE) model is developed based on combined theory (refine higher order shear deformation theory (RHSDT) and least square error (LSE) method) for the static analysis of soft core sandwich plate. In this ... Keywords: Composites, Finite element, Laminate, Plates, Sandwich materials

Ravi Prakash Khandelwal; Anupam Chakrabarti; Pradeep Bhargava

2013-05-01T23:59:59.000Z

394

Modeling the effects of shear conversion on low grazing angle bottom penetration.  

Science Conference Proceedings (OSTI)

Modeling shear conversion with finite?element/finite?difference codes at a kilohertz and above is difficult due to the number of computational elements needed for such small wavelengths. Typically six to ten nodes per wavelength are required to attain good accuracy. Thus

Stanley A. Chin?Bing; Joseph E. Murphy

1996-01-01T23:59:59.000Z

395

Surety of human elements of high consequence systems: An organic model  

Science Conference Proceedings (OSTI)

Despite extensive safety analysis and application of safety measures, there is a frequent lament, ``Why do we continue to have accidents?'' Two breakdowns are prevalent in risk management and prevention. First, accidents result from human actions that engineers, analysts and management never envisioned and second, controls, intended to preclude/mitigate accident sequences, prove inadequate. This paper addresses the first breakdown, the inability to anticipate scenarios involving human action/inaction. The failure of controls has been addressed in a previous publication (Forsythe and Grose, 1998). Specifically, this paper presents an approach referred to as surety. The objective of this approach is to provide high levels of assurance in situations where potential system failure paths cannot be fully characterized. With regard to human elements of complex systems, traditional approaches to human reliability are not sufficient to attain surety. Consequently, an Organic Model has been developed to account for the organic properties exhibited by engineered systems that result from human involvement in those systems.

FORSYTHE,JAMES C.; WENNER,CAREN A.

2000-04-25T23:59:59.000Z

396

Integrating complementarity into the 2D displacement discontinuity boundary element method to model faults and fractures with frictional contact properties  

Science Conference Proceedings (OSTI)

We present a two-dimensional displacement discontinuity method (DDM) in combination with a complementarity solver to simulate quasi-static slip on cracks as models for faults and fractures in an otherwise homogeneous, isotropic, linear elastic material. ... Keywords: Boundary element model, Complementarity, Friction, Frictional strength

Elizabeth Ritz; Ovunc Mutlu; David D. Pollard

2012-08-01T23:59:59.000Z

397

ELEMENT MODELING OF INTERNAL STRESS FACTORS FOR ZrB2 SiC  

E-Print Network (OSTI)

The Introduction and Background sections provide information about the thesis topic and summarize the manuscripts. Pages 48 to 66 of this thesis have been prepared in the style used for publication in the 32nd International Conference & Exposition on Advanced Ceramics & Composites Proceedings. The manuscript titled FINITE

Michael Phillip Teague; Dr. William; G. Fahrenholtz

2008-01-01T23:59:59.000Z

398

Neutron scattering from elemental indium, the optical model, and the bound-state potential  

Science Conference Proceedings (OSTI)

Neutron differential elastic-scattering cross sections of elemental indium are measured from 4.5 to 10 MeV at incident-energy intervals of {approx}500 keV. Seventy or more differential values are obtained at each incident energy, distributed between {approx}18{degree} and 160{degree}. These experimental results are combined with lower-energy values previously obtained at this laboratory, and with 11 and 14 MeV results in the literature, to form a comprehensive elastic-scattering database extending from {approx}1.5 to 14 MeV. These data are interpreted in terms of a conventional spherical optical model. The resulting potential is extrapolated to the bound-state regime. It is shown that in the middle of the 50--82 neutron shell, the potential derived from the scattering results adequately describes the binding energies of article states, but does not do well for hole states. The latter shortcoming is attributed to the holes states having occupational probabilities sufficiently different from unity, so that the exclusion principle become a factor, and to the rearrangement of the neutron core. 68 refs.

Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)); Guenther, P.T.; Lawson, R.D.; Smith, A.B. (Argonne National Lab., IL (USA))

1990-06-01T23:59:59.000Z

399

Meshless modeling of deformable shapes and their motion  

Science Conference Proceedings (OSTI)

We present a new framework for interactive shape deformation modeling and key frame interpolation based on a meshless finite element formulation. Starting from a coarse nodal sampling of an object's volume, we formulate rigidity and volume preservation ...

Bart Adams; Maks Ovsjanikov; Michael Wand; Hans-Peter Seidel; Leonidas J. Guibas

2008-07-01T23:59:59.000Z

400

Three-Dimensional Model Simulations of Tides and Buoyancy Currents along the West Coast of Vancouver Island  

Science Conference Proceedings (OSTI)

A three-dimensional finite element model is used to calculate the barotropic tides and seasonal buoyancy flows off the western and northern coasts of Vancouver Island. The model buoyancy currents and the harmonics of eight tidal constituents are ...

Michael G. G. Foreman; Richard E. Thomson

1997-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

A Scalable Spectral Element Eulerian Atmospheric Model (SEE-AM) for NWP: Dynamical Core Tests  

Science Conference Proceedings (OSTI)

A new dynamical core for numerical weather prediction (NWP) based on the spectral element method is presented. This paper represents a departure from previously published work on solving the atmospheric primitive equations in that the horizontal ...

Francis X. Giraldo; Thomas E. Rosmond

2004-01-01T23:59:59.000Z

402

The Adaptive Spectral Element Method and Comparisons with More Traditional Formulations for Ocean Modeling  

Science Conference Proceedings (OSTI)

Triangular spectral elements offer high accuracy in complex geometries, but solving the related matrix problem can be cumbersome and time consuming. In restricted applications, recent developments have led to a family of discontinuous Galerkin ...

Frdric Dupont; Charles A. Lin

2004-01-01T23:59:59.000Z

403

It's Elemental - The Element Fermium  

NLE Websites -- All DOE Office Websites (Extended Search)

Einsteinium Previous Element (Einsteinium) The Periodic Table of Elements Next Element (Mendelevium) Mendelevium The Element Fermium Click for Isotope Data 100 Fm Fermium 257...

404

It's Elemental - The Element Neptunium  

NLE Websites -- All DOE Office Websites (Extended Search)

Uranium Previous Element (Uranium) The Periodic Table of Elements Next Element (Plutonium) Plutonium The Element Neptunium Click for Isotope Data 93 Np Neptunium 237 Atomic...

405

It's Elemental - The Element Ruthenium  

NLE Websites -- All DOE Office Websites (Extended Search)

Technetium Previous Element (Technetium) The Periodic Table of Elements Next Element (Rhodium) Rhodium The Element Ruthenium Click for Isotope Data 44 Ru Ruthenium 101.07 Atomic...

406

It's Elemental - The Element Actinium  

NLE Websites -- All DOE Office Websites (Extended Search)

Radium Previous Element (Radium) The Periodic Table of Elements Next Element (Thorium) Thorium The Element Actinium Click for Isotope Data 89 Ac Actinium 227 Atomic Number: 89...

407

A new time-dependent analytic model for radiation-induced photocurrent in finite 1D epitaxial diodes.  

SciTech Connect

Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, many photocurrent compact models have suffered from accuracy issues due to the use of qualitative approximation, rather than mathematically correct solutions to the ambipolar diffusion equation. A practical consequence of this inaccuracy is that a given model calibration is trustworthy over only a narrow range of operating conditions. This report describes work to produce improved compact models for photocurrent. Specifically, an analytic model is developed for epitaxial diode structures that have a highly doped subcollector. The analytic model is compared with both numerical TCAD calculations, as well as the compact model described in reference [2]. The new analytic model compares well against TCAD over a wide range of operating conditions, and is shown to be superior to the compact model from reference [2].

Verley, Jason C.; Axness, Carl L.; Hembree, Charles Edward; Keiter, Eric Richard; Kerr, Bert (New Mexico Institute of Mining and Technology, Socorro, NM)

2012-04-01T23:59:59.000Z

408

Accumulation of Biomass and Mineral Elements with Calendar Time by Corn: Application of the Expanded Growth Model  

E-Print Network (OSTI)

The expanded growth model is developed to describe accumulation of plant biomass (Mg ha 21) and mineral elements (kg ha 21) in with calendar time (wk). Accumulation of plant biomass with calendar time occurs as a result of photosynthesis for green land-based plants. A corresponding accumulation of mineral elements such as nitrogen, phosphorus, and potassium occurs from the soil through plant roots. In this analysis, the expanded growth model is tested against high quality, published data on corn (Zea mays L.) growth. Data from a field study in South Carolina was used to evaluate the application of the model, where the planting time of April 2 in the field study maximized the capture of solar energy for biomass production. The growth model predicts a simple linear relationship between biomass yield and the growth quantifier, which is confirmed with the data. The growth quantifier incorporates the unit processes of distribution of solar energy which drives biomass accumulation by photosynthesis, partitioning of biomass between light-gathering and structural components of the plants, and an aging function. A hyperbolic relationship between plant nutrient uptake and biomass yield is assumed, and is confirmed for the mineral elements nitrogen (N), phosphorus (P), and potassium (K). It is concluded that the rate limiting process in the system is biomass accumulation by photosynthesis and that nutrient accumulation occurs in virtual equilibrium with biomass accumulation.

Allen R. Overman; Richard V. Scholtz Iii

2011-01-01T23:59:59.000Z

409

Higgs boson resonance parameters and the finite temperature phase transition in a chirally invariant Higgs-Yukawa model  

E-Print Network (OSTI)

We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.

John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy

2011-11-11T23:59:59.000Z

410

Fourth- and Fifth-Order Finite-Difference Methods Applied to a Control-Volume Ocean Model  

Science Conference Proceedings (OSTI)

A semi-implicit, control-volume, nonhydrostatic model is presented. Advection is fifth order with respect to space. Boundary conditions and molecular fluxes are also formulated at fourth order with respect to space. Computational cost is strictly ...

Brian Sanderson; Gary Brassington

2002-09-01T23:59:59.000Z

411

Efficient adaptive meshing of parametric models  

Science Conference Proceedings (OSTI)

Parametric modeling is becoming the representation of choice for most modern solid modelers. However, when generating the finite-element mesh of the model for simulation and analysis, most meshing tools ignore the parametric information and use only ... Keywords: adaptivity, mesh generation, parametric models

Alla Sheffer; Alper ngr

2001-05-01T23:59:59.000Z

412

Nonconforming cell boundary element methods for elliptic problems on triangular mesh  

Science Conference Proceedings (OSTI)

The nonconforming cell boundary element (CBE) methods are proposed. The methods are designed in such a way that they enjoy the mass conservation at the element level and the normal component of fluxes at inter-element boundaries are continuous for unstructured ... Keywords: Multiscale method, 65N12, 65N30, Cell boundary element method, Finite volume, Flux conservation, Mixed finite element, Nonconforming finite element

Youngmok Jeon; Eun-Jae Park

2008-06-01T23:59:59.000Z

413

Finite Heat conduction in 2D Lattices  

E-Print Network (OSTI)

This paper gives a 2D hamonic lattices model with missing bond defects, when the capacity ratio of defects is enough large, the temperature gradient can be formed and the finite heat conduction is found in the model. The defects in the 2D harmonic lattices impede the energy carriers free propagation, by another words, the mean free paths of the energy carrier are relatively short. The microscopic dynamics leads to the finite conduction in the model.

Lei Yang; Yang Kongqing

2001-07-30T23:59:59.000Z

414

Finite - difference modeling of the Yucca Mountain, Nevada Area: a study of the regional water table gradients based on hydraulic conductivity contrasts  

E-Print Network (OSTI)

The Nevada Yucca Mountain site is being investigated to determine if it is a suitable site for the construction of a high-level nuclear waste repository. A feature of concern north of the selected site is an abrupt rise in the water table. This high gradient of 0.15 is flanked to the north by a moderate gradient of 0.015 and to the south by a very small gradient of 0.0001. Since the mechanisms creating this feature have the potential to cause changes in the position and configuration of the water table, they must be understood so risk analysis of the site may be performed. The three distinct gradient regions found at the site may be related to the Cenozoic volcanics, the Paleozoic clastic aquitard, and the Paleozoic carbonates. The large hydraulic gradient regionally corresponds with the northern limit of the Paleozoic carbonates, at the contact of the Eleana Formation, a Paleozoic aquitard. This study investigates, using finite difference modeling, the relationship between the steep hydraulic gradient and hydraulic conductivity contrasts. The site was modeled with flow boundaries to investigate the effects of variable gradient input to the flow balance calculation. A model was run with differential volcanic hydraulic conductivity zones with regulated flow into the carbonates. Constant head boundaries were implemented in models to investigate the effect of both a confined and open carbonate zone and with vertical barriers above the argillite/carbonate contact. The results of the study found that vertical and horizontal hydraulic conductivity contrasts do not fully account for the steep gradients, although the vertical contrasts marginally increase the gradient from horizontal contrasts. The confined carbonate zone model produced results that do not correlate with field data. The vertical barrier model did successfully reproduce steep gradients with gradient steepness related to flow restriction. Through the use of flow boundaries the steep gradient was reproduced successfully with a contrast of 0.8 orders of magnitude by allowing flow into the carbonate zone.

Davidson, Timothy Ross

1994-01-01T23:59:59.000Z

415

Two-Layer Model of Summer Circulation on the Southeast U.S. Continental Shelf  

Science Conference Proceedings (OSTI)

The summer circulation in the South Atlantic Bight is investigated using a two-layer finite element model. Simulations using a steady state mean summer wind field lead to the following conclusions. (i) the adjustment time of the shelf circulation ...

Joao A. Lorenzzetti; John D. Wang; Thomas N. Lee

1988-04-01T23:59:59.000Z

416

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

E-Print Network (OSTI)

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 ...

Meier, Joseph D. (Joseph David)

2013-01-01T23:59:59.000Z

417

Efficient Numerical Methods for an Anisotropic, Nonisothermal, Two-Phase Transport Model of Proton Exchange Membrane Fuel Cell  

Science Conference Proceedings (OSTI)

We carry out model and numerical studies for a three-dimensional, anisotropic, nonisothermal, two-phase steady state transport model of proton exchange membrane fuel cell (PEMFC) in this paper. Besides fully addressing the conservation equations of mass, ... Keywords: Anisotropy, Combined finite element-upwind finite volume, Kirchhoff transformation, Newton's linearization, Nonisothermality, Proton exchange membrane fuel cell (PEMFC), Two-phase transport

Pengtao Sun

2012-04-01T23:59:59.000Z

418

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

SciTech Connect

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.

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

2012-07-01T23:59:59.000Z

419

Choose inter-element coupling to preserve self-adjoint dynamics in multiscale modelling and computation  

Science Conference Proceedings (OSTI)

Consider the macroscale modelling of microscale spatio-temporal dynamics. Here we develop an approach to ensure coarse scale discrete models preserve important self-adjoint properties of the microscale dynamics. The first part explores the discrete modelling ... Keywords: Centre manifold theory, Closure, Macroscale discretisation, Multiscale modelling

A. J. Roberts

2010-10-01T23:59:59.000Z

420

A study of discrete and continuum joint modeling techniques  

SciTech Connect

This paper presents the results of a numerical and experimental study in which finite element and discrete element techniques were used to analyze a layered polycarbonate plate model subjected to uniaxial compression. Also, the two analysis techniques were used to compute the response of an eight meter diameter drift in jointed-rock. The drift was subjected to in-situ and far-field induced thermal stresses. The finite element analyses used a continuum rock model to represent the jointed-rock. A comparison of the analyses showed that the finite element continuum joint model consistently predicted less joint slippage than did the discrete element analyses, although far-field displacements compared well.

Jung, J.; Brown, S.R.

1992-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Improving Battery Design with Electro-Thermal Modeling  

DOE Green Energy (OSTI)

Temperature greatly affects the performance and life of batteries in electric and hybrid vehicles under real driving conditions, so increased attention is being paid to battery thermal management. Sophisticated electrochemical models and finite element analysis tools are available for predicting the thermal performance of batteries, but each has limitations. In this study we describe an electro-thermal finite element approach that predicts the thermal performance of a cell or module with realistic geometry, material properties, loads, and boundary conditions.

Pesaran, A.; Vlahinos, A.; Bharathan, D.; Kim, G.-H.; Duong, T.

2005-08-01T23:59:59.000Z

422

Electro-Thermal Modeling to Improve Battery Design: Preprint  

DOE Green Energy (OSTI)

Operating temperature greatly affects the performance and life of batteries in electric and hybrid electric vehicles (HEVs). Increased attention is necessary to battery thermal management. Electrochemical models and finite element analysis tools are available for predicting the thermal performance of batteries, but each has limitations. This study describes an electro-thermal finite element approach that predicts the thermal performance of a battery cell or module with realistic geometry.

Bharathan, D.; Pesaran, A.; Kim, G.; Vlahinos, A.

2005-09-01T23:59:59.000Z

423

optimizing the forging of critical aircraft parts by the use of finite ...  

Science Conference Proceedings (OSTI)

requires the usage of finite element simulations to ensure a proper .... Due to the typical forging temperature and the low stacking fault energy of the alloys,...

424

Optics Elements for Modeling Electrostatic Lenses and Accelerator Components: III. Electrostatic Deflectors  

DOE Green Energy (OSTI)

Ion-beam optics models for simulating electrostatic prisms (deflectors) of different geometries have been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code, which includes a linear space charge model, that was originally developed to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators. Several new optical models for a number of electrostatic lenses and accelerator columns have been developed recently that allow the code to be used for modeling beamlines and accelerators with electrostatic components. The new models include a number of options for: (1) Einzel lenses, (2) accelerator columns, (3) electrostatic prisms, and (4) electrostatic quadrupoles. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The models for electrostatic prisms are described in this paper. The electrostatic prism model options allow the modeling of cylindrical, spherical, and toroidal electrostatic deflectors. The application of these models in the development of ion-beam transport systems is illustrated through the modeling of a spherical electrostatic analyzer as a component of the new low energy beamline at CAMS.

Brown, T.A.; Gillespie, G.H.

1999-10-21T23:59:59.000Z

425

Improvement in Accuracy of Prediction of Electrical Machine Constants and Generator Models for Subsynchronous Resonance Conditions, Volumes 1 and 2  

Science Conference Proceedings (OSTI)

Using the sophisticated finite-element method, researchers have produced more accurate generator models that can better predict power system performance. This method is ready for provisional use in generator analysis.

1984-04-01T23:59:59.000Z

426

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D Skyrme-Hartree-Fock Method at Finite Temperature I: Core-Collapse Supernovae  

E-Print Network (OSTI)

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. Calculations are carried out in a cubic box representing a unit cell of the locally periodic structure of the matter. A constraint is placed on the two independent components of the quadrupole moment of the neutron density in order to investigate the dependence of the total energy-density of matter on the geometry of the nuclear structure in the unit cell. This approach allows self-consistent modeling of effects such as (i) neutron drip, resulting in a neutron gas external to the nuclear structure, (ii) shell effects of bound and unbound nucleons, (iii) the variety of exotic nuclear shapes that emerge, collectively termed `nuclear pasta' and (iv) the dissolution of these structures into uniform nuclear matter as density and/or temperature increase. In part I of this work ...

Stone, W G Newton J R

2009-01-01T23:59:59.000Z

427

A Dynamic Two-Phase Flow Model of Proton Exchange Membrane Fuel Cells  

E-Print Network (OSTI)

A dynamic two phase flow model for proton exchange membrane (PEM) fuel cells is presented. The two dimensional along-the-channel model includes the two phase flow of water (gaseous and liquid) in the porous diffusion layers and in the catalyst layers, as well as the transport of the species in the gas phase. Moreover, proton and water transport in the membrane and the oxygen reduction reaction in the cathodic catalyst layer is accounted for. The discretisation of the resulting flow equations is done by a mixed finite element approach. Based on this the transport equations for the species in each phase are discretised by a finite volume scheme. The coupled mixed finite element/finite volume approach gives the spatially resolved water and gas saturation and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations for the electrons and protons are solved by using Galerkin finite element schemes.

Karsten Khn; K. Khn; Mario Ohlberger; Jrgen O. Schumacher; C. Ziegler; R. Klfkorn; Karsten Khn Ab; Mario Ohlberger Cd; Jrgen O. Schumacher A; Christoph Ziegler; Robert Klfkorn C

2003-01-01T23:59:59.000Z

428

Bernard J. Wood Jonathan D. Blundy A predictive model for rare earth element partitioning  

E-Print Network (OSTI)

of natural compositions. Propagating Dqf into the Brice model we obtain an expression for h3 o in terms and anhydrous silicate melt as a function of pressure , temperature and bulk composition . The model is based is the Young's Modulus of the site, is the gas constant and is in K. Values of iM2 obtained by ®tting

van Westrenen, Wim

429

Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model  

SciTech Connect

Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

Huang, Hai; Plummer, Mitchell; Podgorney, Robert

2013-02-01T23:59:59.000Z

430

Finite volume schemes for Boussinesq type equations  

E-Print Network (OSTI)

Finite volume schemes are commonly used to construct approximate solutions to conservation laws. In this study we extend the framework of the finite volume methods to dispersive water wave models, in particular to Boussinesq type systems. We focus mainly on the application of the method to bidirectional nonlinear, dispersive wave propagation in one space dimension. Special emphasis is given to important nonlinear phenomena such as solitary waves interactions.

Dutykh, Denys; Mitsotakis, Dimitrios

2011-01-01T23:59:59.000Z

431

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D Skyrme-Hartree-Fock Method at Finite Temperature I: Core-Collapse Supernovae  

E-Print Network (OSTI)

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. Calculations are carried out in a cubic box representing a unit cell of the locally periodic structure of the matter. A constraint is placed on the two independent components of the quadrupole moment of the neutron density in order to investigate the dependence of the total energy-density of matter on the geometry of the nuclear structure in the unit cell. This approach allows self-consistent modeling of effects such as (i) neutron drip, resulting in a neutron gas external to the nuclear structure, (ii) shell effects of bound and unbound nucleons, (iii) the variety of exotic nuclear shapes that emerge, collectively termed `nuclear pasta' and (iv) the dissolution of these structures into uniform nuclear matter as density and/or temperature increase. In part I of this work the calculation of the properties of inhomogeneous nuclear matter in the core collapse of massive stars is reported. Calculations are performed at baryon number densities of $n_{\\rm b}$ = 0.04 - 0.12 fm$^{\\rm -3}$, a proton fraction of $y_{\\rm p}=0.3$ and temperatures in the range 0 - 7.5 MeV. A wide variety of nuclear shapes are shown to emerge. It is suggested that thermodynamical properties change smoothly in the pasta regime up to the transition to uniform matter; at that transition, thermodynamic properties of the matter vary discontinuously.

W. G. Newton J. R. Stone

2009-04-30T23:59:59.000Z

432

Model-independent extraction of $|V_{tq}|$ matrix elements from top-quark measurements at hadron colliders  

E-Print Network (OSTI)

Current methods to extract the quark-mixing matrix element $|V_{tb}|$ from single-top production measurements assume that $|V_{tb}|\\gg |V_{td}|, |V_{ts}|$: top quarks decay into $b$ quarks with 100% branching fraction, s-channel single-top production is always accompanied by a $b$ quark and initial-state contributions from $d$ and $s$ quarks in the $t$-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio $R=\\frac{|V_{tb}|^{2}}{|V_{td}|^{2}+|V_{ts}|^{2}+|V_{tb}|^{2}}=0.90 \\pm 0.04$ performed by the D0 collaboration, we consider a $|V_{tb}|$ extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark mixing matrix elements $|V_{td}|$, $|V_{ts}|$, and $|V_{tb}|$ from the measurement of $R$ and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state one of which is identified as a $b$-quark jet. We constrain the $|V_{tq}|$ matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.

H. Lacker; A. Menzel; F. Spettel; D. Hirschbhl; J. Lck; F. Maltoni; W. Wagner; M. Zaro

2012-02-21T23:59:59.000Z

433

Statistical Model for Meteorological Elements Based on Local Radiosonde Measurements in Mediterranean Region  

E-Print Network (OSTI)

A comprehensive statistical model is developed for vertical profiles of the horizontal wind and temperature throughout the troposphere based on several-years radiosonde measurements of strong winds. The profiles measured under quite different atmospheric conditions exhibit qualitative similarity. A proper choice of the reference scales for the wind, temperature and altitude levels allow us to consider the measurement data as realizations of a random process with universal characteristics: means, the basic functions and parameters of standard distributions for transform coefficients of the Principal Component Analysis. The features of the atmospheric conditions are described by statistical characteristics of the wind-temperature ensemble of dimensional reference scales. The model can be useful for air pollution and safety in high-risk areas such as chemical and nuclear plants.

Virtser, A; Shtemler, Yu M

2007-01-01T23:59:59.000Z

434

It's Elemental - The Element Lithium  

NLE Websites -- All DOE Office Websites (Extended Search)

(Helium) The Periodic Table of Elements Next Element (Beryllium) Beryllium The Element Lithium Click for Isotope Data 3 Li Lithium 6.941 Atomic Number: 3 Atomic Weight: 6.941...

435

On the calculation of equilibrium thermodynamic properties and the establishment of statistical-thermodynamically-consistent finite bound-state partition functions in nonideal multicomponent plasma mixtures within the chemical model  

SciTech Connect

The problem of the calculation of equilibrium thermodynamic properties and the establishment of statistical-thermodynamically consistent finite bound-state partition functions in nonideal multicomponent plasma systems is revised within the chemical picture. The present exploration accompanied by the introduction of a generalized consistent formulation, in terms of the solution of the inverse problem, clears ambiguities and gives a better understanding of the problem on top of pointing out weaknesses and inaccuracies/inconsistencies buried in widely used models in literature.

Zaghloul, Mofreh R. [Department of Physics, College of Sciences, United Arab Emirates University, Al-Ain, 177551 (United Arab Emirates)

2010-12-15T23:59:59.000Z

436

It's Elemental - The Element Plutonium  

NLE Websites -- All DOE Office Websites (Extended Search)

Next Element (Americium) Americium The Element Plutonium Click for Isotope Data 94 Pu Plutonium 244 Atomic Number: 94 Atomic Weight: 244 Melting Point: 913 K (640C or...

437

Applications of Lagrangian Dispersion Modeling to the Analysis of Changes in the Specific Absorption of Elemental Carbon  

DOE Green Energy (OSTI)

We use a Lagrangian dispersion model driven by a mesoscale model with four-dimensional data assimilation to simulate the dispersion of elemental carbon (EC) over a region encompassing Mexico City and its surroundings, the study domain for the 2006 MAX-MEX experiment, which was a component of the MILAGRO campaign. The results are used to identify periods when biomass burning was likely to have had a significant impact on the concentrations of elemental carbon at two sites, T1 and T2, downwind of the city, and when emissions from the Mexico City Metropolitan Area (MCMA) were likely to have been more important. They are also used to estimate the median ages of EC affecting the specific absorption of light, aABS, at 870 nm as well as to identify periods when the urban plume from the MCMA was likely to have been advected over T1 and T2. Values of aABS at T1, the nearer of the two sites to Mexico City, were smaller at night and increased rapidly after mid-morning, peaking in the mid-afternoon. The behavior is attributed to the coating of aerosols with substances such as sulfate or organic carbon during daylight hours, but such coating appears to be limited or absent at night. Evidence for this is provided by scanning electron microscope images of aerosols collected at three sampling sites. During daylight hours the values of aABS did not increase with aerosol age for median ages in the range of 1-4 hours. There is some evidence for absorption increasing as aerosols were advected from T1 to T2 but the statistical significance of that result is not strong.

Doran, J. C.; Fast, Jerome D.; Barnard, James C.; Laskin, Alexander; Desyaterik, Yury; Gilles, Marry K.; Hopkins, Rebecca J.

2008-03-07T23:59:59.000Z

438

Finite groups and quantum physics  

Science Conference Proceedings (OSTI)

Concepts of quantum theory are considered from the constructive 'finite' point of view. The introduction of a continuum or other actual infinities in physics destroys constructiveness without any need for them in describing empirical observations. It is shown that quantum behavior is a natural consequence of symmetries of dynamical systems. The underlying reason is that it is impossible in principle to trace the identity of indistinguishable objects in their evolution-only information about invariant statements and values concerning such objects is available. General mathematical arguments indicate that any quantum dynamics is reducible to a sequence of permutations. Quantum phenomena, such as interference, arise in invariant subspaces of permutation representations of the symmetry group of a dynamical system. Observable quantities can be expressed in terms of permutation invariants. It is shown that nonconstructive number systems, such as complex numbers, are not needed for describing quantum phenomena. It is sufficient to employ cyclotomic numbers-a minimal extension of natural numbers that is appropriate for quantum mechanics. The use of finite groups in physics, which underlies the present approach, has an additional motivation. Numerous experiments and observations in the particle physics suggest the importance of finite groups of relatively small orders in some fundamental processes. The origin of these groups is unclear within the currently accepted theories-in particular, within the Standard Model.

Kornyak, V. V., E-mail: kornyak@jinr.ru [Joint Institute for Nuclear Physics, Laboratory of Information Tecnnologies (Russian Federation)

2013-02-15T23:59:59.000Z

439

Flawed Assumptions, Models and Decision Making: Misconceptions Concerning Human Elements in Complex System  

SciTech Connect

The history of high consequence accidents is rich with events wherein the actions, or inaction, of humans was critical to the sequence of events preceding the accident. Moreover, it has been reported that human error may contribute to 80% of accidents, if not more (dougherty and Fragola, 1988). Within the safety community, this reality is widely recognized and there is a substantially greater awareness of the human contribution to system safety today than has ever existed in the past. Despite these facts, and some measurable reduction in accident rates, when accidents do occur, there is a common lament. No matter how hard we try, we continue to have accidents. Accompanying this lament, there is often bewilderment expressed in statements such as, ''There's no explanation for why he/she did what they did''. It is believed that these statements are a symptom of inadequacies in how they think about humans and their role within technological systems. In particular, while there has never been a greater awareness of human factors, conceptual models of human involvement in engineered systems are often incomplete and in some cases, inaccurate.

FORSYTHE,JAMES C.; WENNER,CAREN A.

1999-11-03T23:59:59.000Z

440

A Shell/3D Modeling Technique for the Analysis of Delaminated Composite Laminates  

E-Print Network (OSTI)

A shell/3D modeling technique developed which local three-dimensional solid finite element model used only immediate vicinity delamination front. The goal was combine the accuracy the three-dimensional solution with the computational efficiency plate shell finite element model. Multi-point constraints provided kinematically compatible interface between local three-dimensional model global structural model which has been meshed with plate shell finite elements. Double Cantilever Beam (DCB), Notched Flexure (ENF), Single Bending (SLB) specimens were modeled using shell/3D technique study feasibility pure mode (DCB), mode (ENF) mixed mode I/II (SLB) cases. Mixed mode strain energy release rate distributions were computed across the width specimens using virtual crack closure technique. Specimens a unidirectional layup and with multidirectional layup where delamination located between two non-zero degree plies were simulated. For a local three-dimensional model, extending minimum about thr...

Ronald Krueger; T. Kevin O' Brien

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling finite element" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Automated modeling of modular robotic configurations  

Science Conference Proceedings (OSTI)

This research presents an automated method to build kinematic and dynamic models for assembling modular components of modular robotic systems. By comparison with other approaches, the proposed method is applicable to any robotic configuration with serial, ... Keywords: Automatic modeling, Computer-aided design, Configuration design, Finite element method, Modular architecture, Modular robotic system, Reconfigurable robot

Z. M. Bi; W. A. Gruver; W. J. Zhang; S. Y. T. Lang

2006-12-01T23:59:59.000Z

442

Efficient numerical modeling of borehole heat exchangers  

Science Conference Proceedings (OSTI)

This paper presents a finite element modeling technique for double U-tube borehole heat exchangers (BHE) and the surrounding soil mass. Focus is placed on presenting numerical analyses describing the capability of a BHE model, previously reported, to ... Keywords: BHE, Geothermal heat pumps, Geothermic, Heat transfer, Space heating

R. Al-Khoury; T. Klbel; R. Schramedei

2010-10-01T23:59:59.000Z

443

The Use of Finite-Volume Methods for Atmospheric Advection of Trace Species. Part I: Test of Various Formulations in a General Circulation Model  

Science Conference Proceedings (OSTI)

In the context of advection of trace species by 3D atmospheric flows, a comparative test of a hierarchy of finite volume transport schemes initially derived by B. Van Leer is presented. Those schemes are conservative by construction and Van Leer ...

Frdric Hourdin; Alexandre Armengaud

1999-05-01T23:59:59.000Z

444

Toward free-surface modeling of planing vessels: simulation of the Fridsma hull using ALE-VMS  

Science Conference Proceedings (OSTI)

In this paper we focus on a class of applications involving surface vessels moving at high speeds, or "planing". We introduce a Fridsma planing hull benchmark problem, and simulate it using the finite-element-based ALE-VMS (Bazilevs et al. in Math Models ... Keywords: ALE-VMS, Finite elements, Fluid/rigid---body interaction, Free-surface flow, Fridsma planing hull, Level set, Ship hydrodynamics

I. Akkerman; J. Dunaway; J. Kvandal; J. Spinks; Y. Bazilevs

2012-12-01T23:59:59.000Z

445

How to choose the simulation model for computer experiments: a local approach  

Science Conference Proceedings (OSTI)

In many scientific areas, non-stochastic simulation models such as finite element simulations replace real experiments. A common approach is to fit a meta-model, for example a Gaussian process model, a radial basis function interpolation, or a kernel ... Keywords: Gaussian process model, computer code validation, computer experiment, kernel interpolation, sheet metal forming

Thomas Mhlenstdt; Marco Gsling; Sonja Kuhnt

2012-07-01T23:59:59.000Z

446

Calibration of a FE model of masonry shear panels strengthened by metal sheathing  

Science Conference Proceedings (OSTI)

In order to calibrate advanced FE Model experimental tests on masonry wall panel specimens in shear as well as on some panels strengthened by ductile steel are used. Application of finite element material models to simulate the behavior of masonry is ... Keywords: FE model, innovative retrofitting techniques, masonry shear panels, material models

A. Dogariu; F. Campitiello

2010-04-01T23:59:59.000Z

447

It's Elemental - Element Concentration Game  

NLE Websites -- All DOE Office Websites (Extended Search)

symbols of the elements. After you have had time to study the cards, the computer will flip them over and ask you to find a particular element. Click on the card that contains...

448

Modelling of heat transfer at glass/mould interface in press and blow forming processes  

Science Conference Proceedings (OSTI)

Numerical models may play an important role in the optimization of the quality of hollow-ware glass articles in glass industry. Due to the complexity of the phenomena involved a coupling between thermal and mechanical aspects is crucial. One of the key ... Keywords: Finite elements, Glass forming, Heat conduction, Heat transfer coefficient, Interface element, Press/blow process

Sbastien Grgoire; Jos M. A. Csar de S; Philippe Moreau; Dominique Lochegnies

2007-08-01T23:59:59.000Z

449

Finite temperature field theory and phase transitions  

E-Print Network (OSTI)

We review different aspects of field theory at zero and finite temperature, related to the theory of phase transitions. We discuss different renormalization conditions for the effective potential at zero temperature, emphasizing in particular the MS-bar renormalization scheme. Finite temperature field theory is discussed in the real and imaginary time formalisms, showing their equivalence in simple examples. Bubble nucleation by thermal tunneling, and the subsequent development of the phase transition is described in some detail. Some attention is also devoted to the breakdown of the perturbative expansion and the infrared problem in the finite temperature field theory. Finally the application to baryogenesis at the electroweak phase transition is done in the Standard Model and in the Minimal Supersymmetric Standard Model. In all cases we have translated the condition of not washing out any previously generated baryon asymmetry by upper bounds on the Higgs mass.

Mariano Quiros

1999-01-14T23:59:59.000Z

450

On two-dimensional pattern matching by finite automata  

Science Conference Proceedings (OSTI)

This paper presents a general concept of two-dimensional pattern matching using conventional (one-dimensional) finite automata. Then two particular models and methods, implementations of the general principle, are presented. The first of these two models ...

Jan d'rek; Bo?ivoj Melichar

2005-06-01T23:59:59.000Z

451

It's Elemental - The Element Europium  

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Samarium Samarium Previous Element (Samarium) The Periodic Table of Elements Next Element (Gadolinium) Gadolinium The Element Europium [Click for Isotope Data] 63 Eu Europium 151.964 Atomic Number: 63 Atomic Weight: 151.964 Melting Point: 1095 K (822°C or 1512°F) Boiling Point: 1802 K (1529°C or 2784°F) Density: 5.24 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 6 Group Number: none Group Name: Lanthanide What's in a name? Named after the continent of Europe. Say what? Europium is pronounced as yoo-RO-pee-em. History and Uses: Europium was discovered by Eugène-Antole Demarçay, a French chemist, in 1896. Demarçay suspected that samples of a recently discovered element, samarium, were contaminated with an unknown element. He was able to produce

452

It's Elemental - The Element Potassium  

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Argon Argon Previous Element (Argon) The Periodic Table of Elements Next Element (Calcium) Calcium The Element Potassium [Click for Isotope Data] 19 K Potassium 39.0983 Atomic Number: 19 Atomic Weight: 39.0983 Melting Point: 336.53 K (63.38°C or 146.08°F) Boiling Point: 1032 K (759°C or 1398°F) Density: 0.89 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 4 Group Number: 1 Group Name: Alkali Metal What's in a name? From the English word potash. Potassium's chemical symbol comes from the Latin word for alkali, kalium. Say what? Potassium is pronounced as poh-TASS-ee-em. History and Uses: Although potassium is the eighth most abundant element on earth and comprises about 2.1% of the earth's crust, it is a very reactive element

453

It's Elemental - The Element Sulfur  

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Phosphorus Phosphorus Previous Element (Phosphorus) The Periodic Table of Elements Next Element (Chlorine) Chlorine The Element Sulfur [Click for Isotope Data] 16 S Sulfur 32.065 Atomic Number: 16 Atomic Weight: 32.065 Melting Point: 388.36 K (115.21°C or 239.38°F) Boiling Point: 717.75 K (444.60°C or 832.28°F) Density: 2.067 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Non-metal Period Number: 3 Group Number: 16 Group Name: Chalcogen What's in a name? From the Sanskrit word sulvere and the Latin word sulphurium. Say what? Sulfur is pronounced as SUL-fer. History and Uses: Sulfur, the tenth most abundant element in the universe, has been known since ancient times. Sometime around 1777, Antoine Lavoisier convinced the rest of the scientific community that sulfur was an element. Sulfur is a

454

It's Elemental - The Element Magnesium  

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Sodium Sodium Previous Element (Sodium) The Periodic Table of Elements Next Element (Aluminum) Aluminum The Element Magnesium [Click for Isotope Data] 12 Mg Magnesium 24.3050 Atomic Number: 12 Atomic Weight: 24.3050 Melting Point: 923 K (650°C or 1202°F) Boiling Point: 1363 K (1090°C or 1994°F) Density: 1.74 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 3 Group Number: 2 Group Name: Alkaline Earth Metal What's in a name? For Magnesia, a district in the region of Thessaly, Greece. Say what? Magnesium is pronounced as mag-NEE-zhi-em. History and Uses: Although it is the eighth most abundant element in the universe and the seventh most abundant element in the earth's crust, magnesium is never found free in nature. Magnesium was first isolated by Sir Humphry Davy, an

455

Twisted mass finite volume effects  

SciTech Connect

We calculate finite-volume effects on the pion masses and decay constant in twisted mass lattice QCD at finite lattice spacing. We show that the lighter neutral pion in twisted mass lattice QCD gives rise to finite-volume effects that are exponentially enhanced when compared to those arising from the heavier charged pions. We demonstrate that the recent two flavor twisted mass lattice data can be better fitted when twisted mass effects in finite-volume corrections are taken into account.

Colangelo, Gilberto; Wenger, Urs; Wu, Jackson M. S. [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland)

2010-08-01T23:59:59.000Z

456

A Statistical Motion Model Based on Biomechanical Simulations for Data Fusion during Image-Guided Prostate Interventions  

Science Conference Proceedings (OSTI)

A method is described for generating a patient-specific, statistical motion model (SMM) of the prostate gland. Finite element analysis (FEA) is used to simulate the motion of the gland using an ultrasound-based 3D FE model over a range of plausible boundary ... Keywords: Transrectal ultrasound, biomechanical modelling, minimally-invasive interventions, prostate, statistical shape modelling

Yipeng Hu; Dominic Morgan; Hashim Uddin Ahmed; Doug Pends; Mahua Sahu; Clare Allen; Mark Emberton; David Hawkes; Dean Barratt

2008-09-01T23:59:59.000Z

457

Modeling, Design and Construction of Articulated Hand for Use in Prosthetics, with Adaptive Control in Neural Networks Based on Mathematical Model for Finger  

Science Conference Proceedings (OSTI)

An Articulated hand model was designed and built by CAD-CAM software, analyzed by finite element in the structure; the hand was made for a 3D printer in a first time, the construction of each finger suggested a mathematical model that describes the Inertia ... Keywords: Prosthetics, Adaptive Control by Neural Networks, Myoelectric Signal, Mathematical Model of 3G

Emilio Soto; Oscar Baez; Sergio Sosa

2010-11-01T23:59:59.000Z

458

Efficient double beta decay nuclear matrix elements computations  

SciTech Connect

We have developed a shell model code for the accurate computation of the two-body matrix elements of the transition operators involved in the neutrinoless double beta decay. This code features coupled cluster method short-range correlations with Jastrow-like functions, finite nucleon size effect and higher order nucleon current corrections. We present the results obtained for {sup 48}Ca and {sup 82}Se, then we compare them with other results in the literature. In the case of {sup 48}Ca, we also study the contributions of the included effects and find good agreement with other published results.

Neacsu, Andrei [Horia Hulubei Foundation (FHH) 407 Atomistilor, Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) 30 Reactorului, Magurele-Bucharest 077125 (Romania)

2012-11-20T23:59:59.000Z

459

Free Rossby Wave Instability at Finite Amplitude  

Science Conference Proceedings (OSTI)

The finite-amplitude evolution of the instability of a nonparallel basic-state flow and the basic state are studied. The basic state consists of a free Rossby wave in an inviscid, barotropic beta-plane model. The method of multiple time scales is ...

Richard C. Deininger

1982-03-01T23:59:59.000Z

460

Steady-State Diagnostic Model of the New York Bight  

Science Conference Proceedings (OSTI)

A qualitative evaluation is made of the output from a finite-element, steady-state diagnostic model to observed time-averaged currents. The model uses a vorticity balance equation with linear bottom friction and inputs observations of near-bottom ...

Gregory Han; Donald V. Hansen; Jerry A. Galt

1980-12-01T23:59:59.000Z

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461

Computational challenges in large-scale air pollution modelling  

Science Conference Proceedings (OSTI)

Many difficulties must be overcome when large-scale air pollution models are treated numerically, because the physical and chemical processes in the atmosphere are very fast. This is why it is necessary to use a large space domain in order ... Keywords: air pollution models, finite elements, ordinary differential equations, parallel computational, partial differential equations, quasi-steady-state-approximation

Tzvetan Ostromsky; Wojciech Owczarz; Zahari Zlatev

2001-06-01T23:59:59.000Z

462

It's Elemental - The Element Technetium  

NLE Websites -- All DOE Office Websites (Extended Search)

Molybdenum Molybdenum Previous Element (Molybdenum) The Periodic Table of Elements Next Element (Ruthenium) Ruthenium The Element Technetium [Click for Isotope Data] 43 Tc Technetium 98 Atomic Number: 43 Atomic Weight: 98 Melting Point: 2430 K (2157°C or 3915°F) Boiling Point: 4538 K (4265°C or 7709°F) Density: 11 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 5 Group Number: 7 Group Name: none Radioactive and Artificially Produced What's in a name? From the Greek word for artificial, technetos. Say what? Technetium is pronounced as tek-NEE-she-em. History and Uses: Technetium was the first artificially produced element. It was isolated by Carlo Perrier and Emilio Segrè in 1937. Technetium was created by bombarding molybdenum atoms with deuterons that had been accelerated by a

463

It's Elemental - The Element Cobalt  

NLE Websites -- All DOE Office Websites (Extended Search)

Iron Iron Previous Element (Iron) The Periodic Table of Elements Next Element (Nickel) Nickel The Element Cobalt [Click for Isotope Data] 27 Co Cobalt 58.933195 Atomic Number: 27 Atomic Weight: 58.933195 Melting Point: 1768 K (1495°C or 2723°F) Boiling Point: 3200 K (2927°C or 5301°F) Density: 8.86 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 4 Group Number: 9 Group Name: none What's in a name? From the German word for goblin or evil spirit, kobald and the Greek word for mine, cobalos. Say what? Cobalt is pronounced as KO-bolt. History and Uses: Cobalt was discovered by Georg Brandt, a Swedish chemist, in 1739. Brandt was attempting to prove that the ability of certain minerals to color glass blue was due to an unknown element and not to bismuth, as was commonly

464

It's Elemental - The Element Bromine  

NLE Websites -- All DOE Office Websites (Extended Search)

Selenium Selenium Previous Element (Selenium) The Periodic Table of Elements Next Element (Krypton) Krypton The Element Bromine [Click for Isotope Data] 35 Br Bromine 79.904 Atomic Number: 35 Atomic Weight: 79.904 Melting Point: 265.95 K (-7.2°C or 19.0°F) Boiling Point: 331.95 K (58.8°C or 137.8°F) Density: 3.11 grams per cubic centimeter Phase at Room Temperature: Liquid Element Classification: Non-metal Period Number: 4 Group Number: 17 Group Name: Halogen What's in a name? From the Greek word for stench, bromos. Say what? Bromine is pronounced as BRO-meen. History and Uses: The only nonmetallic element that is a liquid at normal room temperatures, bromine was produced by Carl Löwig, a young chemistry student, the summer before starting his freshman year at Heidelberg. When he showed his

465

It's Elemental - The Element Oxygen  

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Nitrogen Nitrogen Previous Element (Nitrogen) The Periodic Table of Elements Next Element (Fluorine) Fluorine The Element Oxygen [Click for Isotope Data] 8 O Oxygen 15.9994 Atomic Number: 8 Atomic Weight: 15.9994 Melting Point: 54.36 K (-218.79°C or -361.82°F) Boiling Point: 90.20 K (-182.95°C or -297.31°F) Density: 0.001429 grams per cubic centimeter Phase at Room Temperature: Gas Element Classification: Non-metal Period Number: 2 Group Number: 16 Group Name: Chalcogen What's in a name? From the greek words oxys and genes, which together mean "acid forming." Say what? Oxygen is pronounced as OK-si-jen. History and Uses: Oxygen had been produced by several chemists prior to its discovery in 1774, but they failed to recognize it as a distinct element. Joseph

466

It's Elemental - The Element Nitrogen  

NLE Websites -- All DOE Office Websites (Extended Search)

Carbon Carbon Previous Element (Carbon) The Periodic Table of Elements Next Element (Oxygen) Oxygen The Element Nitrogen [Click for Isotope Data] 7 N Nitrogen 14.0067 Atomic Number: 7 Atomic Weight: 14.0067 Melting Point: 63.15 K (-210.00°C or -346.00°F) Boiling Point: 77.36 K (-195.79°C or -320.44°F) Density: 0.0012506 grams per cubic centimeter Phase at Room Temperature: Gas Element Classification: Non-metal Period Number: 2 Group Number: 15 Group Name: Pnictogen What's in a name? From the Greek words nitron and genes, which together mean "saltpetre forming." Say what? Nitrogen is pronounced as NYE-treh-gen. History and Uses: Nitrogen was discovered by the Scottish physician Daniel Rutherford in 1772. It is the fifth most abundant element in the universe and makes up

467

It's Elemental - The Element Sodium  

NLE Websites -- All DOE Office Websites (Extended Search)

Neon Neon Previous Element (Neon) The Periodic Table of Elements Next Element (Magnesium) Magnesium The Element Sodium [Click for Isotope Data] 11 Na Sodium 22.98976928 Atomic Number: 11 Atomic Weight: 22.98976928 Melting Point: 370.95 K (97.80°C or 208.04°F) Boiling Point: 1156 K (883°C or 1621°F) Density: 0.97 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 3 Group Number: 1 Group Name: Alkali Metal What's in a name? From the English word soda and from the Medieval Latin word sodanum, which means "headache remedy." Sodium's chemical symbol comes from the Latin word for sodium carbonate, natrium. Say what? Sodium is pronounced as SO-dee-em. History and Uses: Although sodium is the sixth most abundant element on earth and comprises

468

It's Elemental - The Element Francium  

NLE Websites -- All DOE Office Websites (Extended Search)

Radon Radon Previous Element (Radon) The Periodic Table of Elements Next Element (Radium) Radium The Element Francium [Click for Isotope Data] 87 Fr Francium 223 Atomic Number: 87 Atomic Weight: 223 Melting Point: 300 K (27°C or 81°F) Boiling Point: Unknown Density: Unknown Phase at Room Temperature: Solid Element Classification: Metal Period Number: 7 Group Number: 1 Group Name: Alkali Metal Radioactive What's in a name? Named for the country of France. Say what? Francium is pronounced as FRAN-see-em. History and Uses: Francium was discovered by Marguerite Catherine Perey, a French chemist, in 1939 while analyzing actinium's decay sequence. Although considered a natural element, scientists estimate that there is no more than one ounce of francium in the earth's crust at one time. Since there is so little

469

It's Elemental - The Element Phosphorus  

NLE Websites -- All DOE Office Websites (Extended Search)

Silicon Silicon Previous Element (Silicon) The Periodic Table of Elements Next Element (Sulfur) Sulfur The Element Phosphorus [Click for Isotope Data] 15 P Phosphorus 30.973762 Atomic Number: 15 Atomic Weight: 30.973762 Melting Point: 317.30 K (44.15°C or 111.47°F) Boiling Point: 553.65 K (280.5°C or 536.9°F) Density: 1.82 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Non-metal Period Number: 3 Group Number: 15 Group Name: Pnictogen What's in a name? From the Greek word for light bearing, phosphoros. Say what? Phosphorus is pronounced as FOS-fer-es. History and Uses: In what is perhaps the most disgusting method of discovering an element, phosphorus was first isolated in 1669 by Hennig Brand, a German physician and alchemist, by boiling, filtering and otherwise processing as many as 60

470

It's Elemental - The Element Cerium  

NLE Websites -- All DOE Office Websites (Extended Search)

Lanthanum Lanthanum Previous Element (Lanthanum) The Periodic Table of Elements Next Element (Praseodymium) Praseodymium The Element Cerium [Click for Isotope Data] 58 Ce Cerium 140.116 Atomic Number: 58 Atomic Weight: 140.116 Melting Point: 1071 K (798°C or 1468°F) Boiling Point: 3697 K (3424°C or 6195°F) Density: 6.770 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 6 Group Number: none Group Name: Lanthanide What's in a name? Named for the asteroid Ceres. Say what? Cerium is pronounced as SER-ee-em. History and Uses: Cerium was discovered by Jöns Jacob Berzelius and Wilhelm von Hisinger, Swedish chemists, and independently by Martin Heinrich Klaproth, a German chemist, in 1803. Cerium is the most abundant of the rare earth elements

471

It's Elemental - The Element Indium  

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Cadmium Cadmium Previous Element (Cadmium) The Periodic Table of Elements Next Element (Tin) Tin The Element Indium [Click for Isotope Data] 49 In Indium 114.818 Atomic Number: 49 Atomic Weight: 114.818 Melting Point: 429.75 K (156.60°C or 313.88°F) Boiling Point: 2345 K (2072°C or 3762°F) Density: 7.31 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 5 Group Number: 13 Group Name: none What's in a name? Named after the bright indigo line in its spectrum. Say what? Indium is pronounced as IN-dee-em. History and Uses: Indium was discovered by the German chemists Ferdinand Reich and Hieronymus Theodor Richter in 1863. Reich and Richter had been looking for traces of the element thallium in samples of zinc ores. A brilliant indigo line in

472

It's Elemental - The Element Neon  

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Fluorine Fluorine Previous Element (Fluorine) The Periodic Table of Elements Next Element (Sodium) Sodium The Element Neon [Click for Isotope Data] 10 Ne Neon 20.1797 Atomic Number: 10 Atomic Weight: 20.1797 Melting Point: 24.56 K (-248.59°C or -415.46°F) Boiling Point: 27.07 K (-246.08°C or -410.94°F) Density: 0.0008999 grams per cubic centimeter Phase at Room Temperature: Gas Element Classification: Non-metal Period Number: 2 Group Number: 18 Group Name: Noble Gas What's in a name? From the Greek word for new, neos. Say what? Neon is pronounced as NEE-on. History and Uses: Neon was discovered by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, shortly after their discovery of the element krypton in 1898. Like krypton, neon was discovered through the

473

It's Elemental - The Element Manganese  

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Chromium Chromium Previous Element (Chromium) The Periodic Table of Elements Next Element (Iron) Iron The Element Manganese [Click for Isotope Data] 25 Mn Manganese 54.938045 Atomic Number: 25 Atomic Weight: 54.938045 Melting Point: 1519 K (1246°C or 2275°F) Boiling Point: 2334 K (2061°C or 3742°F) Density: 7.3 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 4 Group Number: 7 Group Name: none What's in a name? From the Latin word for magnet, magnes. Say what? Manganese is pronounced as MAN-ge-nees. History and Uses: Proposed to be an element by Carl Wilhelm Scheele in 1774, manganese was discovered by Johan Gottlieb Gahn, a Swedish chemist, by heating the mineral pyrolusite (MnO2) in the presence of charcoal later that year.