ME 872 -Finite Element Methods Spring 2014
Diaz, Alejandro
Element Method: Linear Static and Dynamic Finite Element Analysis (Dover Civil and Mechanical Engineering problems Special topics: Lagrange multipliers, adaptive finite elements, sensitivity analysis, nonlinearME 872 - Finite Element Methods Spring 2014 Catalog Description: Theory and application
Combined Finite Element --Finite Volume Method ( Convergence Analysis )
Magdeburg, Universität
Combined Finite Element -- Finite Volume Method ( Convergence Analysis ) M'aria Luk idea is to combine finite volume and finite element methods in an appropriate way. Thus nonlinear grid. Diffusion terms are discretized by the conforming piecewise linear finite element method
Generalized finite element method for Helmholtz equation
Hidajat, Realino Lulie
2009-05-15T23:59:59.000Z
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...
Discontinuous finite element methods for particle transport problems
Stone, Hiromi
2002-01-01T23:59:59.000Z
We develop, analyze, and test a new discontinuous finite element method (DFEM), namely the piece-wise linear discontinuous (PWLD) method for transport problems. We compare the PWLD method against the rational finite element (RFE) method. We show...
Math/AMath 595: Finite Element Methods (Winter 2001)
Stein, William
for Elliptic Problems by Philippe G. Ciarlet (1978). 3. An Analysis of the Finite Element Method by GilbertMath/AMath 595: Finite Element Methods (Winter 2001) Lectures: MW 3:30{4:50, room 121 RAI Professor Element Methods by Susanne C. Brenner and L. Ridgway Scott (1994). 2. The Finite Element Method
Finite Element Methods for Radiosity \\Lambda Paul S. Heckbert
Treuille, Adrien
Finite Element Methods for Radiosity \\Lambda Paul S. Heckbert Carnegie Mellon University Global global illu mination: finite element methods and Monte Carlo methods. The former approach yields radiosity methods and the latter approach yields ray tracing methods, generally speaking. Finite element
ANALYSIS OF SOME MOVING SPACETIME FINITE ELEMENT METHODS \\Lambda
Bank, Randolph E.
ANALYSIS OF SOME MOVING SPACETIME FINITE ELEMENT METHODS \\Lambda RANDOLPH E. BANK y AND RAFAEL F. SANTOS z Abstract. Two spacetime finite element methods for solving timedependent partial differential equations are defined and analyzed. The methods are based on the use of isoparametric finite elements
AN ADAPTIVE SURFACE FINITE ELEMENT METHOD BASED ON VOLUME MESHES
Demlow, Alan
studied in this paper. The paper of Dziuk [12] contains the first analysis of a finite element methodAN ADAPTIVE SURFACE FINITE ELEMENT METHOD BASED ON VOLUME MESHES ALAN DEMLOW AND MAXIM A. OLSHANSKII Abstract. In this paper we define an adaptive version of a recently introduced finite element
A finite element method and the method of finite spheres enriched for analysis of wave propagations
Ham, Seounghyun, 1982-
2014-01-01T23:59:59.000Z
The objective of this thesis is to present a finite element method and the method of finite spheres enriched for the solution of various wave propagation problems. The first part of this thesis is to present an enriched ...
Complex Wavenumber Fourier Analysis of the PVersion Finite Element Method
Thompson, Lonny L.
Complex Wavenumber Fourier Analysis of the PVersion Finite Element Method Lonny L. Thompson wave solutions. This type of analysis amounts to a discrete Fourier synthesis of the finite element bands in the context of finite element analysis were not fully understood, although there is some
Analysis of a Combined Barycentric Finite Volume --Nonconforming Finite Element Method for Nonlinear
Dolejsi, Vit
Analysis of a Combined Barycentric Finite Volume -- Nonconforming Finite Element Method, the theoretical analysis of the combined finite volume -- finite element method has been carried out for the case term is discretized by piecewise linear nonconforming triangular finite elements. Under the assumption
Adaptive finite element method for eddy current problems
Adaptive finite element method for eddy current problems. In this chapter we shall discuss Maxwell's equations at very low frequencies. We also refer to [bo98 ...
ADAPTIVE FINITE ELEMENT FREQUENCY DOMAIN METHOD FOR EDDY CURRENT PROBLEMS
Zheng, Weiying
ADAPTIVE FINITE ELEMENT FREQUENCY DOMAIN METHOD FOR EDDY CURRENT PROBLEMS WEIYING ZHENG-harmonic eddy current problems in the case of three-dimensional isotropic and linear materials. We adopt. Time-harmonic Maxwell's equations, eddy current, adaptive finite element method, multiply connected
LEAST-SQUARES FINITE ELEMENT METHODS FOR OPTIMALITY SYSTEMS ARISING
Bochev, Pavel
LEAST-SQUARES FINITE ELEMENT METHODS FOR OPTIMALITY SYSTEMS ARISING IN OPTIMIZATION AND CONTROL control problems for systems governed by linear, elliptic partial differential equations is considered modern least-squares finite element methods for the solution of the optimality systems. The matrix equa
A Note on the Finite Element Method with Singular Basis Functions
Kaneko, Hideaki
finite element analysis that incorporates singular element functions. A need for introducing * *some singular elements as part of basis functions in certain finite element analysis arises o* *ut A Note on the Finite Element Method with Singular Basis
An application of stochastic finite element method in structural reliabiity
Agrawal, Sanjay
1993-01-01T23:59:59.000Z
AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SAN JAY AGRAWAL Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1993 Major Subject: Civil Engineering AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SANJAY AGRAWAL Approved as to style and content by: Kostas apadimitriou (Chair of Committee) John M...
Coupled finite element and meshfree method Application to wide-flange steel sections
Yaw, Louis L.
, 2007 Yaw, Kunnath & Sukumar Meshfree Inelastic Frame Analysis #12;Motivation Coupled finite element Inelastic Frame Analysis #12;Motivation Coupled finite element and meshfree method Application to wide & Sukumar Meshfree Inelastic Frame Analysis #12;Motivation Coupled finite element and meshfree method
Control-volume mixed finite element methods
1998-01-23T23:59:59.000Z
As techniques of reservoir description become more sophisticated, .... [12] have applied these methods to petroleum reservoir ...... a concern in principle because the curvilinear faces, normal vectors, and fluxes are ..... Proceedings of the 11th SPE Symposium on Reservoir Simulation (Society of Petroleum Engineers,.
Discontinuous Galerkin finite element methods for gradient plasticity.
Garikipati, Krishna. (University of Michigan, Ann Arbor, MI); Ostien, Jakob T.
2010-10-01T23:59:59.000Z
In this report we apply discontinuous Galerkin finite element methods to the equations of an incompatibility based formulation of gradient plasticity. The presentation is motivated with a brief overview of the description of dislocations within a crystal lattice. A tensor representing a measure of the incompatibility with the lattice is used in the formulation of a gradient plasticity model. This model is cast in a variational formulation, and discontinuous Galerkin machinery is employed to implement the formulation into a finite element code. Finally numerical examples of the model are shown.
A ROBUST FINITE ELEMENT METHOD FOR DARCY--STOKES FLOW
Winther, Ragnar
. When # = 0 the first equation in (1.1) has the form of Darcy's law for flow in a homogeneous porousA ROBUST FINITE ELEMENT METHOD FOR DARCY--STOKES FLOW KENT ANDRE MARDAL, XUE--CHENG TAI, AND RAGNAR the perturbation parameter is large, while it degenerates to a mixed formulation of Poisson's equation
Course Announcement: Spring 2015 Finite Element Methods for Engineers
.v.griffiths@mines.edu Web: www.mines.edu/~vgriffit This course combines finite element theory with practical programming
FINITE ELEMENT METHOD IN FLUID MECHANICS & HEAT TRANSFER
Camci, Cengiz
completed this course should be able to perform quick analysis of small problems using the finite element of Fluid Mechanics and Heat Transfer An Introduction to Finite Element Analysis Using "Galerkin Weak of Euler's Equation in Finite Element Analysis Generalized Form of Euler's Equation in Three Dimensional
THE BUBBLE TRANSFORM: A NEW TOOL FOR ANALYSIS OF FINITE ELEMENT METHODS
THE BUBBLE TRANSFORM: A NEW TOOL FOR ANALYSIS OF FINITE ELEMENT METHODS RICHARD S. FALK AND RAGNAR estimates for various finite element methods. In particular, for the analysis of mixed finite element be very useful, but hard to construct, is the analysis of the so-called p-version of the finite element
An efficient finite element method applied to quantum billiard systems
Woo-Sik Son; Sunghwan Rim; Chil-Min Kim
2009-02-25T23:59:59.000Z
An efficient finite element method (FEM) for calculating eigenvalues and eigenfunctions of quantum billiard systems is presented. We consider the FEM based on triangular $C_1$ continuity quartic interpolation. Various shapes of quantum billiards including an integrable unit circle are treated. The numerical results show that the applied method provides accurate set of eigenvalues exceeding a thousand levels for any shape of quantum billiards on a personal computer. Comparison with the results from the FEM based on well-known $C_0$ continuity quadratic interpolation proves the efficiency of the method.
Finite Element Methods for Nonlinear Acoustics in Fluids
The non- linear terms in these wave equations imply that the sound speed ... ics, the finite element formulation of nonlinear acoustic equations for fluids has.
Adaptive Finite Element Method for Time-domain Maxwell's ...
Shuhao Cao supervised under Professor Cai
2013-10-31T23:59:59.000Z
Oct 11, 2013 ... Avoiding the pollution of the finite element approximation, a.k.a. the spurious modes. Lowest-order element's DoFs associated with edges, and.
THE STEFAN PROBLEM: A STOCHASTIC ANALYSIS USING THE EXTENDED FINITE ELEMENT METHOD
Zabaras, Nicholas J.
THE STEFAN PROBLEM: A STOCHASTIC ANALYSIS USING THE EXTENDED FINITE ELEMENT METHOD Baskar these uncertainties in a stochastic sense using the extended finite element method as the deterministic solution convection using the extended finite element method (XFEM) and level set methods," Journal of Computational
Adaptive Finite Element Method for Solving the Exact Kohn-Sham...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Finite Element Method for Solving the Exact Kohn-Sham Equation of Density Functional Theory. Adaptive Finite Element Method for Solving the Exact Kohn-Sham Equation of Density...
Stabilized finite element methods with fast iterative solution ...
2003-04-11T23:59:59.000Z
Computer methods in applied mechanics and engineering. Stabilized finite ... Department of Mathemutics, Purdue Universi@, 1395 Mathematical Science ...
ANALYSIS OF A FINITE VOLUME ELEMENT METHOD FOR THE STOKES PROBLEM
Paris-Sud XI, Université de
ANALYSIS OF A FINITE VOLUME ELEMENT METHOD FOR THE STOKES PROBLEM ALFIO QUARTERONI, AND RICARDO stabilization, finite volume element method, a priori error estimates, superconvergence analysis. CMCS RUIZ BAIER Abstract. In this paper we propose a stabilized conforming finite volume element method
Xia, Yi-Ming
2015-01-01T23:59:59.000Z
A locking-free rectangular Mindlin plate element with a new multi-resolution analysis (MRA) is proposed and a multireolution finite element method is hence presented. The MRA framework is formulated out of a mutually nesting displacement subspace sequence. The MRA endows the proposed element with the resolution level (RL) to adjust the element node number, thus modulating structural analysis accuracy accordingly. As a result, the traditional 4-node rectangular Mindlin plate element and method is a mono-resolution one and also a special case of the proposed element and method. The meshing for the monoresolution plate element model is based on the empiricism while the RL adjusting for the multiresolution is laid on the rigorous mathematical basis. The accuracy of a structural analysis is actually determined by the RL, not by the mesh. The rational MRA enables the implementation of the multiresolution Mindlin plate element method to be more rational and efficient than that of the conventional monoresolution or o...
Analysis of Conforming and Nonconforming Quadrilateral Finite Element Methods for the
Sheen, Dongwoo
Analysis of Conforming and Nonconforming Quadrilateral Finite Element Methods for the Helmholtz in this analysis are the standard Q1 conforming finite element, the DSSY nonconforming element [5] and the P1-Santos-Sheen-Bennethum in [4]; also in the same paper a first rigorous finite element error analysis was carried out
A SpaceTime Finite Element Method for the Exterior Structural Acoustics Problem
Thompson, Lonny L.
A SpaceTime Finite Element Method for the Exterior Structural Acoustics Problem: Timediscontinuous Galerkin spacetime finite element method is formu lated for the exterior structural acoustics problem Introduction A spacetime finite element formulation is presented for solution of the exterior struc tural
Thompson, Lonny L.
L.L.Thompson: Finite element methods for acoustics, Preprint: J.Acoust.Soc.Am. A review of finite element methods for time-harmonic acoustics Lonny L. Thompson Department of Mechanical Engineering, Clemson University Clemson, South Carolina, 29634-0921, USA Email: lonny.thompson@ces.clemson.edu (Dated
A PIECEWISE LINEAR FINITE ELEMENT METHOD FOR THE BUCKLING AND THE VIBRATION PROBLEMS OF THIN
Rodríguez, Rodolfo
A PIECEWISE LINEAR FINITE ELEMENT METHOD FOR THE BUCKLING AND THE VIBRATION PROBLEMS OF THIN PLATES finite element method to approximate the buckling and the vibration problems of a thin plate. The method]). The method was applied to the plate vibration problem in [6] and [17, Section 7(b)], where it was proved
Paris-Sud XI, Université de
Analysis of the finite element heterogeneous multiscale method for nonlinear elliptic homogenization problems. Assyr Abdulle and Gilles Vilmart September 28, 2012 Abstract An analysis of the finite finite elements. Op- timal a-priori error estimates are obtained for the H1 and L2 norms, error bounds
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE H -FORMULATION OF TIME-DEPENDENT EDDY CURRENT
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE H - FORMULATION OF TIME-DEPENDENT EDDY CURRENT PROBLEMS, eddy current problem, adaptive finite element method, mul- tiply connected conductor, Team Workshop Problem 7 AMS subject classifications. 65M60, 65M50, 78A25 1. Introduction. Eddy currents appear in almost
Suo, Zhigang
A finite element method for transient analysis of concurrent large deformation and mass transport and Aerospace Engineering, Arizona State University, Tempe, Arizona 85287, USA 2 School of Engineering-dependent concurrent process of large deformation and mass transport is studied by developing a finite element method
A Space-Time Finite Element Method for the Exterior Acoustics Problem
Thompson, Lonny L.
A Space-Time Finite Element Method for the Exterior Acoustics Problem Lonny L. Thompson Department in exterior domains is discussed. The space-time formulation for the exterior acoustics problem is obtained, the development of a space-time finite element method for so- lution of the transient acoustics problem
A Space-Time Finite Element Method for the Exterior Structural Acoustics Problem
Thompson, Lonny L.
A Space-Time Finite Element Method for the Exterior Structural Acoustics Problem: Time-time finite element method is formu- lated for the exterior structural acoustics problem in two space formulation is presented for solution of the exterior struc- tural acoustics problem in two space dimensions
Bangerth, Wolfgang
Adaptive finite element methods for forward modeling in fluorescence enhanced frequency domain for Subsurface Modeling, ICES, University of Texas, Austin, TX Abstract: An adaptive finite element scheme the boundary measurements of photon energy resulting from the tissue stimulation via infrared light sources
Numerical Analysis of a Mixed Finite Element Method for a FlowTransport Problem
Chou, So-Hsiang
element method for the brine, radionuclides, and heat combined with a mixed finite element method dissolves to create a brine, radioactive elements decay to generate heat, and radionuclides are transported), the viscosity of the fluid is dependent on â?? c, the concentration of the brine in the fluid. Here and below
Unconstrained paving and plastering method for generating finite element meshes
Staten, Matthew L. (Albuquerque, NM); Owen, Steven J. (Albuquerque, NM); Blacker, Teddy D. (Albuquerque, NM); Kerr, Robert (Albuquerque, NM)
2010-03-02T23:59:59.000Z
Computer software for and a method of generating a conformal all quadrilateral or hexahedral mesh comprising selecting an object with unmeshed boundaries and performing the following while unmeshed voids are larger than twice a desired element size and unrecognizable as either a midpoint subdividable or pave-and-sweepable polyhedra: selecting a front to advance; based on sizes of fronts and angles with adjacent fronts, determining which adjacent fronts should be advanced with the selected front; advancing the fronts; detecting proximities with other nearby fronts; resolving any found proximities; forming quadrilaterals or unconstrained columns of hexahedra where two layers cross; and establishing hexahedral elements where three layers cross.
An implicit finite element method for discrete dynamic fracture
Jobie M. Gerken
1999-12-01T23:59:59.000Z
A method for modeling the discrete fracture of two-dimensional linear elastic structures with a distribution of small cracks subject to dynamic conditions has been developed. The foundation for this numerical model is a plane element formulated from the Hu-Washizu energy principle. The distribution of small cracks is incorporated into the numerical model by including a small crack at each element interface. The additional strain field in an element adjacent to this crack is treated as an externally applied strain field in the Hu-Washizu energy principle. The resulting stiffness matrix is that of a standard plane element. The resulting load vector is that of a standard plane element with an additional term that includes the externally applied strain field. Except for the crack strain field equations, all terms of the stiffness matrix and load vector are integrated symbolically in Maple V so that fully integrated plane stress and plane strain elements are constructed. The crack strain field equations are integrated numerically. The modeling of dynamic behavior of simple structures was demonstrated within acceptable engineering accuracy. In the model of axial and transverse vibration of a beam and the breathing mode of vibration of a thin ring, the dynamic characteristics were shown to be within expected limits. The models dominated by tensile forces (the axially loaded beam and the pressurized ring) were within 0.5% of the theoretical values while the shear dominated model (the transversely loaded beam) is within 5% of the calculated theoretical value. The constant strain field of the tensile problems can be modeled exactly by the numerical model. The numerical results should therefore, be exact. The discrepancies can be accounted for by errors in the calculation of frequency from the numerical results. The linear strain field of the transverse model must be modeled by a series of constant strain elements. This is an approximation to the true strain field, so some error is expected.
Lee, Sang Hoon
2012-02-14T23:59:59.000Z
, 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...
Harrison, Mark
1988-01-01T23:59:59.000Z
IMA Journal of Numerical Analysis (1988) 8, 415-433 Finite Element Methods for a Model for Full are given and then a discrete-time, explicit finite element procedure is defined and analysed, with finite on the existence, uniqueness and finite element approximation of the solution of Biot's equations were given in [15
A SYMMETRIC NODAL CONSERVATIVE FINITE ELEMENT METHOD FOR THE DARCY EQUATION
Mottram, Nigel
A SYMMETRIC NODAL CONSERVATIVE FINITE ELEMENT METHOD FOR THE DARCY EQUATION GABRIEL R. BARRENECHEA results. 1. Introduction The Darcy equation arising in a porous media field belongs to the family of mixed element methods [23, 21, 13, 9, 10] the range of possibilities to tackle the Darcy equation has increased
A SpaceTime Finite Element Method for the Exterior Acoustics Problem
Thompson, Lonny L.
A SpaceTime Finite Element Method for the Exterior Acoustics Problem by Lonny L. Thompson problem in exterior domains is discussed. The spacetime formulation for the exterior acoustics problem acoustics problem. i #12; Contents 1 Introduction 1 2 The Exterior Acoustics Problem 3 3 Spacetime finite
Mixed finite element methods for incompressible flow: Stationary ...
2010-04-14T23:59:59.000Z
May 14, 2009 ... Received 2 October 2008; accepted 27 January 2009 ... Thomas (RT) element of index k ? 0 and the velocity by piecewise .... We use the standard notations and definitions for the Sobolev spaces Hs( )d and Hs(? )d for.
RodrÃguez, Rodolfo
Numerical analysis of a finite element method for the axisymmetric eddy current model, 27002, Lugo, Spain The aim of this paper is to analyze a finite element method to solve an eddy current of the method are reported. Keywords: low-frequency harmonic Maxwell equations, eddy current problems, finite
Zornberg, Jorge G.
1391 1 INTRODUCTION An application of the finite element method (FEM) for non-linear elastoplastic, 2003; Oliveira, 2006). 2 FINITE ELEMENT REPRESENTATION OF REINFORCED SOIL A discrete representation, the reinforcement and the soil-reinforcement interface-- can be represented using a specific finite element with its
Uncoupled thermoelastic structural response by the finite element method
Linn, William Ray
1982-01-01T23:59:59.000Z
constant strain triangle (csT) element, when the solid mechanics problem is examined. Nonisothermal effects are obtained from the discretized form of equation (54), written as U . { {' [D] , {, { av - ? z f {*{ [Dj[BI {Q) dr (63) 2 J V V with 31 2 P... partial spacial derivatives and repeated indices imply summation), (k T ) P T[1+ 5( 1 & )( ? )] QT where (3X+2u) o T 6 6 v e (3) The style and citations of this thesis follow that of the 1 t'16166'1MttdJ~Eg where km is the thermal conductivity...
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS JUNQING for solving the eddy current model with voltage excitations for complicated three dimensional structures of the proposed method. Key words. Eddy current, circuit/field coupling, adaptivity, a posteriori error analysis
STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES Tayfun E boundaries and interfaces. The methods developed can be classified into two main categories: interface-tracking and interface-capturing techniques. Both classes of techniques are based on sta- bilized formulations
STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES of flow problems with moving boundaries and interfaces. The methods developed are categorized into two classes: interface-tracking and interface-capturing techniques. Both classes of techniques are based
A Finite Element Method for Fully Nonlinear and General Quasilinear Elliptic Problems
Pryer, Tristan
2011-01-01T23:59:59.000Z
We present a continuous finite element method for fully nonlinear elliptic equations. The tools we use are (1) a Newton linearisation, yielding a sequence of linear PDEs in nonvariational form and (2) the discretisation proposed in [LP11] allowing us to work directly on the strong form of a linear PDE. An added benefit to making use of this discretisation method is that a recovered (finite element) Hessian is a biproduct of the solution process. Benchmark numerical results illustrate the convergence properties of the scheme for some test problems.
Ng, Chi Kin
1978-01-01T23:59:59.000Z
DYNAMIC ANALYSIS OF SHELLS OF REVOLUTION SUBMERGED IN AN ACOUSTIC MEDIUM BY THE FINITE ELEMENT METHOD A Thesis by CHI KIN NG Submitted to the Graduate College of Texas AiIH University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE May 1978 Major Subject: Civil Engineering DYNAMIC ANALYSIS OF SHELLS OF REVOLUTION SUBMERGED IN AN ACOUSTIC MEDIUM BY THE FINITE ELEMENT METHOD A Thesis by CHI KIN NG Approved as to style and content by: Chf fC i'~t ( 8 ('i...
spectral stochastic finite-element methods for parametric ...
Mihai Anitescu
2006-11-30T23:59:59.000Z
Nov 30, 2006 ... Abstract: We present a method to approximate the solution mapping of ... Category 3: Applications -- Science and Engineering (Mechanical Engineering ) ... Mathematics and Computer Science Division, 9700 S Cass Avenue, ...
Gradient recovery in adaptive finite element methods for parabolic problems
Lakkis, Omar
2009-01-01T23:59:59.000Z
We derive energy-norm aposteriori error bounds, using gradient recovery (ZZ) estimators to control the spatial error, for fully discrete schemes for the linear heat equation. This appears to be the first completely rigorous derivation of ZZ estimators for fully discrete schemes for evolution problems, without any restrictive assumption on the timestep size. An essential tool for the analysis is the elliptic reconstruction technique. Our theoretical results are backed with extensive numerical experimentation aimed at (a) testing the practical sharpness and asymptotic behaviour of the error estimator against the error, and (b) deriving an adaptive method based on our estimators. An extra novelty provided is an implementation of a coarsening error "preindicator", with a complete implementation guide in ALBERTA.
Advanced finite-element methods for design and analysis of nanooptical structures: Applications
Burger, S; Pomplun, J; Blome, M; Schmidt, F; 10.1117/12.2001094
2013-01-01T23:59:59.000Z
An overview on recent applications of the finite-element method Maxwell-solver JCMsuite to simulation tasks in nanooptics is given. Numerical achievements in the fields of optical metamaterials, plasmonics, photonic crystal fibers, light emitting devices, solar cells, optical lithography, optical metrology, integrated optics, and photonic crystals are summarized.
Modeling Respiratory Lung Motion a Biophysical Approach using Finite Element Methods
Lübeck, Universität zu
Modeling Respiratory Lung Motion a Biophysical Approach using Finite Element Methods Rene Wernera motion gains in importance. In this paper a biophysical approach for modeling lung motion is described. Main aspects of the process of lung ventilation are identified and outlined as the starting point
Bangerth, Wolfgang
error estimates for adaptive mesh refinement to optimally model the strongly graded light distributionADAPTIVE FINITE ELEMENT METHODS FOR FLUORESCENCE ENHANCED FREQUENCY DOMAIN OPTICAL TOMOGRAPHY Modeling, ICES, University of Texas at Austin, TX ABSTRACT In this contribution we introduce adaptive
AN hp FINITE ELEMENT METHOD TO SOLVE A FLUID-SOLID VIBRATION PROBLEM
Rodríguez, Rodolfo
AN hp FINITE ELEMENT METHOD TO SOLVE A FLUID-SOLID VIBRATION PROBLEM CLAUDIO PADRA, RODOLFO RODR´IGUEZ , AND MARIO SCHEBLE § Abstract. This paper deals with a two-dimensional fluid-solid vibration problem arising from nuclear engineering: the vibration of elastically mounted tubes immersed in a cavity filled
Elgeti, Stefanie
2015-01-01T23:59:59.000Z
Fluid flow applications can involve a number of coupled problems. One is the simulation of free-surface flows, which require the solution of a free-boundary problem. Within this problem, the governing equations of fluid flow are coupled with a domain deformation approach. This work reviews five of those approaches: interface tracking using a boundary-conforming mesh and, in the interface capturing context, the level-set method, the volume-of-fluid method, particle methods, as well as the phase-field method. The history of each method is presented in combination with the most recent developments in the field. Particularly, the topics of extended finite elements (XFEM) and NURBS-based methods, such as Isogeometric Analysis (IGA), are addressed. For illustration purposes, two applications have been chosen: two-phase flow involving drops or bubbles and sloshing tanks. The challenges of these applications, such as the geometrically correct representation of the free surface or the incorporation of surface tension ...
Prediction of fluid flow in curved pipe using the finite element method
Maitin, Christopher Benjamin
1987-01-01T23:59:59.000Z
. Therefore mathematical models have been developed to simulate the elfect of these stresses on the flow field. Until recently these models have only been used for simple geometries. With the advancement of the computer, numerical methods have been de... OF SCIENCE May 1987 Major Subject: Mechanical Engineering PREDICTION OF FLUID FLOW IN CURVED PIPE USING THE FINITE ELEMENT METHOD A Thesis CHRISTOPHER B. MAITIN Approved as to style and content by: Dennis L. O'Neal (Chairman of Committee) Warren...
Recanati, Catherine
A finite element method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein Abstract Numerical computations of stationary states of fastrotating BoseEinstein condensates require rotation rates). Key words: Gross--Pitaevskii equation, finite element method, mesh adaptivity, BoseEinstein
Swaddiwudhipong, S; Liu, Z S
2012-01-01T23:59:59.000Z
Finite element method (FEM) suffers from a serious mesh distortion problem when used for high velocity impact analyses. The smooth particle hydrodynamics (SPH) method is appropriate for this class of problems involving severe damages but at considerable computational cost. It is beneficial if the latter is adopted only in severely distorted regions and FEM further away. The coupled smooth particle hydrodynamics - finite element method (SFM) has been adopted in a commercial hydrocode LS-DYNA to study the perforation of Weldox 460E steel and AA5083-H116 aluminum plates with varying thicknesses and various projectile nose geometries including blunt, conical and ogival noses. Effects of the SPH domain size and particle density are studied considering the friction effect between the projectile and the target materials. The simulated residual velocities and the ballistic limit velocities from the SFM agree well with the published experimental data. The study shows that SFM is able to emulate the same failure mechan...
Mixed-RKDG Finite Element Methods for the 2-D Hydrodynamic Model for Semiconductor Device Simulation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chen, Zhangxin; Cockburn, Bernardo; Jerome, Joseph W.; Shu, Chi-Wang
1995-01-01T23:59:59.000Z
In this paper we introduce a new method for numerically solving the equations of the hydrodynamic model for semiconductor devices in two space dimensions. The method combines a standard mixed finite element method, used to obtain directly an approximation to the electric field, with the so-called Runge-Kutta Discontinuous Galerkin (RKDG) method, originally devised for numerically solving multi-dimensional hyperbolic systems of conservation laws, which is applied here to the convective part of the equations. Numerical simulations showing the performance of the new method are displayed, and the results compared with those obtained by using Essentially Nonoscillatory (ENO) finite difference schemes. Frommore »the perspective of device modeling, these methods are robust, since they are capable of encompassing broad parameter ranges, including those for which shock formation is possible. The simulations presented here are for Gallium Arsenide at room temperature, but we have tested them much more generally with considerable success.« less
A study of arbitrary rotations of shells of revolution by the finite element method
Rosenbaum, James Byron
1974-01-01T23:59:59.000Z
. Haisler, Jr. Various nonlinear shell theories are reviewed, discussed, and one is selected for implementation into the solution code SNASOR III. The theory selected, Novozhilov's, is discussed in greater detail, comparing his nonlinear equations... to the ones in SNASOR III. The changes required to employ Novozhilov's nonlinear theory in SNASOR III are illustrated. The finite element method is then briefly discussed, nonlinear solution techniques are reviewed and the mod- ified incremental stiffness...
Kron`s reduction method applied to the time stepping finite element analysis of induction machines
Degeneff, R.C.; Gutierrez, M.R.; Salon, S.J.; Burow, D.W. [Rensselaer Polytechnic Inst., Troy, NY (United States). Electric Power Engineering Dept.] [Rensselaer Polytechnic Inst., Troy, NY (United States). Electric Power Engineering Dept.; Nevins, R.J. [Martin Marietta Corp., Schenectady, NY (United States)] [Martin Marietta Corp., Schenectady, NY (United States)
1995-12-01T23:59:59.000Z
The behavior of large induction motors during transient as well as steady state running conditions is of significant interest to the power industry. A variety of analytical predictive tools are employed to aid the design and predict their operation under transient and steady state conditions. One of the most powerful method for investigating the transient behavior of induction machines is a coupled time stepping finite element analysis which can combine electromagnetic fields, circuits and mechanical systems. Due to the complexity of the finite element induction machine model and the resulting large number of describing equations, the computation time required for such programs to solve practical problems becomes a major limitation. This becomes even more of a concern when different design options or operating scenarios are evaluated. This paper presents a strategy to reduce the required running time in order to make a parametric study of induction machines such as the assessment of different design options feasible. This is accomplished by reducing the number of finite element equations that must be solved while maintaining the same level of accuracy of solutions. This method is based on Kron`s network reduction work for linear systems and has successfully been applied to large lumped parameter model of transformers. This paper illustrates the reduction method by comparing the flux density in the air gap for a complete FEM model of an induction machine to that of the reduced model. The results are essentially identical with a reduction in computational time of approximately 71%.
Gao, Kai; Gibson, Richard L; Chung, Eric T; Efendiev, Yalchin
2014-01-01T23:59:59.000Z
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both boundaries and the interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale medium property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and di...
An h-adaptive finite element method for turbulent heat transfer
Carriington, David B [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
A two-equation turbulence closure model (k-{omega}) using an h-adaptive grid technique and finite element method (FEM) has been developed to simulate low Mach flow and heat transfer. These flows are applicable to many flows in engineering and environmental sciences. Of particular interest in the engineering modeling areas are: combustion, solidification, and heat exchanger design. Flows for indoor air quality modeling and atmospheric pollution transport are typical types of environmental flows modeled with this method. The numerical method is based on a hybrid finite element model using an equal-order projection process. The model includes thermal and species transport, localized mesh refinement (h-adaptive) and Petrov-Galerkin weighting for the stabilizing the advection. This work develops the continuum model of a two-equation turbulence closure method. The fractional step solution method is stated along with the h-adaptive grid method (Carrington and Pepper, 2002). Solutions are presented for 2d flow over a backward-facing step.
Torres-Verdín, Carlos
Simulation of borehole-eccentered triaxial induction measurements using a Fourier hp finite-element with a 2D, goal-oriented, high-order, and self- adaptive hp finite-element refinement strategy three mutually orthogonal transmitter coils located at the same vertical position and three collocated
Pontaza, Juan Pablo
2004-09-30T23:59:59.000Z
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 ...
Felice, Maria V. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom and Rolls-Royce plc., Bristol BS34 7QE (United Kingdom); Velichko, Alexander; Wilcox, Paul D. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Barden, Tim J.; Dunhill, Tony K. [Rolls-Royce plc., Bristol BS34 7QE (United Kingdom)
2014-02-18T23:59:59.000Z
A hybrid model to simulate the ultrasonic array response from stress corrosion cracks is presented. These cracks are branched and difficult to detect so the model is required to enable optimization of an array design. An efficient frequency-domain finite element method is described and selected to simulate the ultrasonic scattering. Experimental validation results are presented, followed by an example of the simulated ultrasonic array response from a real stress corrosion crack whose geometry is obtained from an X-ray Computed Tomography image. A simulation-assisted array design methodology, which includes the model and use of real crack geometries, is proposed.
Higher-order adaptive finite-element methods for Kohn–Sham density functional theory
Motamarri, P. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Nowak, M.R. [Department of Electrical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Electrical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Leiter, K.; Knap, J. [U.S. Army Research Labs, Aberdeen Proving Ground, Aberdeen, MD 21001 (United States)] [U.S. Army Research Labs, Aberdeen Proving Ground, Aberdeen, MD 21001 (United States); Gavini, V., E-mail: vikramg@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)
2013-11-15T23:59:59.000Z
We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of Kohn–Sham density-functional theory (DFT). To this end, we develop an a priori mesh-adaption technique to construct a close to optimal finite-element discretization of the problem. We further propose an efficient solution strategy for solving the discrete eigenvalue problem by using spectral finite-elements in conjunction with Gauss–Lobatto quadrature, and a Chebyshev acceleration technique for computing the occupied eigenspace. The proposed approach has been observed to provide a staggering 100–200-fold computational advantage over the solution of a generalized eigenvalue problem. Using the proposed solution procedure, we investigate the computational efficiency afforded by higher-order finite-element discretizations of the Kohn–Sham DFT problem. Our studies suggest that staggering computational savings—of the order of 1000-fold—relative to linear finite-elements can be realized, for both all-electron and local pseudopotential calculations, by using higher-order finite-element discretizations. On all the benchmark systems studied, we observe diminishing returns in computational savings beyond the sixth-order for accuracies commensurate with chemical accuracy, suggesting that the hexic spectral-element may be an optimal choice for the finite-element discretization of the Kohn–Sham DFT problem. A comparative study of the computational efficiency of the proposed higher-order finite-element discretizations suggests that the performance of finite-element basis is competing with the plane-wave discretization for non-periodic local pseudopotential calculations, and compares to the Gaussian basis for all-electron calculations to within an order of magnitude. Further, we demonstrate the capability of the proposed approach to compute the electronic structure of a metallic system containing 1688 atoms using modest computational resources, and good scalability of the present implementation up to 192 processors.
Medial Techniques for Automating Finite Element Analysis
Whitton, Mary C.
Medial Techniques for Automating Finite Element Analysis by Jessica Renee Crawford Crouch Analysis. (Under the direction of Stephen M. Pizer.) Finite element analysis provides a principled method the simulation of tissue deformation. The drawback to using finite element analysis for imaging problems
Finite Element Analysis in Vertebrate Biomechanics
Finite Element Analysis in Vertebrate Biomechanics CALLUM F. ROSS* Department of Organismal Biology presents a series of papers that apply the method of finite element analysis (FEA) to questions ontogenetic or phylogenetic transformations. © 2005 Wiley-Liss, Inc. Key words: finite-element analysis
Probabilistic finite element analysis of marine risers
Leder, H. Vern
1990-01-01T23:59:59.000Z
ILLUSTRATIVE EXAMPLE. . . . . . . . . . . . . . . . . . 4 APPLICATION OF PROBABILISTIC FINITE ELEMENT METHODS TO MARINE RISER ANALYSES 4. 1 Finite Element Model . 4. 1. 1 Formulation of the Equation of Motion 4. 1. 2 Finite Element Discretization 4. 1. 3... Development of the Mass and Stiffness Matrices 4. 1. 4 Development of the Damping Matrix 4. 1. 5 Development of the Force Vector 28 38 41 41 44 48 48 vn 4. 1. 6 Solution to the Finite Element Equations 4. 2 Applications of Response Predictions 4...
A stabilized mixed finite element method for Darcy flow Arif Masud a,*, Thomas J.R. Hughes b
Masud, Arif
, advectivediffusive equations for concentrations are coupled to the Darcy flow equation. For examplesA stabilized mixed finite element method for Darcy flow Arif Masud a,*, Thomas J.R. Hughes b element methods for Darcy flow. Stability and an a priori error estimate in the ``stability norm
Chen, Lingfeng, M. Eng. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
Common finite element programs for plate bending analysis are complicated and limited by the common plate theories. Such programs are usually not user-friendly for designers to implement. Lately, Hou Man et al. from the ...
Liu, Xuchen
2015-05-04T23:59:59.000Z
surrounded by soft tissues, 2) a layered ring model representing an arterial wall cross-section. The hypothetical "measured" displacement field for these problem domains will be created by solving the finite element forward problem. Additionally, noise...
Probabilistic finite element analysis of a craniofacial finite element model Michael A. Berthaume a s t r a c t We employed a probabilistic finite element analysis (FEA) method to determine how 2011 Accepted 18 January 2012 Available online 27 January 2012 Keywords: Probabilistic analysis Finite
Zingan, Valentin Nikolaevich
2012-07-16T23:59:59.000Z
Galerkin DoF degree of freedom ENO essentially non-oscillatory EoS equation of state FE finite element FEM finite element method FVM finite volume method IBVP initial boundary value problem IVP initial value problem JLG Jean-Luc Guermond KPP..., the influence of diffusion, friction, and thermal conduction is limited to a very thin region adjacent to a body surface, a so-called boundary layer, and the remainder of the flow outside this region is essentially inviscid. For flows over slender bodies...
Modeling a bender element test using Abaqus Finite Element Program
Johnson, Sean (Sean Michael)
2011-01-01T23:59:59.000Z
Finite Element Methods hold promise for modeling the behavior of an unsaturated soil specimen subjected to bender element agitation. The immediate objective of this research project is to reproduce a bender element test ...
Comparison of methods for solving nonlinear finite-element equations in heat transfer
Cort, G.E.; Graham, A.L.; Johnson, N.L.
1981-01-01T23:59:59.000Z
We have derived two new techniques for solving the finite-element heat-transfer equations with highly nonlinear boundary conditions and material properties. When compared with the more commonly employed successive substitution and Newton-Raphson procedures, the new methods speed convergence rates and simultaneously increase the radius of convergence. We have observed reductions in computation time in excess of 80% when the new techniques are employed. The first method accelerates the standard Newton-Raphson approach when the degree of the nonlinearity is known (for example, radiation boundary conditions or a prescribed temperature dependence in the thermal conductivity). The second technique employs feedback to regulate the solution algorithm during execution. Comparisons of these techniques are given for several practical examples.
A Generalized Multiscale Finite Element Method for Poroelasticity Problems I: Linear Problems
Brown, Donald L
2015-01-01T23:59:59.000Z
In this paper, we consider the numerical solution of poroelasticity problems that are of Biot type and develop a general algorithm for solving coupled systems. We discuss the challenges associated with mechanics and flow problems in heterogeneous media. The two primary issues being the multiscale nature of the media and the solutions of the fluid and mechanics variables traditionally developed with separate grids and methods. For the numerical solution we develop and implement a Generalized Multiscale Finite Element Method (GMsFEM) that solves problem on a coarse grid by constructing local multiscale basis functions. The procedure begins with construction of multiscale bases for both displacement and pressure in each coarse block. Using a snapshot space and local spectral problems, we construct a basis of reduced dimension. Finally, after multiplying by a multiscale partitions of unity, the multiscale basis is constructed in the offline phase and the coarse grid problem then can be solved for arbitrary forcin...
Finite Element Analysis Skateboard Truck
De, Suvranu
Finite Element Analysis Of a Skateboard Truck #12;2 Executive Summary: Engineering is and always is an element of the `truck,' which holds the wheels. Finite Element analysis will be conducted on this piece a combination of SolidWorks (for modeling) and ABAQUS (for finite element analysis). It is evident from
Local Jacobi Operators and Applications to the p-version of Finite Element Method in Two Dimensions
Guo, Benqi
Local Jacobi Operators and Applications to the p-version of Finite Element Method in Two Dimensions Benqi Guo Ivo Babuska Abstract Based on Jacobi projection operators p, on elements and edges we have designed local Jacobi operators j for smooth and singular solution on each triangular and quadrilateral
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-04-14T23:59:59.000Z
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale mediummore »property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.« less
ECI 212A: Finite Element Procedures in Applied Mechanics
Schladow, S. Geoffrey
), "The Finite Element Method: Linear Static and Dynamic Finite Element Analysis," Prentice), "Concepts and Appli- cations of Finite Element Analysis," 4th Ed., John Wiley and Sons, NY. 5. M. S, Philadelphia, PA. 6. G. Strang and G. J. Fix (1973), "An Analysis of the Finite Element Method," Prentice
Finite element methods for 3D eddy current prob-lems in bounded domains subject to realistic
RodrÃguez, Rodolfo
Finite element methods for 3D eddy current prob- lems in bounded domains subject to realistic techniques to approximate eddy current prob- lems. The focus of the article is on the analysis of weak]), magnetostatics ([59, 60, 80, 81, 109, 110, 114]), eddy current ([1, 2, 3, 6, 7, 8, 9, 19, 20, 21, 23, 24, 25, 26
Zabaras, Nicholas J.
A STABILIZED VOLUME-AVERAGING FINITE ELEMENT METHOD FOR FLOW IN POROUS MEDIA AND BINARY ALLOY of Mechanical and Aerospace Engineering 188 Frank H. T. Rhodes Hall Cornell University Ithaca, NY 14853 algorithm is presented for the analysis of flow in porous media and in the solidification of binary alloys
Tezduyar, Tayfun E.
Chapter 17 in Encyclopedia of Computational Mechanics, Volume 3: Fluids Finite Element Methods surfaces, two-fluid interfaces, fluidobject and fluidstructure in- teractions, and moving mechanical in Encyclopedia of Computational Mechanics, Volume 3: Fluids (eds. E. Stein, R. De Borst and T.J.R. Hughes), John
Masud, Arif
. There are many processes in nat- ure that can be modeled using the Darcy flow equations. Oil extraction to be solenoidal (i.e., a divergence free vector field). The main issue is that the equations of Darcy flow leadA stabilized mixed finite element method for Darcy flow based on a multiscale decomposition
Full wave simulation of waves in ECRIS plasmas based on the finite element method
Torrisi, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania, Italy and Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell'Informazione, delle Infrastrutture e dell'Energia Sostenibile (DIIES), Via Graziella, I (Italy); Mascali, D.; Neri, L.; Castro, G.; Patti, G.; Celona, L.; Gammino, S.; Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania (Italy); Di Donato, L. [Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica (DIEEI), Viale Andrea Doria 6, 95125 Catania (Italy); Sorbello, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123, Catania, Italy and Università degli Studi di Catania, Dipartimento di Ingegneria Elettrica Elettronica ed Informatica (DIEEI), Viale Andrea Doria 6, 95125 Catania (Italy); Isernia, T. [Università Mediterranea di Reggio Calabria, Dipartimento di Ingegneria dell'Informazione, delle Infrastrutture e dell'Energia Sostenibile (DIIES), Via Graziella, I-89100 Reggio Calabria (Italy)
2014-02-12T23:59:59.000Z
This paper describes the modeling and the full wave numerical simulation of electromagnetic waves propagation and absorption in an anisotropic magnetized plasma filling the resonant cavity of an electron cyclotron resonance ion source (ECRIS). The model assumes inhomogeneous, dispersive and tensorial constitutive relations. Maxwell's equations are solved by the finite element method (FEM), using the COMSOL Multiphysics{sup ®} suite. All the relevant details have been considered in the model, including the non uniform external magnetostatic field used for plasma confinement, the local electron density profile resulting in the full-3D non uniform magnetized plasma complex dielectric tensor. The more accurate plasma simulations clearly show the importance of cavity effect on wave propagation and the effects of a resonant surface. These studies are the pillars for an improved ECRIS plasma modeling, that is mandatory to optimize the ion source output (beam intensity distribution and charge state, especially). Any new project concerning the advanced ECRIS design will take benefit by an adequate modeling of self-consistent wave absorption simulations.
Finite Element Analysis of the Schroedinger Equation
Avtar S. Sehra
2007-04-17T23:59:59.000Z
The purpose of this work is to test the application of the finite element method to quantum mechanical problems, in particular for solving the Schroedinger equation. We begin with an overview of quantum mechanics, and standard numerical techniques. We then give an introduction to finite element analysis using the diffusion equation as an example. Three numerical time evolution methods are considered: the (tried and tested) Crank-Nicolson method, the continuous space-time method, and the discontinuous space-time method.
Jegbefume, E.U.
1981-01-01T23:59:59.000Z
The plane strain two-dimensional finite element model employing the method of negative reaction loading was used to model roof collapse and subsidence that result from underground coal gasification. Subsidence results from a preliminary finite element model were compared with those from a theoretical model having identical assumptions. The finite element model was extended to include dry zones of rock around the cavity resulting from the underground gasification. The model was further extended to include thermal loading, thermal softening and roof collapse. Roof collapse initiation and growth were modelled by examining the portion of the roof immediately above the cavity. A creep program utilizing the method incremental strains was developed and run in conjunction with the Pafec 70 + program. The overburden rock was treated as a linear viscoelastic material having deformation parameters of the generalized Kelvin model. Finally, the finite element model was used to carry out a case history study of subsidence and roof collapse of an underground gasification field experiment in Wyoming.
Scalability Analysis of Partitioning Strategies for Finite Element Graphs. \\Lambda
Kumar, Vipin
Scalability Analysis of Partitioning Strategies for Finite Element Graphs. \\Lambda Grama Y. Ananth Y. Grama ananth@cs:umn:edu Abstract Issues of partitioning Finite Element Graphs are central for implementing the Finite Element Method (FEM). Parallel formulations of finite element techniques require
DOLFIN: Automated Finite Element Computing
Logg, Anders; Wells, G N
2009-01-01T23:59:59.000Z
´de´lec 1980]. (4) L2-conforming finite elements: (a) DGq, arbitrary degree discontinuous Lagrange elements; and (b) CR1, first degree Crouzeix–Raviart5 elements [Crouzeix and Raviart 1973]. Arbitrary combinations of the above elements may be used to define...
Analysis of an interface stabilised finite element method: The advection-diffusion-reaction equation
Wells, G N
2009-10-29T23:59:59.000Z
is denoted by ?0. Adjacent cells are considered to share a common facet F . The bilinear and linear forms for the advection-diffusion-reaction equation are now introduced. Using the notation w = (w, w¯) and v = (v, v¯), consider the bilinear form: B (w... ? h , the finite element problem of interest reads: find uh ?W ?h such that B (uh,vh) = L (vh) ?vh ?W ?h . (2.8) Noteworthy in the bilinear form is that the functions wh, which are discontinuous across cell facets, are not linked directly across facets...
electroseismic monitoring of co2 sequestration: a finite element ...
Fabio Zyserman
Keywords: Electroseismic Modeling, Poroelasticity, CO2 sequestration, Finite element methods. 2000 AMS ... carbon dioxide emissisons into the atmosphere.
X. Frank Xu
2010-03-30T23:59:59.000Z
Multiscale modeling of stochastic systems, or uncertainty quantization of multiscale modeling is becoming an emerging research frontier, with rapidly growing engineering applications in nanotechnology, biotechnology, advanced materials, and geo-systems, etc. While tremendous efforts have been devoted to either stochastic methods or multiscale methods, little combined work had been done on integration of multiscale and stochastic methods, and there was no method formally available to tackle multiscale problems involving uncertainties. By developing an innovative Multiscale Stochastic Finite Element Method (MSFEM), this research has made a ground-breaking contribution to the emerging field of Multiscale Stochastic Modeling (MSM) (Fig 1). The theory of MSFEM basically decomposes a boundary value problem of random microstructure into a slow scale deterministic problem and a fast scale stochastic one. The slow scale problem corresponds to common engineering modeling practices where fine-scale microstructure is approximated by certain effective constitutive constants, which can be solved by using standard numerical solvers. The fast scale problem evaluates fluctuations of local quantities due to random microstructure, which is important for scale-coupling systems and particularly those involving failure mechanisms. The Green-function-based fast-scale solver developed in this research overcomes the curse-of-dimensionality commonly met in conventional approaches, by proposing a random field-based orthogonal expansion approach. The MSFEM formulated in this project paves the way to deliver the first computational tool/software on uncertainty quantification of multiscale systems. The applications of MSFEM on engineering problems will directly enhance our modeling capability on materials science (composite materials, nanostructures), geophysics (porous media, earthquake), biological systems (biological tissues, bones, protein folding). Continuous development of MSFEM will further contribute to the establishment of Multiscale Stochastic Modeling strategy, and thereby potentially to bring paradigm-shifting changes to simulation and modeling of complex systems cutting across multidisciplinary fields.
Finite Element Analysis in Functional BRIAN G. RICHMOND,1
Finite Element Analysis in Functional Morphology BRIAN G. RICHMOND,1 * BARTH W. WRIGHT,1 IAN GROSSE element analysis. © 2005 Wiley-Liss, Inc. Key words: finite-element analysis; mastication; primates; biome This article reviews the fundamental principles of the finite element method and the three basic steps (model
Flexible finite-element modeling of global geomagnetic depth sounding
Ribaudo, Joseph Thomas
2011-01-01T23:59:59.000Z
OF CALIFORNIA, SAN DIEGO Flexible Finite-Element Modeling ofOF THE DISSERTATION Flexible Finite-Element Modeling ofin Chapter 2. The method is flexible enough to allow for a
k - Version of Finite Element Method for Polymer flows using Giesekus Constitutive Model
Deshpande, Kedar M.
2008-01-31T23:59:59.000Z
= Velocity in x direction v = Dimensionless Velocity in x direction ??xx = Normal Stress in x direction ?xx = Dimensionless Normal Stress in x direction ??yy = Normal Stress in y direction ?yy = Dimensionless Normal Stress in y direction ??xy = Shear Stress... of Pressure p over an element primeeprime ?hxx = Interpolation of normal stress ?xx over an element primeeprime ?hyy = Interpolation of normal stress ?yy over an element primeeprime ?hxy = Interpolation of shear stress ?xy over an element primeeprime ??p...
Zingan, Valentin Nikolaevich
2012-07-16T23:59:59.000Z
This work develops a discontinuous Galerkin finite element discretization of non- linear hyperbolic conservation equations with efficient and robust high order stabilization built on an entropy-based artificial viscosity approximation...
Ernest Valeo, Jay R. Johnson, Eun-Hwa and Cynthia Phillips
2012-03-13T23:59:59.000Z
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.
Yu, Guangbin [The Higher Educational Key Laboratory for Measuring and Control Technology and Instrumentations of Heilongjiang Province, Harbin University of Science and Technology, Harbin 150080 (China); Tang, Chaolong [Department of Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), University of Alabama, Tuscaloosa, Alabama 35487 (United States); Song, Jinhui, E-mail: jhsong@eng.ua.edu, E-mail: wqlu@cigit.ac.cn [The Higher Educational Key Laboratory for Measuring and Control Technology and Instrumentations of Heilongjiang Province, Harbin University of Science and Technology, Harbin 150080 (China); Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China); Department of Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), University of Alabama, Tuscaloosa, Alabama 35487 (United States); Lu, Wenqiang, E-mail: jhsong@eng.ua.edu, E-mail: wqlu@cigit.ac.cn [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China)
2014-04-14T23:59:59.000Z
Based on conductivity characterization of single crystal zinc oxide (ZnO) micro/nanobelt (MB/NB), we further investigate the physical mechanism of nonlinear intrinsic resistance-length characteristic using finite element method. By taking the same parameters used in experiment, a model of nonlinear anisotropic resistance change with single crystal MB/NB has been deduced, which matched the experiment characterization well. The nonlinear resistance-length comes from the different electron moving speed in various crystal planes. As the direct outcome, crystallography of the anisotropic semiconducting MB/NB has been identified, which could serve as a simple but effective method to identify crystal growth direction of single crystal semiconducting or conductive nanomaterial.
Blacker, Teddy D. (12205 Kashmir, N.E., Albuquerque, NM 87111)
1994-01-01T23:59:59.000Z
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.
Shahri, Mehdi Abbaszadeh
2006-04-12T23:59:59.000Z
) to investigate the stress fields around and inside the cement, and to forecast the time of failure and its affect on cement integrity. This method is more powerful than conventional stability methods since complex boundary conditions are involved as initial...
A study of arbitrary rotations of shells of revolution by the finite element method
Rosenbaum, James Byron
1974-01-01T23:59:59.000Z
were reduced to eiskf3, ez3kz~, and the squares and products of the two. This contributed rotation effects to the nonlinear strain energy which previously had not been taken into account. As a computational time saver, the partial derivatives... II-1 III-1 IV-1 Geometry of Shell of Revolution Segment. . Coordinization of Shell Element. . Comparison of SNASOR III with New SNASOR III for a Shallow Shell of X = 6. Page 14 26 31 IV-2 Buckling Analysis of Higher Order Strain Energy...
Rieben, R N
2004-07-20T23:59:59.000Z
The goal of this dissertation is twofold. The first part concerns the development of a numerical method for solving Maxwell's equations on unstructured hexahedral grids that employs both high order spatial and high order temporal discretizations. The second part involves the use of this method as a computational tool to perform high fidelity simulations of various electromagnetic devices such as optical transmission lines and photonic crystal structures to yield a level of accuracy that has previously been computationally cost prohibitive. This work is based on the initial research of Daniel White who developed a provably stable, charge and energy conserving method for solving Maxwell's equations in the time domain that is second order accurate in both space and time. The research presented here has involved the generalization of this procedure to higher order methods. High order methods are capable of yielding far more accurate numerical results for certain problems when compared to corresponding h-refined first order methods , and often times at a significant reduction in total computational cost. The first half of this dissertation presents the method as well as the necessary mathematics required for its derivation. The second half addresses the implementation of the method in a parallel computational environment, its validation using benchmark problems, and finally its use in large scale numerical simulations of electromagnetic transmission devices.
Hybrid asymptotic-finite element method for stiff two-point boundary value problems
Chin, R.C.Y.; Krasny, R.
1983-06-01T23:59:59.000Z
An accurate and efficient numerical method has been developed for a nonlinear stiff second order two-point boundary value problem. The scheme combines asymptotic methods with the usual solution techniques for two-point boundary value problems. A new modification of Newton's method or quasilinearization is used to reduce the nonlinear problem to a sequence of linear problems. The resultant linear problem is solved by patching local solutions at the knots or equivalently by projecting onto an affine subset constructed from asymptotic expansions. In this way, boundary layers are naturally incorporated into the approximation. An adaptive mesh is employed to achieve an error of O(1/N/sup 2/) + O(..sqrt..e). Here, N is the number of intervals and epsilon << 1 is the singular perturbation parameter. Numerical computations are presented.
Suresh, Krishnan
Submitted to: Finite Elements in Analysis and Design 1 Finite Element Analysis over Tangled In modern finite element analysis (FEA), a mesh is said to be `tangled' if it contains one or more inverted are also illustrated. 1. INTRODUCTION In modern finite element analysis (FEA), the underlying mesh
A TWODIMENSIONAL MOVING FINITE ELEMENT METHOD WITH LOCAL REFINEMENT BASED ON A POSTERIORI ERROR
Cao, Weiming
and Flaherty [1] to the twodimensional case, where clusters of mesh points are built up and moved (middle), and rhrefinement with N = 541 yields e L2() = 1.57E-2 (right). While the rmethod wastes too
A stabilized stochastic finite element second-order projection method for modeling
Zabaras, Nicholas J.
of freedom. Because of the porosity dependence of the pressure gradient term in the governing flow equations-order projection method is presented based on a pressure gradient projection. A two- dimensional stochastic problem occurring in var- ious applications such as fluidized beds, solidification of alloys, geothermal energy
Bailey, Teresa S
2008-10-10T23:59:59.000Z
) applied to the particle transport equation in two-dimensional cylindrical (RZ) and three-dimensional Cartesian (XYZ) geometries. We have designed this method to be applicable to radiative-transfer problems in radiation-hydrodynamics systems... ..................................................................... 7 II AN INTRODUCTION TO RADIATION HYDRODYNAMICS....... 10 The Euler equations........................................................................ 10 The radiative transfer equations...
A 3D finite element method for flexible multibody Johannes Gerstmayr, Joachim Schoberl
Schoeberl, Joachim
-Kutta scheme. The present method has been imple- mented and tested with the FE-package NETGEN/NGSOLVE. Keywords dynamics, e.g. for the investigation of a slider-crank mechanism [9], the stability of a rotor-blade of a helicopter or the stability of a satellite with highly flexible solar panels, see Bremer [5]. While most
DOLFIN: Automated finite element computing
Logg, Anders; Wells, G N
2009-02-25T23:59:59.000Z
, and in particular the C++ Technical Report 1 (TR1) std::tr1::shared ptr and Boost boost:shared ptr (DOLFIN currently uses boost:shared ptr since this is better supported by SWIG than is std::tr1::shared ptr). In managing data sharing, this solution has reduced... . DOLFIN: Automated Finite Element Computing · 7 3. DESIGN CONSIDERATIONS The successful development of DOLFIN has been driven by two keys factors. The first is striving for technical innovation. Examples of this include the use of a form compiler...
Griffith, Daniel Todd; Segalman, Daniel Joseph
2006-10-01T23:59:59.000Z
A technique published in SAND Report 2006-1789 ''Model Reduction of Systems with Localized Nonlinearities'' is illustrated in two problems of finite element structural dynamics. That technique, called here the Method of Locally Discontinuous Basis Vectors (LDBV), was devised to address the peculiar difficulties of model reduction of systems having spatially localized nonlinearities. It's illustration here is on two problems of different geometric and dynamic complexity, but each containing localized interface nonlinearities represented by constitutive models for bolted joint behavior. As illustrated on simple problems in the earlier SAND report, the LDBV Method not only affords reduction in size of the nonlinear systems of equations that must be solved, but it also facilitates the use of much larger time steps on problems of joint macro-slip than would be possible otherwise. These benefits are more dramatic for the larger problems illustrated here. The work of both the original SAND report and this one were funded by the LDRD program at Sandia National Laboratories.
Time finite element methods for large rotational dynamics of multibody systems
Mello, F.J.; Borri, M.; Atluri, S.N. (Georgia Inst. of Tech., Atlanta, GA (USA). Center for Computational Mechanics)
1990-01-01T23:59:59.000Z
Weak formulations in Analytical Dynamics are developed, paralleling the variational methods in elastostatics, and including a fundamental yet novel approach for treating constraints (both holonomic and nonholonomic). A general three field approach is presented, in which the momentum balance conditions, the compatibility conditions between displacement and velocity, the constitutive relations and the displacement and momentum boundary conditions are all enforced in weak form. A primal, or kinematic formulation is developed from the general form by enforcing the compatibility conditions and displacement boundary conditions a priori. The conditional stability of the kinematic formulation is the counterpart of the locking phenomenon in elastostatics and may be avoided, either by reduced order integration, or by utilizing a mixed formulation. Toward this end, a two field mixed formulation is presented, which follows from the general form, when the constitutive relations are satisfied a priori. A general set of the constraint equations are introduced into the kinematic and mixed formulations, using a specific choice of multipliers, which results in modified variational principles. Several simple examples concerning rigid body dynamics are presented. 15 refs., 18 figs.
Student Award Competition Finite Element EEG and MEG Simulations for Realistic Head Models
Zhukov, Leonid
than would be possible using linear elements alone. [1] D.S. Burnett. Finite Element Analysis: FromStudent Award Competition Finite Element EEG and MEG Simulations for Realistic Head Models be approximated by a technique such as the finite element method [1]. Most applications of the finite element
Frey, Pascal
Uzawa conjugate gradient method for the Stokes problem: Matlab implementation with P1-iso-P2/P1 implementation of the Uzawa Conjugate gradient algorithm for the generalized Stokes problem with a P1-iso-P2/P1 for the generalized Stokes problem using the P1-iso-P2/P1 finite element. The Uzawa scheme is a decomposition
Construction of Higher Order Finite Element with
Kern, Michel
' & $ % Construction of Higher Order Finite Element with Mass Lumping Using Computer Algebra. (3D, combinatorial analysis, new third order element) 2 #12; ' & $ % Guidelines for the construction of nodes must be ~ P k unisolvent. 2. Finite element must be continuous. 3. Quadrature formula must satisfy
Williams, P.T.
1993-09-01T23:59:59.000Z
As the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This dissertation asserts that one key to accomplishing this goal is recognition of the dual role assumed by the pressure, i.e., a mechanism for instantaneously enforcing conservation of mass and a force in the mechanical balance law for conservation of momentum. Proving this assertion has motivated the development of a new, primitive-variable, incompressible, CFD algorithm called the Continuity Constraint Method (CCM). The theoretical basis for the CCM consists of a finite-element spatial semi-discretization of a Galerkin weak statement, equal-order interpolation for all state-variables, a 0-implicit time-integration scheme, and a quasi-Newton iterative procedure extended by a Taylor Weak Statement (TWS) formulation for dispersion error control. Original contributions to algorithmic theory include: (a) formulation of the unsteady evolution of the divergence error, (b) investigation of the role of non-smoothness in the discretized continuity-constraint function, (c) development of a uniformly H{sup 1} Galerkin weak statement for the Reynolds-averaged Navier-Stokes pressure Poisson equation, (d) derivation of physically and numerically well-posed boundary conditions, and (e) investigation of sparse data structures and iterative methods for solving the matrix algebra statements generated by the algorithm.
A PROBABILISTIC FINITE ELEMENT ANALYSIS OF RESIDUAL STRESS FORMATION
Grujicic, Mica
A PROBABILISTIC FINITE ELEMENT ANALYSIS OF RESIDUAL STRESS FORMATION IN SHRINK-FIT CERAMIC shrink fitting of the jacket over the lining is studied using a probabilistic finite element analysis structural analysis approach, known as the Advanced Mean Value (AMV) method, is used which enables
Blank optimization in sheet metal forming using finite element simulation
Goel, Amit
2006-04-12T23:59:59.000Z
and the friction between the blank and punch/die. In this research, a new method for optimum blank shape design using finite element analysis has been proposed. Explicit non-linear finite element (FE) code LSDYNA is used to simulate the deep drawing process. FE...
Plane-wave fluorescence tomography with adaptive finite elements
Bangerth, Wolfgang
Plane-wave fluorescence tomography with adaptive finite elements Amit Joshi Photon Migration reflectance imaging setup. The method employs planar illumination with modulated light and frequency domain fluo- rescence measurements made on the illumination plane. An adaptive finite-element algorithm
Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01T23:59:59.000Z
Vijayaraghavan, A. (2005), “Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool” ABSTRACT DEFORM-
Probabilistic slope stability analysis by finite elements D.V. Griffiths*
Probabilistic slope stability analysis by finite elements D.V. Griffiths* and Gordon A. Fenton. The advanced method, called the random finite element method (RFEM), uses elasto- plasticity combined nonlinear finite element methods are combined with ran- dom field generation techniques. This method, called
A piecewise linear finite element discretization of the diffusion equation
Bailey, Teresa S
2006-10-30T23:59:59.000Z
In this thesis, we discuss the development, implementation and testing of a piecewise linear (PWL) continuous Galerkin finite element method applied to the threedimensional diffusion equation. This discretization is particularly interesting because...
Benchmarking of finite element codes for radioactive material transportation packages
Ammerman, D.J.
1996-10-01T23:59:59.000Z
The increased power of computers and computer codes makes the use of nonlinear dynamic finite element analyses attractive for use as a tool used in the design and certification of radioactive material transportation packages. For this analysis technique to be acceptable it must be demonstrated. The technique has the ability to accurately capture the response of the packages to accident environments required by the regulations. The best method of demonstrating this ability is via a series of benchmark analyses. In this paper three benchmark problems involving significant inelastic deformations will be discussed. One of the problems has been analyzed using many different finite element codes. The other two problems involve comparison of finite element calculations to the results form physical tests. The ability of the finite element method to accurately capture the response in these three problems indicates the method should be acceptable for radioactive material transportation package design and certification.
Optimal convergence analysis for the eXtended Finite Element Serge Nicaise 1
Paris-Sud XI, Université de
Optimal convergence analysis for the eXtended Finite Element Method Serge Nicaise 1 , Yves Renard 2Xtended Finite Element Method (Xfem), namely the Xfem with a cut-off function and the stan- dard Xfem finite element method, error estimates, stress intensity factors. 1 Introduction Inspired by the Pufem
Finite element analysis of multilayer coextrusion.
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
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.
2.094 Finite Element Analysis of Solids and Fluids, Spring 2008
Kim, Do-Nyun
This course presents finite element theory and methods for general linear and nonlinear analyses. Reliable and effective finite element procedures are discussed with their applications to the solution of general problems ...
Bonet, J.
We present an implicit a-posteriori finite element procedure to compute bounds for functional outputs of finite element solutions in large strain elasticity. The method proposed relies on the existence of a potential energy ...
Finite element decomposition of the human neocortex
Chow, Seeling
1998-01-01T23:59:59.000Z
Relationships between iso-parametric curves and principal curvature directions, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . ?. ???, . ?. . . . . . . . . . ??. ?. 25 Reparameterizing macro elements for finite element decomposition... . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . 33 Front, top, bottom, left, and right views of the reconstructed neocortex cut through the coronal plane at 38mm from the back, FIGURE Page 34 Middle Temporal Gyrus extracted from the Delaunay triangulation of the neocortex of the right...
FULLYDISCRETE FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY
Ewing, Richard E.
FULLYDISCRETE FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY Zhangxin Chen element method for a nonlinear differential system for describing an airwater system in groundwater experiments using the present approach for modeling groundwater flow in porous media are reported. Key words
Modeling Elastic Properties in Finite-Element Analysis: How Much
Modeling Elastic Properties in Finite- Element Analysis: How Much Precision Is Needed to Produce analysis was investigated using a finite-element model of a Macaca fascicularis skull. Four finite-element realistically using the orthotropic elastic properties employed in analysis 4. Results suggest that finite-element
Techniques for Modeling Muscle-Induced Forces in Finite Element
Dumont, Elizabeth R.
program was written to interface with a commercial finite element analysis tool to automatically apply: finite element analysis; muscle force; skull; muscle loading alogorithm, biting Finite element analysisTechniques for Modeling Muscle- Induced Forces in Finite Element Models of Skeletal Structures IAN
JOURNAL OF MATERIALS SCIENCE 38 (2003) 307 322 Crystal plasticity-based finite element analysis
Grujicic, Mica
2003-01-01T23:59:59.000Z
JOURNAL OF MATERIALS SCIENCE 38 (2003) 307 322 Crystal plasticity-based finite element analysis -TiAl + 2-Ti3Al alloys has been analyzed using a finite element method. A three-dimensional rate interfaces and colony boundaries are implemented in the commercial finite element program Abaqus
Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models
Sarkar, Sudeep
Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models Leonid V. Tsap finite element models. The method is based on the iterative analysis of the differences betweenÃPhysically-based vision, deformable models, nonrigid motion analysis, biomedical applications, finite element analysis. Ã¦
Finite Elements in Analysis and Design 42 (2006) 580591 www.elsevier.com/locate/finel
Li, Shaofan
2006-01-01T23:59:59.000Z
Finite Elements in Analysis and Design 42 (2006) 580591 www numerical Green's functions, for example bubble functions, #12;X. Liu, S. Li / Finite Elements in Analysis.elsevier.com/locate/finel A variational multiscale stabilized finite element method for the Stokes flow problem Xiaohu Liu , Shaofan Li
A cracked beam finite element for rotating shaft dynamics and stability analysis
Paris-Sud XI, Université de
A cracked beam finite element for rotating shaft dynamics and stability analysis Saber El Arem Palaiseau, France Abstract In this paper, a method for the construction of a cracked beam finite element is presented. The additional flexibility due to the cracks is identified from three- dimensional finite element
Finite Elements in Analysis and Design 43 (2007) 397410 www.elsevier.com/locate/finel
Ghosh, Somnath
2007-01-01T23:59:59.000Z
Finite Elements in Analysis and Design 43 (2007) 397410 www.elsevier.com/locate/finel Modeling introduces an extended Voronoi cell finite element model (X-VCFEM) for modeling the initiation: The extended Voronoi cell finite element method (X-VCFEM); Cohesive zone models; Interfacial debonding; Matrix
Quadrilateral/hexahedral finite element mesh coarsening
Staten, Matthew L; Dewey, Mark W; Scott, Michael A; Benzley, Steven E
2012-10-16T23:59:59.000Z
A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.
Hanson, Floyd B.
Optimal control of drug delivery to brain tumors for a PDE driven model using the Galerkin finite is used to examine the optimal drug delivery to brain tumors. The PDE driven mathematical model and the drug concentration. An optimal control problem is formulated keeping in mind the primary goals
Gieras, J.F.; Wing, M. [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Electrical Engineering] [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Electrical Engineering; Santini, E. [Univ. of Rome (Italy). Dept. of Electrical Engineering] [Univ. of Rome (Italy). Dept. of Electrical Engineering
1998-09-01T23:59:59.000Z
The synchronous reactances of permanent magnet (PM) motors have been determined using: (1) analytical method, i.e., form factors of the stator field (armature reaction factors), (2) finite element method (FEM), and (3) experimental tests on a special machine set. The analytical method is widely used in calculations of synchronous reactances of salient pole synchronous machines with electromagnetic excitation. Rotors of PM synchronous machines have more complicated structures, hence it is more difficult to predict accurately the magnetic field distribution in their airgaps in order to find the form factors of the stator field. Numerical methods of field analysis can easily solve this problem. The FEM can predict both the synchronous and mutual (armature reaction) reactances in the d and q axes. The leakage reactance can then be evaluated as a difference between synchronous and mutual reactances. As an example, a small, three-phase, four-pole motor with SmCo surface mounted PM`s (three parallel magnets per pole), and mild-steel pole shoes has been investigated. Such a complicated rotor structure has been intentionally designed in order to be able to compare the advantages and disadvantages of the analytical method and the FEM. In the FEM, the reactances have been calculated using both the flux linkage and current/energy perturbation method. Synchronous reactances as functions of the stator current and load angle obtained analytically from the FEM modeling and from measurements have been compared.
Guaranteed Verification of Finite Element Solutions of Heat Conduction
Wang, Delin
2012-07-16T23:59:59.000Z
. . . . . . . . . . . . . . . . . . 67 4.2 Heat transition problem in one dimension. The effectivity indices ? based on the exact solution u? and ?Sp+k?h? = ESp+k?h? /||eh||C based on the finite element solution u?Sp+k?h? (k = 1, 2, 3, and ?h? from the nest subdivision... ? based on the exact solution u? and ?Sp+k?h? = ESp+k?h? /||eh||C based on the finite element solution u?Sp+k?h? (k = 1, 2, 3, and ?h? from the nest subdivision of the original mesh ?h) of elliptic reconstruction problem obtained with hp method...
Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING
Dennis, Brian
1 Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING OF REALISTIC 3-D Rapid cooling of the brain in the first minutes following the onset of cerebral ischemia is a potentially attractive preservation method. This computer modeling study was undertaken to examine brain-cooling
Yosibash, Zohar
1997-01-01T23:59:59.000Z
; Beer-Sheva; Israel SUMMARY This paper presents a new method for accurate pointwise stress extraction value stresses. The method, denoted by SEC (Stress Extraction by Complementary principle), is based, and indirect extraction methods should be sought. Indirect computation of stresses have been shown
B-spline finite elements for plane elasticity problems
Aggarwal, Bhavya
2007-04-25T23:59:59.000Z
functions. This work focuses on the implementation and comparison of the B-spline finite elements in contrast with the conventional finite elements. This thesis observes that the use of B-spline interpolation functions can reduce the computational cost...
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
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)
Analysis of PostProcessing for Nonconforming Finite Element Solutions
Schieweck, Friedhelm
Analysis of PostProcessing for Nonconforming Finite Element Solutions F. Schieweck \\Lambda of a conforming finite element function v C h 2 V C h . One ``nice'' feature of our analysisprocessing procedure where a conforming approximation is computed from a nonconforming finite element solution
STATIC ANALYSIS OF SANDWICH PLATES BY FINITE ELEMENTS
Paris-Sud XI, Université de
STATIC ANALYSIS OF SANDWICH PLATES BY FINITE ELEMENTS V. MANET, W.-S. HAN AND A. VAUTRIN ´Ecole des continuity at hal-00663233,version1-26Jan2012 #12;Static analysis of sandwich plates by finite elements 3 and are presented in this paper. 2. Hybrid sandwich finite elements In this section, we present the development
Modeling Masticatory Muscle Force in Finite Element Analysis
Modeling Masticatory Muscle Force in Finite Element Analysis: Sensitivity Analysis Using Principal: electromyography; muscle force; mastication; primates; principal coordinates analysis; finite element analysis Our Origins, University of Arizona, Tempe, Arizona ABSTRACT Our work on a finite element model of the skull
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
Medially Based Meshing with Finite Element Analysis of Prostate Deformation Jessica R. Crouch1 have approached prostate imaging problems using meth- ods that incorporate finite element analysis. Assume the prostate is a linearly elastic body and compute its deformation using finite element analysis
Automated Finite Element Analysis for Deformable Registration of Prostate Images
1 Automated Finite Element Analysis for Deformable Registration of Prostate Images Jessica R, Marco Zaider Abstract-- Two major factors preventing the routine clinical use of finite element analysis the effort required to apply finite element analysis to image registration. Encouraging results are presented
FINITE ELEMENT ANALYSIS OF A CLASS OF STRESSFREE MARTENSITIC MICROSTRUCTURES
Li, Bo
FINITE ELEMENT ANALYSIS OF A CLASS OF STRESSFREE MARTENSITIC MICROSTRUCTURES BO LI Abstract. This work is concerned with the finite element approximation of a class of stressfree martensitic microstructures modeled by multiwell en ergy minimization. Finite element energyminimizing sequences are first
A finite element analysis of pneumatic-tire/sand interactions
Grujicic, Mica
A finite element analysis of pneumatic-tire/sand interactions during off-road vehicle travel M pneumatic tire and sand during off-road vehicle travel. Keywords Finite element analysis, Road vehicles and for other tire/sand combinations. Since the finite element analysis of the tire/sand interaction enables
Static Analysis of Sandwich Plates by Hybrid Finite Elements
Paris-Sud XI, Université de
Static Analysis of Sandwich Plates by Hybrid Finite Elements V. Manet and W.-S. Han Materials analysis tool. The subject of the present work concerns the development of hybrid sandwich finite elements into acount. The present work concerns the development of hybrid sandwich finite elements mod- elling
Building Finite Element Analysis Programs in Distributed Services Environment
Stanford University
1. Building Finite Element Analysis Programs in Distributed Services Environment Jun Peng1 and Kincho H. Law2 Abstract Traditional finite element analysis (FEA) programs are typically built on a dedicated computer using the developments offered by a finite element analysis (FEA) program. Typically
Mathur, Anuj
1994-01-01T23:59:59.000Z
in the L-shaped domain shown in Figs. la-ld. We applied boundary condi- 1 tions consistent with the singular solution u(r, 8) = rr sin(-) in the infinite wedge (see also Chapter II) and we assumed that we are interested only in the solution in the hol...-element solution in the subdomain. In Fig. l. la we show an adaptive finite-element mesh which was gener- ated using remeshing and linear elements, over the L-shaped domain fl. For this mesh an accuracy of 1. 09% for the relative error in the energy-norm over...
A Quadrature Finite Element Galerkin Scheme for a Biharmonic Problem on a Rectangular Polygon
Aitbayev, Rakhim
to the OSC method (see [3]), which uses Gaussian quadrature nodes as collocation points and a finite elementA Quadrature Finite Element Galerkin Scheme for a Biharmonic Problem on a Rectangular Polygon with an underdetermined orthogonal spline collocation scheme. © 2007 Wiley Periodicals, Inc. Numer Methods Partial
Impeller deflection and modal finite element analysis.
Spencer, Nathan A.
2013-10-01T23:59:59.000Z
Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.
Tetrahedral hp finite elements: Algorithms and flow simulations
Sherwin, S.J.; Karniadakis, G.E. [Brown Univ., Providence RI (United States)] [Brown Univ., Providence RI (United States)
1996-03-01T23:59:59.000Z
We present a new discretisation for the incompressible Navier-Stokes equations that extends spectral methods to three-dimensional complex domains consisting of tetrahedral subdomains. The algorithm is based on standard concepts of hp finite elements as well as tensorial spectral elements. This new formulation employs a hierarchical/modal basis constructed from a new apex co-ordinate system which retains a generalised tensor product. These properties enable the development of computationally efficienct algorithms for use on standard finite volume unstructed meshes. A detailed analysis is presented that documents the stability and exponential convergence of the method and several flow cases are simulated and compared with analytical and experimental results. 34 refs., 28 figs., 1 tab.
George A. Zyvoloski; Bruce A. Robinson; Zora V. Dash; Lynn L. Trease
1997-07-01T23:59:59.000Z
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.
Geodesic Finite Elements of Higher Order Oliver Sander
conditions. As a side product we can define geodesic finite elements for non-simplex reference elements of a simplex by the weighted average (v1, . . . , dd+1; w) := arg min qM d+1 i=1 wi dist(vi, q)2 , (1) where w are barycentric coordinates on the simplex. Based on this formula a finite element theory could be constructed
Ewing, Richard E.
A ThreeDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination of South Carolina, Columbia, South Carolina ABSTRACT: Model equations for transport of nuclearwaste based up on the inherent physics. A threedimensional finite element method for nuclear waste
Implementation of B-splines in a Conventional Finite Element Framework
Owens, Brian C.
2010-01-16T23:59:59.000Z
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...
Bending buckling of single-walled carbon nanotubes by atomic-scale finite element
Jiang, Hanqing
- vered SWNT loaded by a follower lateral force at the free end and found that it exhibited local bucklingBending buckling of single-walled carbon nanotubes by atomic-scale finite element X. Guo a , A Abstract This paper employs the atomic-scale finite element method to study bending buckling of single
Finite Elements in Analysis and Design 40 (2004) 16191640 www.elsevier.com/locate/nel
Ghosh, Somnath
2004-01-01T23:59:59.000Z
Finite Elements in Analysis and Design 40 (2004) 16191640 www.elsevier.com/locate/ÿnel Two scale. Raghavan et al. / Finite Elements in Analysis and Design 40 (2004) 16191640 performed by the method-scale analysis of composite structures with non-uniform microstructural heterogeneities as obtained from optical
FINITE ELEMENT ANALYSIS OF A BENDING MOMENT FORMULATION FOR THE VIBRATION PROBLEM OF A
Rodríguez, Rodolfo
FINITE ELEMENT ANALYSIS OF A BENDING MOMENT FORMULATION FOR THE VIBRATION PROBLEM OF A NON-order finite element method for approximating the vibration frequencies and modes of a non of the vibration modes, as well as a double order of convergence for the vibration frequencies. These estimates
CONVERGENCE ANALYSIS OF A QUADRATURE FINITE ELEMENT GALERKIN SCHEME FOR A BIHARMONIC PROBLEM
Aitbayev, Rakhim
of the quadrature problem with an orthogonal spline collocation problem. Key words: biharmonic problem, finite elements, Galerkin method, Gaussian quadrature, orthogonal spline collocation AMS subject classificationCONVERGENCE ANALYSIS OF A QUADRATURE FINITE ELEMENT GALERKIN SCHEME FOR A BIHARMONIC PROBLEM RAKHIM
FINITE-ELEMENT FORMULATIONS FOR PROBLEMS OF LARGE ELASTIC-PLASTIC DEFORMATION
FINITE-ELEMENT FORMULATIONS FOR PROBLEMS OF LARGE ELASTIC-PLASTIC DEFORMATION R. M. MCM~EKING and J elastic-plastic flow.The method is based on Hill's variational principle for incremental deformations in a manner which allows any conventions finite element program, for "small strain" elastic-plastic analysis
A finite element multigrid preconditioner for Chebyshev–collocation ...
2000-03-20T23:59:59.000Z
Keywords: Multigrid; Preconditioning; Finite element; Chebyshev–collocation. 1. .... Mi be the restriction of A on Mi; Qi,Pi :M ? Mi be the orthogonal projections.
Algebraic multigrid for stabilized finite element discretizations of the Navier Stokes equation
Okusanya, Tolulope Olawale, 1972 -
2002-01-01T23:59:59.000Z
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 ...
An Inverse Finite Element Analysis and A Parametric Study of Small Punch Tests
Xu, Zhenzhen
2012-02-14T23:59:59.000Z
the effects of SPT parameters including friction coefficient, punch head diameter, sample thickness, specimen scale and boundary conditions. The proposed inverse finite element (FE) method improves the accuracy of existing inverse FE methods...
Energy conserving Anisotropic Anhysteretic Magnetic Modelling for Finite Element Analysis
Jens Krause
2012-12-20T23:59:59.000Z
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.
Finite element analysis of heat transport in a hydrothermal zone
Bixler, N.E.; Carrigan, C.R.
1987-01-01T23:59:59.000Z
Two-phase heat transport in the vicinity of a heated, subsurface zone is important for evaluation of nuclear waste repository design and estimation of geothermal energy recovery, as well as prediction of magma solidification rates. Finite element analyses of steady, two-phase, heat and mass transport have been performed to determine the relative importance of conduction and convection in a permeable medium adjacent to a hot, impermeable, vertical surface. The model includes the effects of liquid flow due to capillarity and buoyancy and vapor flow due to pressure gradients. Change of phase, with its associated latent heat effects, is also modeled. The mechanism of capillarity allows for the presence of two-phase zones, where both liquid and vapor can coexist, which has not been considered in previous investigations. The numerical method employs the standard Galerkin/finite element method, using eight-node, subparametric or isoparametric quadrilateral elements. In order to handle the extreme nonlinearities inherent in two-phase, nonisothermal, porous-flow problems, steady-state results are computed by integrating transients out to a long time (a method that is highly robust).
Spectral/hp Finite Element Models for Fluids and Structures
Payette, Gregory
2012-07-16T23:59:59.000Z
We consider the application of high-order spectral/hp finite element technology to the numerical solution of boundary-value problems arising in the fields of fluid and solid mechanics. For many problems in these areas, high-order finite element...
Gogineni, Sireesha
2011-10-21T23:59:59.000Z
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...
Finite element decomposition and grid generation for brain modeling and visualization
Batte, David Allan
1997-01-01T23:59:59.000Z
Numerical grid generation is used to provide a framework for brain and neuron visualization. Smoothing spline surfaces are fit to contour data to generate 3D solid model reconstruction of brain tissues. Finite element methods are then used...
Biffle, J.H.
1993-02-01T23:59:59.000Z
JAC3D is a three-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equation. The method is implemented in a three-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. An eight-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic-plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere.
Finite element study of Lamb waves: modeling techniques and applications
Verdict, Gregory Scott
1993-01-01T23:59:59.000Z
and theoretical results. In addition, other finite element work shows the viability of using these modeling techniques as a tool for understanding the interaction of Lamb waves with physical defects. As a signal processing tool, neural networks will process...
1 INTRODUCTION Nowadays, geomechanical finite-element codes
Paris-Sud XI, Université de
1 INTRODUCTION Nowadays, geomechanical finite-element codes running on modern computers allow for years. Geotechnical characterization, geophysical surveys and geomechanical modelling have been in geomechanical modelling. In particular, seismic and borehole data, obtained during previous campaigns, are used
NORTHWESTERN UNIVERSITY Finite Element Analysis of TDR Cable-Grout-Soil Mass
NORTHWESTERN UNIVERSITY Finite Element Analysis of TDR Cable-Grout-Soil Mass Interaction During............................................................................................ 13 Finite Element Analysis of Cable Shear Test............................................................................................ 22 Finite Element Analysis of Grout-Cable Composite Shear Test .................................. 25
Progress in Developing Finite Element Models Replicating Flexural Graphite Testing
Robert Bratton
2010-06-01T23:59:59.000Z
This report documents the status of flexural strength evaluations from current ASTM procedures and of developing finite element models predicting the probability of failure. This work is covered under QLD REC-00030. Flexural testing procedures of the American Society for Testing and Materials (ASTM) assume a linear elastic material that has the same moduli for tension and compression. Contrary to this assumption, graphite is known to have different moduli for tension and compression. A finite element model was developed and demonstrated that accounts for the difference in moduli tension and compression. Brittle materials such as graphite exhibit significant scatter in tensile strength, so probabilistic design approaches must be used when designing components fabricated from brittle materials. ASTM procedures predicting probability of failure in ceramics were compared to methods from the current version of the ASME graphite core components rules predicting probability of failure. Using the ASTM procedures yields failure curves at lower applied forces than the ASME rules. A journal paper was published in the Journal of Nuclear Engineering and Design exploring the statistical models of fracture in graphite.
Surface photovoltage measurements and finite element modeling of SAW devices.
Donnelly, Christine
2012-03-01T23:59:59.000Z
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.
Lin, Liwei
Introduction to Finite Element Modeling Engineering analysis of mechanical systems have been of the FEM (don't misuse the FEM - a numerical tool) Finite Element Analysis A typical finite element quantities (e.g., strains and stresses) at selected elements Basic Theory The way finite element analysis
Experimental and finite element analysis of high pressure packer elements
Berger, Stephanie, 1981-
2004-01-01T23:59:59.000Z
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 ...
CharacteristicGalerkin and Mixed Finite Element Approximation of Contamination by Compressible
Chou, So-Hsiang
for the brine, radionuclides, and heat and by a mixed finite element method for the pressure and velocity disposal buried in a salt dome. The salt dissolves to generate a brine, radioactive elements decay), the viscosity of the fluid, is dependent on â?? c, the concentration of the brine in the fluid. For simplicity we
FINITE ELEMENTS AND FINITE DIFFERENCE HUMAN HEAD MODELING: FORWARD PROBLEM
Lowd, Daniel
.T. Vetterling, B.P. Flannery, The Numerical Recipes in C: The art of Scientific Computing, 2nd edition. New York/MEG Fundamental problems in electroencephalography (EEG) and magnetoencephalograpy (MEG), in particular , source DISCUSSION AND FUTURE RESEARCH When using FD methods one should be aware about the following "pros" and "cons
Parallel finite element algorithm for three dimensional ...
methods for electromagnetic induction. INTRODUCTION. N umerical modelling of three dimensional conductivity structures in the earth has experienced a rapid ...
Preprint version, February 2006 to appear in Acta Numerica (2006) Finite element exterior calculus,
2006-01-01T23:59:59.000Z
problem being solved. In the finite element exterior calculus, many finite element spaces are re- vealed-dimensional subspace of the given #12;Finite element exterior calculus 3 function space where the solution isPreprint version, February 2006 to appear in Acta Numerica (2006) Finite element exterior calculus
Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint
Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.
2014-01-01T23:59:59.000Z
This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order of magnitude more efficient that low-order finite elements for a given accuracy level. Interpolation of the three-dimensional rotation, a major technical barrier in large-deformation simulation, is discussed in the context of LSFEs. It is shown, by numerical example, that the high-order LSFEs, where weak forms are evaluated with nodal quadrature, do not suffer from a drawback that exists in low-order finite elements where the tangent-stiffness matrix is calculated at the Gauss points. Finally, the new LSFE code is implemented in the new FAST Modularization Framework for dynamic simulation of highly flexible composite-material wind turbine blades. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples showing validation and LSFE performance will be provided in the final paper.
Study of the mixed finite volume method for Stokes and Navier-Stokes equations
Droniou, Jérôme
(without "orthogonality" assumptions as for classical finite volume methods) and in any space dimension. We methods: finite element methods, mostly used by the mathematician community (see for example [10, 11, 12, and for example to [2, 13, 8, 9] for collocated finite volume schemes). One reason for this difference of practice
Grujicic, Mica
2005-01-01T23:59:59.000Z
Materials Science and Engineering B 117 (2005) 5361 Finite element analysis-based design A finite element method-based procedure is developed for the design of molecularly functionalized nano of a fluid-flow control nano-valve. The results obtained suggest that the finite element-based procedure
California at Berkeley, University of
APPLICATIONS OF ALGEBRAIC MULTIGRID TO LARGE-SCALE FINITE ELEMENT ANALYSIS OF WHOLE BONE MICRO,5 Abstract. Accurate micro-finite element analyses of whole bones require the solution of large sets architectures. Key words. multigrid, trabecular bone, human vertebral body, finite element method, massively
Experimentally validated finite element model of electrocaloric multilayer ceramic structures
Smith, N. A. S., E-mail: nadia.smith@npl.co.uk, E-mail: maciej.rokosz@npl.co.uk, E-mail: tatiana.correia@npl.co.uk; Correia, T. M., E-mail: nadia.smith@npl.co.uk, E-mail: maciej.rokosz@npl.co.uk, E-mail: tatiana.correia@npl.co.uk [National Physical Laboratory, Hampton Road, TW11 0LW Middlesex (United Kingdom); Rokosz, M. K., E-mail: nadia.smith@npl.co.uk, E-mail: maciej.rokosz@npl.co.uk, E-mail: tatiana.correia@npl.co.uk [National Physical Laboratory, Hampton Road, TW11 0LW Middlesex (United Kingdom); Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom)
2014-07-28T23:59:59.000Z
A novel finite element model to simulate the electrocaloric response of a multilayer ceramic capacitor (MLCC) under real environment and operational conditions has been developed. The two-dimensional transient conductive heat transfer model presented includes the electrocaloric effect as a source term, as well as accounting for radiative and convective effects. The model has been validated with experimental data obtained from the direct imaging of MLCC transient temperature variation under application of an electric field. The good agreement between simulated and experimental data, suggests that the novel experimental direct measurement methodology and the finite element model could be used to support the design of optimised electrocaloric units and operating conditions.
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01T23:59:59.000Z
The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.
Abundant p-singular elements in finite classical groups
Niemeyer, Alice C; Praeger, Cheryl E
2012-01-01T23:59:59.000Z
In 1995, Isaacs, Kantor and Spaltenstein proved that for a finite simple d-dimensional classical group G, and for any prime divisor p of |G| distinct from the characteristic, the proportion of p-singular elements (elements with order divisible by p) is at least c/d for some constant c. We define a new subfamily of p-singular elements, called p-abundant elements, which leave invariant certain "large" subspaces of the natural G-module. We find explicit upper and lower bounds for the proportion of p-abundant elements in G, and prove that it approaches a (positive) limiting value as d \\rightarrow \\infty. It turns out that the limiting proportion of p-abundant elements is at least a constant multiple of the lower bound for the proportion of all p-singular elements derived by Issacs, Kantor and Spaltenstein.
Paris-Sud XI, Université de
2002-01-01T23:59:59.000Z
J. Sulem & M. Cerrolaza (2002): Finite element analysis of the indentation test on rocks with microstructure 1 FINITE ELEMENT ANALYSIS OF THE INDENTATION TEST ON ROCKS WITH MICROSTRUCTURE Published in-117" #12;J. Sulem & M. Cerrolaza (2002): Finite element analysis of the indentation test on rocks
A Finite Element-Multibody Dynamics Co-simulation Methodology Applied to FAST
Suryakumar, Vishvas Samuel
2013-05-02T23:59:59.000Z
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...
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
brachytherapy seeds are presented. 1 Introduction This paper considers finite element techniques for non-rigidly registering three- dimensional prostate images acquired for the purpose of brachytherapy plan- ning and guidance. Brachytherapy involves implanting radioactive seeds in the prostate to treat prostate cancer
Finite element analysis of controlled laser coagulation experiments
Tolat, Nimish Prabodh
1997-01-01T23:59:59.000Z
A mathematical model to predict the effect of laser and tissue parameters on the zone of thermal injury by laser interaction on beef liver is presented. The heat transfer and coagulation process was modeled using a non-linear finite-element model...
Experimental validation of finite element codes for welding deformations
Boyer, Edmond
Experimental validation of finite element codes for welding deformations H. M. Aarbogha,b, , M Institute for Energy Technology, N-2027 Kjeller, Norway. Abstract A single pass Metal Inert Gas welding which numerical codes quantifying welding stresses can be validated. It includes a mov- ing heat source
Finite Element Model of Fracture Formation on Growing Surfaces
Prusinkiewicz, Przemyslaw
Finite Element Model of Fracture Formation on Growing Surfaces Pavol Federl and Przemyslaw-mail: federl|pwp@cpsc.ucalgary.ca Abstract We present a model of fracture formation on surfaces of bilayered materials. The model makes it possible to synthesize patterns of fractures induced by growth or shrinkage
FEWA: a Finite Element model of Water flow through Aquifers
Yeh, G.T.; Huff, D.D.
1983-11-01T23:59:59.000Z
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.
Method for detecting an element
Blackwood, Larry G.; Reber, Edward L.; Rohde, Kenneth W.
2007-02-06T23:59:59.000Z
A method for detecting an element is disclosed and which includes the steps of providing a gamma-ray spectrum which depicts, at least in part, a test region having boundaries, and which has a small amount of the element to be detected; providing a calculation which detects the small amount of the element to be detected; and providing a moving window and performing the calculation within the moving window, and over a range of possible window boundaries within the test region to determine the location of the optimal test region within the gamma-ray spectrum.
FINITE ELEMENT ANALYSIS OF THERMAL TENSIONING TECHNIQUES MITIGATING WELD BUCKLING DISTORTION
Michaleris, Panagiotis
FINITE ELEMENT ANALYSIS OF THERMAL TENSIONING TECHNIQUES MITIGATING WELD BUCKLING DISTORTION. This paper presents a finite element analysis model of the thermal tensioning technique. A series of finite by the finite element simulations, the residual stresses of large size and high heat input welds are reduced
SUBDIVISION SURFACES: A NEW PARADIGM FOR THIN-SHELL FINITE-ELEMENT ANALYSIS
Desbrun, Mathieu
SUBDIVISION SURFACES: A NEW PARADIGM FOR THIN-SHELL FINITE-ELEMENT ANALYSIS Fehmi Cirak1 , Michael for thin-shell finite-element analysis based on the use of subdivision surfaces for: i) describing by subdivision are H2 and, consequently, have a finite Kirchhoff-Love energy. The resulting finite elements
A Mixed Finite Element Approximation for Compressible Flow of Contamination from Nuclear
Chou, So-Hsiang
of this system using a finite element method for the brine, radionuclides, and heat combined with a mixed finite; and Â¯(â??c), the viscosity of the fluid is depenÂ dent on â?? c, the concentration of the brine in the fluid + (ff L \\Gamma ff T )u i u j =juj). Brine: @ @t (OEaeâ??c) = \\Gammar \\Delta (aeâ??cu) +r \\Delta (aeE c (u
Finite element analysis of axisymmetric oscillations of sessile liquid drops
Bixler, N.E.; Benner, R.E.
1985-01-01T23:59:59.000Z
Inviscid oscillations of sessile liquid drops are simulated by the Galerkin finite element method in conjunction with the time integrator proposed by Gresho et al. Simulations are of drops in spherical containers which are subjected to imposed oscillations of specified frequency and amplitude. Five equations govern drop response: (1) Laplace's equation for velocity potential within the drop; (2) a kinematic condition at the free surface; (3) a Bernoulli equation augmented to include gravity and capillary pressure at the free surface; (4) a kinematic condition at the solid surface; and (5) either a condition for fixed contact line or fixed contact angle. Each of these equations is modified to account for an accelerating frame of reference which moves the container. Normalized drop volume, contact angle, and gravitational Bond number are dimensionless parameters which control drop response to an imposed oscillation. Given a set of fluid properties, such as those for mercury, gravitational Bond number is uniquely defined by the container radius. Resonant frequencies and mode interaction are detected by Fourier analysis of a transient signal, such as free surface position at the pole of a spherical coordinate system. Results, especially resonant frequencies, are found to depend strongly on contact line condition. Calculation of resonant frequencies by eigenanalysis with Stewart's method is also discussed. 11 refs., 8 figs.
On Smoothing Surfaces in Voxel Based Finite Element Analysis of Trabecular Bone
Frey, Pascal
On Smoothing Surfaces in Voxel Based Finite Element Analysis of Trabecular Bone Peter Arbenz on complicated domains composed of often hundreds of millions of voxel elements. The finite element analysis finite element (FE) analysis. The approach based on the FE analysis leads to linear systems of equations
James, Stephen M.
2011-08-08T23:59:59.000Z
? Matrix of eigenvectors of rotor [ ]rA ? Component mode synthesis transformation matrix for rotor [ ]XA ? Eigenvector matrix for X Z? plane [ ]YA ? Eigenvector matrix for Y Z? plane , , , b1 b2 b3 b4 ? Bearings used in component... [F] FEA ? Finite element analysis FEM ? Finite element methods ; 1:if i = m ? ith force matrix element in Guyan reduction [F] { }rBF ? Transformed rotor external forces matrix ; 1:rif i m= ? Force acting at the ith station of rotor...
Mohamed, M. Shadi, E-mail: m.s.mohamed@durham.ac.uk [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Seaid, Mohammed; Trevelyan, Jon [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom)] [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Laghrouche, Omar [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)
2013-10-15T23:59:59.000Z
We investigate the effectiveness of the partition-of-unity finite element method for transient conduction–radiation problems in diffusive grey media. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary diffusion approximation to the radiation in grey media. The coupled equations are integrated in time using a semi-implicit method in the finite element framework. We show that for the considered problems, a combination of hyperbolic and exponential enrichment functions based on an approximation of the boundary layer leads to improved accuracy compared to the conventional finite element method. It is illustrated that this approach can be more efficient than using h adaptivity to increase the accuracy of the finite element method near the boundary walls. The performance of the proposed partition-of-unity method is analyzed on several test examples for transient conduction–radiation problems in two space dimensions.
Evaluation of an existing bridge`s modal properties using simplified finite element analysis
Farrar, C.R.; Duffey, T.A.
1996-02-01T23:59:59.000Z
The purpose of this paper is to present results of a simplified approach to the dynamic finite element modeling of composite girder-slab bridges using a single beam element to represent the girder-slab cross section. Dynamic properties calculated with these simplified models are compared to experimental results and results obtained from more detailed shell element models. The method for modeling flexural behavior is first discussed followed by a discussion of modeling torsional behavior. The beam element models accurately calculated the mode shapes of the structure, but the associated resonant frequencies showed some error.
Calibration under uncertainty for finite element models of masonry monuments
Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin
2010-02-01T23:59:59.000Z
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.
Residual stresses in weld overlay tubes: A finite element study
Taljat, B.; Zacharia, T.; Wang, X.L.; Keiser, J.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Feng, Z. [Edison Welding Inst., Columbus, OH (United States); Jirinec, M.J. [Welding Services, Inc., Norcross, GA (United States)
1997-01-03T23:59:59.000Z
Residual stresses and strains in a tube with circumferential weld overlay were analyzed by the finite element (FE) method. The objective of this work was to develop and verify a FE model, to determine the magnitude and distribution of residual stresses in the weld overlay tube, and to evaluate the significance of two contributing factors to residual stress: (1) difference in material properties between tube and weld material, and (2) thermal gradients in the weld. An axisymmetric FE model was developed to simulate the circumferential two-layer welding process of alloy 625 overlay on SA210 tube. The first layer was modeled as a gas metal arc welding process with filler metal, whereas the autogenous gas tungsten arc welding process was modeled for the second layer. Neutron diffraction technique was used to experimentally determine residual elastic strains in the weld overlay tube. Comparison with the FE results shows overall good agreement. Both the experimental and FE results show high compressive stresses at the inside tube surface and high tensile stresses in the weld overlay. This suggests that weld overlay may be used to relieve tensile or produce compressive stresses at the inside tube surface, which is significant for applications where crack initiation is found at the root pass of the joining weld.
A finite element analysis of shrinkage stress fields in two-phase materials
Hall, Frank
1980-01-01T23:59:59.000Z
expansion were determined as constants. A simple finite element model was then analyzed to verify the suit- ability of the code for prediction of restrained shrinkage stress fields. Cree Com lienee Test A series of constant load isothermal creep tests... was judged to be suitable for prediction of shrinkage stress f ields. 0 m ~/0 ? Q ? Beam Bending Theory ? O ? Finite Element Method U o m m a 40 60 Time, min eo 100 120 Figure 8. Vertical deflection at midspan of four point bending test...
Finite Element Modeling of Micromachined MEMS Photon Devices
Datskos, P.G.; Evans, B.M.; Schonberger, D.
1999-09-20T23:59:59.000Z
The technology of microelectronics that has evolved over the past half century is one of great power and sophistication and can now be extended to many applications (MEMS and MOEMS) other than electronics. An interesting application of MEMS quantum devices is the detection of electromagnetic radiation. The operation principle of MEMS quantum devices is based on the photoinduced stress in semiconductors, and the photon detection results from the measurement of the photoinduced bending. These devices can be described as micromechanical photon detectors. In this work, we have developed a technique for simulating electronic stresses using finite element analysis. We have used our technique to model the response of micromechanical photon devices to external stimuli and compared these results with experimental data. Material properties, geometry, and bimaterial design play an important role in the performance of micromechanical photon detectors. We have modeled these effects using finite element analysis and included the effects of bimaterial thickness coating, effective length of the device, width, and thickness.
Finite element analysis of a darcy velocimeter in a variably saturated soil
Bixler, N.E.; Carrigan, C.R.
1989-01-01T23:59:59.000Z
A new device, the Darcy velocimeter, is analyzed by the finite element method. The model is of two-phase flow and heat transport in a porous medium. Both laboratory-and field-scale experiments are simulated. The results show that the device should readily detect groundwater fluxes in the 10 to 100 m/yr range.
Bürger, Raimund
in models of sedimentation Raimund B¨urgera , Sarvesh Kumarb , Ricardo Ruiz-Baierc aCI2MA and Departamento The sedimentation-consolidation and flow processes of a mixture of small particles dispersed in a vis- cous fluid discontinuous finite volume element (DFVE) discretization for this model is pro- posed. The numerical method
Frey, Pascal
2008-01-01T23:59:59.000Z
for glaciers$ A.H. Jarosch Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik Detailed studies of glacier flow and deformation of ice require high-resolution numerical modeling.40.Cy; 92.40.Sn; 92.40.Vq Keywords: Glacier; Finite element method; Full Stokes; Ice 1. Introduction
Piezoelectric theory for finite element analysis of ultrasonic motors
Emery, J.D.; Mentesana, C.P.
1997-06-01T23:59:59.000Z
The authors present the fundamental equations of piezoelectricity and references. They show how a second form of the equations and a second set of coefficients can be found, through inversions involving the elasticity tensor. They show how to compute the clamped permittivity matrix from the unclamped matrix. The authors list the program pzansys.ftn and present examples of its use. This program does the conversions and calculations needed by the finite element program ANSYS.
3-D Finite Element Analyses of the Egan Cavern Field
Klamerus, E.W.; Ehgartner, B.L.
1999-02-01T23:59:59.000Z
Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were moderate to excessive depending on the salt creep properties and operating pressures. However, subsidence above the cavern field was small and should pose no problem, to surface facilities.
An enriched finite element model with q-refinement for radiative boundary layers in glass cooling
Mohamed, M. Shadi [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Seaid, Mohammed; Trevelyan, Jon [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom)] [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Laghrouche, Omar [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)
2014-02-01T23:59:59.000Z
Radiative cooling in glass manufacturing is simulated using the partition of unity finite element method. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary simplified P{sub 1} approximation for the radiation in non-grey semitransparent media. To integrate the coupled equations in time we consider a linearly implicit scheme in the finite element framework. A class of hyperbolic enrichment functions is proposed to resolve boundary layers near the enclosure walls. Using an industrial electromagnetic spectrum, the proposed method shows an immense reduction in the number of degrees of freedom required to achieve a certain accuracy compared to the conventional h-version finite element method. Furthermore the method shows a stable behaviour in treating the boundary layers which is shown by studying the solution close to the domain boundaries. The time integration choice is essential to implement a q-refinement procedure introduced in the current study. The enrichment is refined with respect to the steepness of the solution gradient near the domain boundary in the first few time steps and is shown to lead to a further significant reduction on top of what is already achieved with the enrichment. The performance of the proposed method is analysed for glass annealing in two enclosures where the simplified P{sub 1} approximation solution with the partition of unity method, the conventional finite element method and the finite difference method are compared to each other and to the full radiative heat transfer as well as the canonical Rosseland model.
Implementation of finite element analysis into the athletic shoe design process
Hidalgo, Maria E. (Maria Estela), 1982-
2004-01-01T23:59:59.000Z
Finite element analysis is used by companies throughout the world as a substitution for manually testing prototypes. With the assistance of finite element analysis many companies and industries have decreased the time and ...
Giurgiutiu, Victor
Finite Element Simulation of Piezoelectric Wafer Active Sensors for Structural Health Monitoring) is emerging as an effective and powerful technique in structural health monitoring (SHM). Modeling to analytical calculation and experimental data. Key words: Structural Health Monitoring, PWAS, finite element
Implementation of B-splines in a Conventional Finite Element Framework
Owens, Brian C.
2010-01-16T23:59:59.000Z
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...
An evaluation of finite element models of stiffened plates subjected to impulsive loading
Pedatzur, Omri
2004-01-01T23:59:59.000Z
Different finite element models are evaluated for two very common structures, a cantilever beam and a stiffened plate, subjected to impulsive loading. For the cantilever beam case, the finite element models are one, two ...
Element-based concrete design with three-dimensional finite element models
O'Leary, M.; Huberty, K.; Winch, S. [Nuclear Power Technologies Div., Sargent and Lundy, 55 East Monroe, Chicago, IL 60603 (United States)
2012-07-01T23:59:59.000Z
A shell element based design of a typical shear wall using analytical results from a three-dimensional finite element model subjected to a combination of vertical and lateral loads is evaluated. The axial and flexural force resultants from each element for every load combination are used to calculate the required reinforcing for each element. Strength for axial loads (P) and out-of-plane flexure (M) in structural walls is determined according to the same P-M interaction procedures used for columns. After each element has been evaluated, a required reinforcing map for each face of each element in the wall is presented along with a constructible reinforcement pattern enveloping the required reinforcing. In order to determine whether the element-based approach meets the requirements of the section cut approach to design, which is typically employed in manual calculations, the total in-plane moment (M) and total vertical axial force (P) across the entire length of the wall is calculated and the P-M points are plotted on an in-plane P-M interaction diagram. It is concluded that element-based design for a structural wall ensures that reinforcement is provided where required by the three-dimensional finite element analysis while still providing sufficient reinforcing to satisfy the section cut approach to design. (authors)
FINITE WAVELET DOMAIN METHOD FOR EFFICIENT MODELING OF LAMB WAVE BASED STRUCTURAL HEALTH MONITORING
Paris-Sud XI, Université de
FINITE WAVELET DOMAIN METHOD FOR EFFICIENT MODELING OF LAMB WAVE BASED STRUCTURAL HEALTH MONITORING element exploits the advantages of wavelets for the spatial discretization of the displacement field : Wavelet-based Finite Element, Transient Response. 1 INTRODUCTION The dynamic transient response and wave
Detecting the Causes of Ill-Conditioning in Structural Finite Element Models
Higham, Nicholas J.
.6 of the finite element-based structural analysis package Oasys GSA was released. A new feature in this release
Detecting the causes of ill-conditioning in structural finite element Ramaseshan Kannan b,a
Tisseur, Francoise
.6 of the finite element-based structural analysis package Oasys GSA was released. A new feature in this release
Boyer, Edmond
in the patient head. Yet, the skull anisotropy happens to be highly anisotropic, and must then be modeled.e. for the brain and the scalp). A domain decomposition (DD) framework allows to split the global system. This work presents such a coupling formulation of a 3-DD method solving iteratively a BEM for the brain
Barham, M; White, D; Steigmann, D; Rudd, R
2009-04-08T23:59:59.000Z
Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.
Wear 258 (2005) 17871793 Finite element analysis and experiments of metal/metal
Sawyer, Wallace
2005-01-01T23:59:59.000Z
Wear 258 (2005) 17871793 Finite element analysis and experiments of metal/metal wear-on-disk experiments. The results from the finite element analysis were in close agreement with the block of this simulation. © 2004 Published by Elsevier B.V. Keywords: Wear modeling; Finite element analysis 1
Wrinkle development analysis in thin sail-like structures using MITC shell finite elements
Paris-Sud XI, Université de
Wrinkle development analysis in thin sail-like structures using MITC shell finite elements D submitted to Finite Elements in Analysis and Design September 20, 2012 hal-00733994,version1-20Sep2012 Author manuscript, published in "Finite Elements in Analysis and Design 64 (2013) 48-64" DOI : 10.1016/j
Tolerance Analysis of Flexible Assemblies Using Finite Element and Spectral Analysis
Tolerance Analysis of Flexible Assemblies Using Finite Element and Spectral Analysis ADCATS Report the autocorrelation function from frequency spectrum analysis to model random surface variations. Finite element BACKGROUND LITERATURE REVIEW 5 3 STATISTICAL TOLERANCE ANALYSIS USING FINITE ELEMENT ANALYSIS 3.1 Assumptions
Finite element analysis of performance in the skulls of marmosets and tamarins
Dumont, Elizabeth R.
Finite element analysis of performance in the skulls of marmosets and tamarins Elizabeth R. Dumont compara- tive analyses. Key words finite element analysis; marmoset; performance; tamarin. Introduction. Using 3D finite element models of the marmoset Callithrix jacchus and the tamarin Saguinus fuscicollis
Approximation Theory and Finite Element Analysis January 2014 Lecturer David Silvester
Silvester, David J.
Approximation Theory and Finite Element Analysis January 2014 Lecturer David Silvester Office Alan Analysis, CUP, 2003. · Dietrich Braess, Finite Elements: Theory, Fast Solvers and Applications in Solid Mechanics, CUP, Third Edition, 2007. · Howard Elman, David Silvester and Andy Wathen, Finite Elements
Free Body Analysis, Beam Mechanics, and Finite Element Modeling of the Mandible of Alligator
Free Body Analysis, Beam Mechanics, and Finite Element Modeling of the Mandible of Alligator arm mechanics, 2D and 3D beam mod- els, and three high-resolution finite element models- pared with the beam models, the Alligator finite element models exhibited less spatial variability
The Finite Element Analysis of Quartz Crystal Resonators with Nonlinear Plate Equations
Wang, Ji
The Finite Element Analysis of Quartz Crystal Resonators with Nonlinear Plate Equations Ji Wang1, dujianke, wanglihong}@nbu.edu.cn, yyong@rci.rutgers.edu Abstract--The finite element analysis of quartz for typical thickness-shear vibrations of quartz crystal plates. While linear finite element analysis
Finite Element Analysis of Nonlinear Thickness-shear Vibrations of AT-cut Quartz Crystal Plates
Wang, Ji
Finite Element Analysis of Nonlinear Thickness-shear Vibrations of AT-cut Quartz Crystal Plates Ji, dujianke}@nbu.edu.cn Abstract--The nonlinear finite element analysis is performed with the nonlinear a smaller size in comparison with the 3D approach. General procedure of nonlinear finite element analysis
FINITE ELEMENT ANALYSIS OF A CLASS OF STRESS-FREE MARTENSITIC MICROSTRUCTURES
Li, Bo
FINITE ELEMENT ANALYSIS OF A CLASS OF STRESS-FREE MARTENSITIC MICROSTRUCTURES BO LI Abstract. This work is concerned with the finite element approximation of a class of stress-free martensitic microstructures modeled by multi-well en- ergy minimization. Finite element energy-minimizing sequences are first
Comparison of Beam Theory and Finite-Element Analysis With In Vivo
Comparison of Beam Theory and Finite-Element Analysis With In Vivo Bone Strain Data From structures and, more recently, finite- element (FE) analysis. In this study, we compare experimentally-Liss, Inc. Key words: bone strain; finite-element analysis; skull biome- chanics; alligator; feeding
Finite Elements in Analysis and Design 41 (2004) 253265 www.elsevier.com/locate/finel
Rivero, Jose Pablo SuÃ¡rez
2004-01-01T23:59:59.000Z
Finite Elements in Analysis and Design 41 (2004) 253Â265 www.elsevier.com/locate/finel The 8 favorable in finite element analysis. Furthermore, since a right prism can be subdivided into six right adaptive finite element analysis procedure has received much attention
Miga, Michael I.
A finite element inverse analysis to assess functional improvement during the fracture healing architecture on the FEA estimated material property metric. The finite element model inverse analysis developed i n f o Article history: Accepted 2 September 2009 Keywords: Fracture healing Finite element
A Finite Element Analysis of Masticatory Stress Janine Chalk,1,2
A Finite Element Analysis of Masticatory Stress Hypotheses Janine Chalk,1,2 * Brian G. Richmond,2). This study uses finite element analysis to examine the extent to which these geometric models provide loading regimes, were applied to a previously validated finite element model (FEM) of a macaque (Macaca
Finite Element Analysis of Ultrasonic Processing of a Polymer-Matrix Composite
Roylance, David
Finite Element Analysis of Ultrasonic Processing of a Polymer- Matrix Composite Wenguang Zhao1 parameters, makes trial-and-error analysis of the process difficult, and this paper demonstrates how a finite-element; Ultrasonic Tape Lamination; Viscoelastic dissipation; Finite-element analysis 1. Introduction This paper
Vecchio, Frank J.
Abstract ii NONLINEAR FINITE ELEMENT ANALYSIS OF REINFORCED CONCRETE STRUCTURES SUBJECTED nonlinear finite element transient thermal analysis is implemented into program VecTor2©, a nonlinear's response to thermal loads, this research develops and implements a 2D nonlinear finite element transient
Author's personal copy The effects of modeling simplifications on craniofacial finite element models
a r t i c l e i n f o Article history: Accepted 17 March 2011 Keywords: Finite element analysis Tooth), a biomechanical system commonly studied using finite element analysis (FEA) is that part of the craniofacial in such finite element models (FEMs) depends exten- sively on the objective of the analysis and the performance
Chen, Zheng
-F, July 725, 2014; Final Exam: 1-4 PM, July 26, 2014 Objective To develop an understanding of finite. References 1. D. L. Logan, The First Course in the Finite Element Method, 5th Edition, SI; Cengage Learning Project Assessment (20%) 30% Midterm Exam 10% Final Exam 40% Total 100% #12;
Guaranteed Verification of Finite Element Solutions of Heat Conduction
Wang, Delin
2012-07-16T23:59:59.000Z
Engineering iii ABSTRACT Guaranteed Verification of Finite Element Solutions of Heat Conduction. (May 2011) Delin Wang, B.E., Qingdao University of Science & Technology, China; M.S., Jilin University, China; M.E., Texas A&M University Chair of Advisory... level and ? ky kx is the characteristic thickness of the boundary layer. . . . . 37 3.5 Model problem with interface layer. The relative value of the energy norm of the error ErelU = ||eSp?h ||U / ||uEX||U? 100% versus #15; for n = 1, 2, 3...
Transport and dispersion of pollutants in surface impoundments: a finite element model
Yeh, G.T.
1980-07-01T23:59:59.000Z
A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.
Generalized finite element method for Helmholtz equation
Hidajat, Realino Lulie
2009-05-15T23:59:59.000Z
,0) and its estimator E h;p,q u(?1,0) (d) computed using d/R = 1, with the truncation radius R =1.5. The di?erence between the curve for the Robin and the curves for the SOM, BT1, BT2 boundary conditions is the error due to the artificial boundary condition... results as the ones obtained using the Robin boundary condition. 94 5.9 Location of output points, the domain ? with truncation radius R =2.5 and the employed mesh. ............................ 94 5.10 q-convergence of e h;p,q u(A) using Sommerfeld...
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE ...
2015-06-30T23:59:59.000Z
The research of this author was supported in part by the National Magnetic. Confinement Fusion Science Program under grant 2011GB105003 and by the NSF ...
CONVERGENCE OF A MULTISCALE FINITE ELEMENT METHOD ...
1999-04-17T23:59:59.000Z
Mar 3, 1999 ... In the above proof, ul is used as an intermediate step towards ...... Current address: Exxon Production Research Company, P. O. Box 2189, Houston, TX 77252 ... Department of Mathematics, Purdue University, West Lafayette, ...
Generalized finite element method for multiscale analysis
Zhang, Lin
2004-11-15T23:59:59.000Z
solutions ||uh||U and the overkill solutions ||uov||U. Analytical void functions of order pvoid = 1 were employed for the simple handbook solutions psiX;1/2j . ..................... 30 3.2 Relative errors eGFEMREL (deltah,p,phb; gamma) for Problems I...GFEMREL (deltah,p,phb; gamma) for Problem I(a)-I(d). The approx- imate solutions were computed by employing the handbook functions psiX;1/2j , but no analytical void functions were used in the numerical con- struction of these functions...
PARTIALLY PENALIZED IMMERSED FINITE ELEMENT METHODS ...
2015-01-05T23:59:59.000Z
convergence rate in an energy norm provided that the exact solution has sufficient regularity, but .... energy norm. ...... [15] B. Camp, T. Lin, Y. Lin, and W. Sun.
Cambridge, University of
Element Analysis, H. K. D. H. Bhadeshia Lecture 2: Finite Elements In finite element analysis, functions to be homogeneous. In finite element stress analysis, the elastic body is first divided into discrete connected. Thus, a finite element representation of a circle would be a circumscribed polygon, with each edge
Finite element visualization in the cave virtual reality environment
Plaskacz, E.J. [Argonne National Lab., IL (United States); Kuhn, M.A. [Northern Illinois Univ., De Kalb, IL (United States)
1996-03-01T23:59:59.000Z
Through the use of the post-processing software, Virtual Reality visualization (VRviz), and the Cave Automatic Virtual Environment (CAVE), finite element representations can be viewed as they would be in real life. VRviz is a program written in ANSI C to translate the mathematical results generated by finite element analysis programs into a virtual representation. This virtual representation is projected into the CAVE environment and the results are animated. The animation is fully controllable. A user is able to translate the image, rotate about any axis and scale the image at any time. The user is also able to freeze the animation at any time step and control the image update rate. This allows the user to navigate around, or even inside, the image in order to effectively analyze possible failure points and redesign as necessary. Through the use of the CAVE and the real life image that is being produced by VRviz, engineers are able to save considerable time, money, and effort in the design process.
A Finite Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2013-11-02T23:59:59.000Z
We present a hydro-mechanical model, followed by stress, deformation, and shear-slip failure analysis for geological sequestration of carbon dioxide (CO2). The model considers the poroelastic effects by taking into account of the two-way coupling between the geomechanical response and the fluid flow process. Analytical solutions for pressure and deformation fields were derived for a typical geological sequestration scenario in our previous work. A finite element approach is introduced here for numerically solving the hydro-mechanical model with arbitrary boundary conditions. The numerical approach was built on an open-source finite element code Elmer, and results were compared to the analytical solutions. The shear-slip failure analysis was presented based on the numerical results, where the potential failure zone is identified. Information is relevant to the prediction of the maximum sustainable injection rate or pressure. The effects of caprock permeability on the fluid pressure, deformation, stress, and the shear-slip failure zone were also quantitatively studied. It was shown that a larger permeability in caprock and base rock leads to a larger uplift but a smaller shear-slip failure zone.
The Uranium Processing Facility Finite Element Meshing Discussion
Office of Environmental Management (EM)
more nodes and elements (1 element 9 elements) - Changed from GTStrudl to SAP 2000. - Linear elastic computer model * DOE Project 2 - 15'-20' element size deemed...
Finite element analyses of a linear-accelerator electron gun
Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk, E-mail: muniqbal@ihep.ac.cn [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wasy, A. [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of)] [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)] [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
2014-02-15T23:59:59.000Z
Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000?°C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.
FINITE ELEMENT ANALYSIS OF BULK TRITIUM SHIPPING PACKAGE
Jordan, J.
2010-06-02T23:59:59.000Z
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.
Cambridge, University of
Element Analysis, H. K. D. H. Bhadeshia Lecture 3: Finite Elements Steadystate heat flow through A and length L. The finite element representation consists of two nodes i and j. Heat flow in one. The temperatures T1 and T2 are maintained constant. The finite element representation consists of a single element
SEACAS Theory Manuals: Part III. Finite Element Analysis in Nonlinear Solid Mechanics
Laursen, T.A.; Attaway, S.W.; Zadoks, R.I.
1999-03-01T23:59:59.000Z
This report outlines the application of finite element methodology to large deformation solid mechanics problems, detailing also some of the key technological issues that effective finite element formulations must address. The presentation is organized into three major portions: first, a discussion of finite element discretization from the global point of view, emphasizing the relationship between a virtual work principle and the associated fully discrete system, second, a discussion of finite element technology, emphasizing the important theoretical and practical features associated with an individual finite element; and third, detailed description of specific elements that enjoy widespread use, providing some examples of the theoretical ideas already described. Descriptions of problem formulation in nonlinear solid mechanics, nonlinear continuum mechanics, and constitutive modeling are given in three companion reports.
A finite element simulation of biological conversion processes in landfills
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
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.
Solar Electric Generating System II finite element analysis
Dohner, J.L.; Anderson, J.R.
1994-04-01T23:59:59.000Z
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.
FEMA: a Finite Element Model of Material Transport through Aquifers
Yeh, G.T.; Huff, D.D.
1985-01-01T23:59:59.000Z
This report documents the construction, verification, and demonstration of a Finite Element Model of Material Transport through Aquifers (FEMA). The particular features of FEMA are its versatility and flexibility to deal with as many real-world problems as possible. Mechanisms included in FEMA are: carrier fluid advection, hydrodynamic dispersion and molecular diffusion, radioactive decay, sorption, source/sinks, and degradation due to biological, chemical as well as physical processes. Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Prescribed concentration on the Dirichlet boundary, given gradient on the Neumann boundary segment, and flux at each Cauchy boundary segment can vary independently of each other. The aquifer may consist of as many formations as desired. Either completely confined or completely unconfined or partially confined and partially unconfined aquifers can be dealt with effectively. FEMA also includes transient leakage to or from the aquifer of interest through confining beds from or to aquifers lying below and/or above.
Prediction of a Mysticete Audiogram via Finite Element Analysis of the Middle Ear
Prediction of a Mysticete Audiogram via Finite Element Analysis of the Middle Ear Andrew Tubelli (Rosowski 1994). Biophysical models of the cetacean middle ear can be developed using finite element (FE for FE analysis (COMSOL, Stockholm, Sweden). _________________________ A. Tubelli (!) · A. Zosuls · D
STATISTICAL AND 3D NONLINEAR FINITE ELEMENT ANALYSIS OF SCHLEGEIS DAM
Balaji, Rajagopalan
STATISTICAL AND 3D NONLINEAR FINITE ELEMENT ANALYSIS OF SCHLEGEIS DAM VICTOR SAOUMA, ERIC HANSEN is composed of two parts. First a statistical analysis of the dam crest displacement is performed, along with a prediction for the years 2000-2001. Then a 3D finite element analysis of Schlegeis dam is performed using
Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls
Bruneau, Michel
Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls.k.a. perforated SPSW . Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips with variation in perforation diameter, to develop a fundamental understanding
FINITE ELEMENT INVESTIGATION AND DESIGN RECOMMENDATIONS FOR PERFORATED STEEL PLATE SHEAR WALLS
Bruneau, Michel
FINITE ELEMENT INVESTIGATION AND DESIGN RECOMMENDATIONS FOR PERFORATED STEEL PLATE SHEAR WALLS of the behavior of unstiffened thin SPSW having a regular pattern of openings (a.k.a. perforated SPSW). Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips
A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS
A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS Dirk Büche Aluminum devices such as compressor wheels are typically heat treated in order to achieve the required
Equal-order finite elements with local projection stabilization for the Darcy-Brinkman equations
Schieweck, Friedhelm
Equal-order finite elements with local projection stabilization for the Darcy-Brinkman equations M. Braack and F. Schieweck Mai 2010 Abstract For the Darcy-Brinkman equations, which model porous media: Porous media flow, Darcy-Brinkman equations, Stokes, equal-order finite elements, local projection
thickness using finite-element analysis David S. Strait a,*, Brian G. Richmond b , Mark A. Spencer c which early hominid features are functionally related to chewing. This paper uses finite-element Paranthropus synapomorphies putatively related to mastication. A finite-element model of 145,680 elements
Low frequency eddy current finite element model validation and benchmark studies
Cherry, M.; Knopp, J. [Materials and Manufacturing Directorate, Air Force Research Laboratory (United States); Mooers, R.; Boehnlein, T. [University of Dayton Research Institute, Dayton, OH (United States); Aldrin, J. C. [Computational Tools, Gurnee, IL (United States); Sabbagh, H. A. [Victor Technologies, LLC, Bloomington, IN (United States)
2011-06-23T23:59:59.000Z
A finite element method (FEM) model was created to calculate the change in impedance of a coil due to the presence of a notch in a plate. The rectangular notches were created via electrical discharge machining (EDM) in a thick aluminum plate and were positioned at normal and oblique angles (10, 20, and 30 degrees) with respect to the vertical axis of the coil. The FEM method was chosen for this model due to its ability to solve problems in complicated geometries with the use of irregular mesh elements to discretize the solution domain. The change in impedance was calculated from the field variables in the simulation for each probe position along the parallel axis of the plate. The error between the model and the experimental data was approximately 5% for the majority of cases. The validated model was used to investigate more complex problems.
Method of lightening radiation darkened optical elements
Reich, Frederich R. (Richland, WA); Schwankoff, Albert R. (W. Richland, WA)
1980-01-01T23:59:59.000Z
A method of lightening a radiation-darkened optical element in wich visible optical energy or electromagnetic radiation having a wavelength in the range of from about 2000 to about 20,000 angstroms is directed into the radiation-darkened optical element; the method may be used to lighten radiation-darkened optical element in-situ during the use of the optical element to transmit data by electronically separating the optical energy from the optical output by frequency filtering, data cooling, or interlacing the optic energy between data intervals.
Multigrid for Higher Order Discontinuous Galerkin Finite Elements Applied to Groundwater Flow
Bastian, Peter
Multigrid for Higher Order Discontinuous Galerkin Finite Elements Applied to Groundwater Flow Peter elements applied to the groundwater flow equation. It uses an incomplete LU decomposition on an element for diffusion problems has been formu- lated in [6]. 1.1 Notation In this paper we wish to solve the groundwater
Spectral analysis method for detecting an element
Blackwood, Larry G [Idaho Falls, ID; Edwards, Andrew J [Idaho Falls, ID; Jewell, James K [Idaho Falls, ID; Reber, Edward L [Idaho Falls, ID; Seabury, Edward H [Idaho Falls, ID
2008-02-12T23:59:59.000Z
A method for detecting an element is described and which includes the steps of providing a gamma-ray spectrum which has a region of interest which corresponds with a small amount of an element to be detected; providing nonparametric assumptions about a shape of the gamma-ray spectrum in the region of interest, and which would indicate the presence of the element to be detected; and applying a statistical test to the shape of the gamma-ray spectrum based upon the nonparametric assumptions to detect the small amount of the element to be detected.
McCready, Mark J.
Version: 6/16/98 Keywords: wavy surface flow, finite element, longwave analysis, weakly and drag are found, from finite element calculations, to increase as amplitude to approximately the third wavelength problem is solved numerically with a finite element formulation providing qualitative trends
Miga, Michael I.
A Novel Inverse Finite Element Analysis to Assess Bone Fracture Healing in Mice Receiving Bone generation, and an iterative optimization (using finite element analysis) of the fracture callus material approach includes acquisition of microCT image volumes, biomechanical testing, finite element mesh
John, Volker
48 2 Functional Analysis for Linear Saddle Point Problems 2.4 Examples of Pairs of Finite Element Spaces Violating the Discrete Inf-Sup Condition Remark 2.50. On simple pairs of finite element spaces. The simplest and most common finite element spaces are spaces of continuous functions which are piecewise
Collins, Gary S.
Finite Element Analysis of Spherical Indentation Tests John Homans1, Sinisa Dj. Mesarovic2, Harish finite element analysis program Abaqus 6.7. · Runs were repeated using a dense mesh to ensure accuracy not influence the solution. Objective · Develop a finite element model to analyze: i) Load-depth response
GEO+, a finite element program on a personal computer
Guillin, Clement Gerard
1993-01-01T23:59:59.000Z
and BW' is the difference between the largest and smallest node numbers for an element e. If it, i2, i3, and i4 are the node numbers of a 4- noded quadrilateral element e, the maximum element node number difference BWe is given by: BW'=Max( [ii...-is[, [i2-i3[, [i3-i4[, [i4-ii[, [i3-ii[, [i2-i4[) (84) One way to minimize the bandwidth is to number the nodes such that BWe is as small as possible in each element, and thereby keep the numbers of each element as close as possible. This property...
Evaluation of the matrix exponential function using finite elements in time
Gebremedhin, D H; Zhang, X; Wynn, A; Tanaka, G
2008-01-01T23:59:59.000Z
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.
Evaluation of the matrix exponential function using finite elements in time
D H Gebremedhin; C A Weatherford; X Zhang; A Wynn III; G Tanaka
2008-11-17T23:59:59.000Z
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.
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES
Bartels, Soeren
NUMERICAL ANALYSIS OF A FINITE ELEMENT SCHEME FOR THE APPROXIMATION OF HARMONIC MAPS INTO SURFACES Geometric partial differential equations and their analysis as well as numerical simulation have recently
Bateman, Robert D
2011-01-01T23:59:59.000Z
Finite element analysis is a vastly expanding field which provides engineers a viable instrumentation to model and measure idealized constitutive stress strain relationships for various complex physical bodies. In the field ...
Design of a tricycle chassis using computer-aided design and finite element analysis
Avila, Elliot
2014-01-01T23:59:59.000Z
Finite element analysis and computer-aided design are powerful tools for modeling complex systems and their responses to external stimuli. This paper explores how these techniques were employed in a highly iterative design ...
TEA - a linear frequency domain finite element model for tidal embayment analysis
Westerink, Joannes J.
1984-01-01T23:59:59.000Z
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 ...
Jackson, Jason R.
1996-01-01T23:59:59.000Z
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...
Finite element analysis of elastic interaction of two en echelon overlapping faults
Leem, Junghun
1995-01-01T23:59:59.000Z
on the faults. Attention is focuses on the role of variable fault spacing and overlap for constant far-field compressive principal stresses. The linear elastic, isotropic, plane strain, finite element analyses are obtained. The basic modeling approach...
Bangerth, Wolfgang
Experimental Fluorescence Optical Tomography using Adaptive Finite Elements and Planar Illumination with Modulated Excitation Light Amit Joshia , Wolfgang Bangerthb , Alan B. Thompsona , and Eva M. Sevick adaptive discretization strategies. To date, the efficacy of adaptive mesh refinement techniques has yet
Least squares based finite element formulations and their applications in fluid mechanics
Prabhakar, Vivek
2009-05-15T23:59:59.000Z
In this research, least-squares based finite element formulations and their applications in fluid mechanics are presented. Least-squares formulations offer several computational and theoretical advantages for Newtonian as well as non-Newtonian fluid...
Ionic Polymer-Metal Composites: Thermodynamical Modeling and Finite Element Solution
Arumugam, Jayavel
2012-10-19T23:59:59.000Z
cantilever beams involving pure bending which could be used in the characterization of the material parameters. A linear finite element solution along with a staggered time stepping algorithm is provided to numerically solve the governing equations...
A mixed-dimensional finite volume method for multiphase flow
Cirpka, Olaf Arie
; Numerical reservoir simulation; Fractured reser- voir; Mixed-dimensional Finite Volume Method; MultigridA mixed-dimensional finite volume method for multiphase flow in fractured porous media Volker method for the fully coupled, fully implicit discretization of two-phase flow in fractured porous media
A finite element model of the quasi-three-dimensional viscous flow through airfoil cascades
McArthur, Dwight Roger
1987-01-01T23:59:59.000Z
by Orthogonal Collocation, " Chemical Engineering Science, Vol. 22, 1967, pp. 1483-1501. [15] Cook, R. D. , Concepts and Apphcations of the Finite Element Analysis. New York: John Wiley and Sons, 1981. [16] Hood, P. snd Taylor, C. , "Navier ? Stokes...A FINITE ELEMENT MODEL OF THE QUASI-THREE ? DIMENSIONAL VISCOUS FLOW THROUGH AIRFOIL CASCADES A Thesis by DWIGHT ROGER MCARTHUR Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree...
Finite element analysis of conjugate heat transfer in axisymmetric pipe flows
Fithen, Robert Miller
1987-01-01T23:59:59.000Z
FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MA STER... OF S CI EN CE August 1987 Major Subject: Mechanical Engineering FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Approved ss to style and content by: N. K. Anand (Chairman of Committee...
Spectral element methods for elliptic problems in nonsmooth domains
Pathria, D.; Karniadakis, G.E. [Brown Univ., Providence, RI (United States)] [Brown Univ., Providence, RI (United States)
1995-11-01T23:59:59.000Z
Engineering applications frequently require the numerical solution of elliptic boundary value problems in irregularly shaped domains. For smooth problems spectral element methods have proved very successful, since they can accommodate fairly complicated geometries while retaining a rapid rate of convergence. Geometric singularities, however, often give rise to singular solutions. The accuracy of the spectral element methods is then degraded, and they offer no apparent advantage over low-order finite element methods. In many cases, however, the singular structure of the solution is known, and its form may be exploited by the spectral element method. Among the various ways of doing so (through supplementary basis functions, eigenfunction expansions, and graded meshes), the method of auxiliary mapping proves to be particularly effective. For certain simple cases, the problem is transformed to a coordinate system in which the solution is analytic, and exponential convergence is recovered. Even when this is not possible, the singularity is usually much weaker after mapping, so that other treatments are more effective in the new coordinate system. In this paper, the authors study different ways of treating singularities, and in particular, the method of auxiliary mapping coupled with the use of supplementary basis functions. Error estimates are presented explaining why the combined approach is more effective, and these estimates are confirmed through a number of numerical experiments for the Laplace. Poisson, and Helmholtz equations. 28 refs., 13 figs., 5 tabs.
David L. Meier
1998-11-10T23:59:59.000Z
A new field of numerical astrophysics is introduced which addresses the solution of large, multidimensional structural or slowly-evolving problems (rotating stars, interacting binaries, thick advective accretion disks, four dimensional spacetimes, etc.). The technique employed is the Finite Element Method (FEM), commonly used to solve engineering structural problems. The approach developed herein has the following key features: 1. The computational mesh can extend into the time dimension, as well as space, perhaps only a few cells, or throughout spacetime. 2. Virtually all equations describing the astrophysics of continuous media, including the field equations, can be written in a compact form similar to that routinely solved by most engineering finite element codes. 3. The transformations that occur naturally in the four-dimensional FEM possess both coordinate and boost features, such that (a) although the computational mesh may have a complex, non-analytic, curvilinear structure, the physical equations still can be written in a simple coordinate system independent of the mesh geometry. (b) if the mesh has a complex flow velocity with respect to coordinate space, the transformations will form the proper arbitrary Lagrangian- Eulerian advective derivatives automatically. 4. The complex difference equations on the arbitrary curvilinear grid are generated automatically from encoded differential equations. This first paper concentrates on developing a robust and widely-applicable set of techniques using the nonlinear FEM and presents some examples.
Structural Mechanics & Solid Mechanics A finite element toolbox to MATLAB
Ehrhardt, Matthias
Structural Mechanics & Solid Mechanics Department of Mechanics and Materials CALFEM A finite.3 Copyright Â© 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
A. Yazdani; V. Nassehi
2011-01-10T23:59:59.000Z
This paper presents an optimum technique based on the least squares method for the derivation of the bubble functions to enrich the standard linear finite elements employed in the formulation of Galerkin weighted-residual statements. The element-level linear shape functions are enhanced with supplementary polynomial bubble functions with undetermined coefficients. The best least squares minimization of the residual functional obtained from the insertion of these trial functions into model equations results in an algebraic system of equations whose solution provides the unknown coefficients in terms of element-level nodal values. The normal finite element procedures for the construction of stiffness matrices may then be followed with no extra degree of freedom incurred as a result of such enrichment. The performance of the proposed method has been tested on a number of benchmark linear transport equations with the results compared against the exact and standard linear element solutions. It has been observed that low order bubble enriched elements produce more accurate approximations than the standard linear elements with no extra computational cost despite employing relatively crude mesh. However, for the solution of strongly convection or reaction dominated problems significantly higher order enrichments as well as extra mesh refinements will be required.
A mixed-dimensional finite volume method for two-phase flow in fractured porous media
Bastian, Peter
. Key words: Multiphase flow; Numerical reservoir simulation; Fractured reservoir; MixedA mixed-dimensional finite volume method for two-phase flow in fractured porous media Volker-phase flow in fractured porous media. Fractures are dis- cretely modeled as lower dimensional elements
Finite Element Simulation of Nonlinear Elastic Dynamics Using Cuda
California at Berkeley, University of
and e elements · A time-varying vector q(t) R3n which describes the displacement of the nodes positive definite linear system involving fext, fext, and M We focus on step 1 in this projectForce 8800 GT with 512 MB of memory. · Only uses single precision floating-point. GPUs with double
Numerical computation of constant mean curvature surfaces using finite elements
Jan Metzger
2004-08-18T23:59:59.000Z
This paper presents a method for computing two-dimensional constant mean curvature surfaces. The method in question uses the variational aspect of the problem to implement an efficient algorithm. In principle it is a flow like method in that it is linked to the gradient flow for the area functional, which gives reliable convergence properties. In the background a preconditioned conjugate gradient method works, that gives the speed of a direct elliptic multigrid method.
McArthur, Karl Edward
1996-01-01T23:59:59.000Z
, and hydraulic structures. The results of the SW=D model were compared to results from an application of the TXBLEND model by Texas Water Development Board to the same part of the estuary. TXBLEND is a two-dimensional hydrodynamic model based on the finite...
century as in the 19th century. In this paper I use finite element analysis to address the question, how element analysis Tom Parsons U.S. Geological Survey, Menlo Park, California, USA Received 23 August 2001 area seismic hazard assessment. This study presents a three-dimensional (3-D) finite element simulation
Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur
Ascenzi, Maria-Grazia, E-mail: mgascenzi@mednet.ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States)] [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Kawas, Neal P., E-mail: nealkawas@ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Lutz, Andre, E-mail: andre.lutz@hotmail.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Kardas, Dieter, E-mail: kardas@ibnm.uni-hannover.de [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany)] [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany); Nackenhorst, Udo, E-mail: nackenhorst@ibnm.uni-hannover.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Keyak, Joyce H., E-mail: jhkeyak@uci.edu [Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697-5000 (United States)
2013-07-01T23:59:59.000Z
We present an innovative method to perform multi-scale finite element analyses of the cortical component of the femur using the individual’s (1) computed tomography scan; and (2) a bone specimen obtained in conjunction with orthopedic surgery. The method enables study of micro-structural characteristics regulating strains and stresses under physiological loading conditions. The analysis of the micro-structural scenarios that cause variation of strain and stress is the first step in understanding the elevated strains and stresses in bone tissue, which are indicative of higher likelihood of micro-crack formation in bone, implicated in consequent remodeling or macroscopic bone fracture. Evidence that micro-structure varies with clinical history and contributes in significant, but poorly understood, ways to bone function, motivates the method’s development, as does need for software tools to investigate relationships between macroscopic loading and micro-structure. Three applications – varying region of interest, bone mineral density, and orientation of collagen type I, illustrate the method. We show, in comparison between physiological loading and simple compression of a patient’s femur, that strains computed at the multi-scale model’s micro-level: (i) differ; and (ii) depend on local collagen-apatite orientation and degree of calcification. Our findings confirm the strain concentration role of osteocyte lacunae, important for mechano-transduction. We hypothesize occurrence of micro-crack formation, leading either to remodeling or macroscopic fracture, when the computed strains exceed the elastic range observed in micro-structural testing.
Determining matrix elements and resonance widths from finite volume: the dangerous mu-terms
G. Takacs
2011-10-10T23:59:59.000Z
The standard numerical approach to determining matrix elements of local operators and width of resonances uses the finite volume dependence of energy levels and matrix elements. Finite size corrections that decay exponentially in the volume are usually neglected or taken into account using perturbation expansion in effective field theory. Using two-dimensional sine-Gordon field theory as "toy model" it is shown that some exponential finite size effects could be much larger than previously thought, potentially spoiling the determination of matrix elements in frameworks such as lattice QCD. The particular class of finite size corrections considered here are mu-terms arising from bound state poles in the scattering amplitudes. In sine-Gordon model, these can be explicitly evaluated and shown to explain the observed discrepancies to high precision. It is argued that the effects observed are not special to the two-dimensional setting, but rather depend on general field theoretic features that are common with models relevant for particle physics. It is important to understand these finite size corrections as they present a potentially dangerous source of systematic errors for the determination of matrix elements and resonance widths.
Li, H.; Li, G., E-mail: gli@clemson.edu [College of Engineering and Science, Clemson University, Clemson, South Carolina 29634-0921 (United States)
2014-08-28T23:59:59.000Z
An accelerated Finite Element Contact Block Reduction (FECBR) approach is presented for computational analysis of ballistic transport in nanoscale electronic devices with arbitrary geometry and unstructured mesh. Finite element formulation is developed for the theoretical CBR/Poisson model. The FECBR approach is accelerated through eigen-pair reduction, lead mode space projection, and component mode synthesis techniques. The accelerated FECBR is applied to perform quantum mechanical ballistic transport analysis of a DG-MOSFET with taper-shaped extensions and a DG-MOSFET with Si/SiO{sub 2} interface roughness. The computed electrical transport properties of the devices obtained from the accelerated FECBR approach and associated computational cost as a function of system degrees of freedom are compared with those obtained from the original CBR and direct inversion methods. The performance of the accelerated FECBR in both its accuracy and efficiency is demonstrated.
Yeh, G.T.
1982-10-01T23:59:59.000Z
This report documents a training course conducted for the US Nuclear Regulatory Commission (NRC) on the implementation of a Finite Element Model of WASTE transport through saturated-unsaturated porous media (FEMWASTE) - ORNL-5601. In addition to presenting basic program operations (Appendices A-V through A-VII), the course also covers the following topics: (1) Heuristic derivation of governing equations based on physical and chemical principles, (2) finite element derivation of FEMWASTE, (3) various numerical schemes provided by FEMWASTE, (4) FEMWASTE program structure, and (5) running of three samples problems to demonstrate various options the FEMWASTE can handle. The purpose of the training seminar is to enable NRC staff to use the model (and to be able to modify the code, if necessary) for checking information provided by a licensee, for evaluating alternative sites and designs for burial, and for comparing their results from other methods of solution.
Vaziri, Ashkan
Finite element analysis and computed tomography based structural rigidity analysis of rat tibia) (Damron et al., 2003; Mirels, 1989). In contrast, Computed Tomography based Structural Rigidly Ana- lysis
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
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...
Notes 12. Finite element modeling of mechanical systems
San Andres, Luis
2008-01-01T23:59:59.000Z
Engineering calculations on PC's are undergoing a revolution with the advent of spreadsheet programs. The author has found that virtually all of the energy analysis types of programs can be cast into spreadsheet methods ...
Varghese, Julian
2010-10-12T23:59:59.000Z
Figure 6.1: Predicted oxidation layer growth in neat PMR-15 resin .............. 141 Figure 6.2: Concentration profiles for oxidation and diffusion models. ........ 142 xii Page Figure 6.3: Effect of element size on oxidation layer... Table 5.1: Material Properties used in DCB finite element model ................ 121 Table 6.1: Oxidation material properties for neat PMR-15 resin ................... 140 Table 7.1: Oxidation material properties for the homogenized tows...
The Matrix Element Method and QCD Radiation
J. Alwall; A. Freitas; O. Mattelaer
2011-04-22T23:59:59.000Z
The matrix element method (MEM) has been extensively used for the analysis of top-quark and W-boson physics at the Tevatron, but in general without dedicated treatment of initial state QCD radiation. At the LHC, the increased center of mass energy leads to a significant increase in the amount of QCD radiation, which makes it mandatory to carefully account for its effects. We here present several methods for inclusion of QCD radiation effects in the MEM, and apply them to mass determination in the presence of multiple invisible particles in the final state. We demonstrate significantly improved results compared to the standard treatment.
Iterative solutions to large sparse finite element equations
Wang, Hongbing
1995-01-01T23:59:59.000Z
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...
NONCONFORMING FINITE ELEMENTS FOR REISSNER-MINDLIN PLATES
Lovadina, Carlo
to the more complex (and more inter- esting) case of shell problems. Indeed, the methods we will consider take.e. rotations and deflections) share the same nodes and degrees of freedom. The paper is organized as follows the transversal displacement, the scaled shear stresses and g a given transversal load. Finally, is the usual
Alternative Least-Squares Finite Element Models of Navier-Stokes Equations for Power-Law Fluids
Vallala, Venkat
2010-01-16T23:59:59.000Z
-Squares formulations of the original partial differential equations (PDE's) in terms of primary variables require C1 continuity of the finite element spaces across inter-element boundaries. This higherorder continuity requirement for PDE's in primary variables is a...
FINITE ELEMENT MODEL-BASED STRUCTURAL HEALTH MONITORING (SHM) SYSTEMS FOR COMPOSITE MATERIAL UNDER
Paris-Sud XI, Université de
FINITE ELEMENT MODEL-BASED STRUCTURAL HEALTH MONITORING (SHM) SYSTEMS FOR COMPOSITE MATERIAL UNDER). To design a Structural Health Monitoring (SHM) system, it is important to understand phenomenologically Workshop on Structural Health Monitoring July 8-11, 2014. La Cité, Nantes, France Copyright © Inria (2014
FAST AND ACCURATE FINITE ELEMENT APPROXIMATION OF WAVE MAPS INTO SPHERES
. The scheme has a second order consistency property and is energy preserving and reversible. Its unconditional show in this article that a similar strategy can be applied for finite element discretizations this first-order system in time according to dtuk+1 = uk+1/2 × wk+1/2 , dtwk+1 = uk+1/2 × uk+1/2 , where dt
Beaumont, Christopher
1 Salt tectonics driven by differential sediment loading: Stability analysis and finite element University of Leeds Leeds LS2 9JT United Kingdom e-mail: lykke@earth.leeds.ac.uk Short running title: Salt salt layer drives salt deformation and has a significant impact on the structural evolution
Finite Element Solution of Optimal Control Problems Arising in Semiconductor Modeling
Siefert, Chris
- timization problem, especially for highly heterogeneous materials with large jumps in material properties. 1Finite Element Solution of Optimal Control Problems Arising in Semiconductor Modeling Pavel Bochev, and inverse problems arising in the modeling of semiconductor devices lead to optimization problems
Simulation of Lung Behaviour with Finite Elements : Inuence of Bio-Mechanical Parameters
Paris-Sud XI, Université de
Simulation of Lung Behaviour with Finite Elements : Inuence of Bio-Mechanical Parameters Pierre by medical needs, we propose to simu- late lung deformation and motion during respiration to track tumours. This paper presents a model of lung behaviour based on a continuous media mechan- ics model and solved
Fleming, Andrew J.
and imperfections during the manufactur- ing process of the tube on the dynamics-coupling-caused errors in openSimulation of dynamics-coupling in piezoelectric tube scanners by reduced order finite element as the compensation of dynamics-coupling effects. The present article gives a detailed description of the fully
On a tensor-based finite element model for the analysis of shell structures
Arciniega Aleman, Roman Augusto
2006-04-12T23:59:59.000Z
In the present study, we propose a computational model for the linear and nonlinear analysis of shell structures. We consider a tensor-based finite element formulation which describes the mathematical shell model in a natural and simple way by using...
TIME DOMAIN ELECTROMAGNETIC SCATTERING USING FINITE ELEMENTS AND PERFECTLY MATCHED LAYERS
TIME DOMAIN ELECTROMAGNETIC SCATTERING USING FINITE ELEMENTS AND PERFECTLY MATCHED LAYERS H. T medium by a nonharmonic microwave pulse from an antenna source in free space, and we compute of the electromagnetic interrogation problems introduced in [3]. Here we use perfectly matched layers (PMLs) as absorbing
TIME DOMAIN ELECTROMAGNETIC SCATTERING USING FINITE ELEMENTS AND PERFECTLY MATCHED LAYERS
TIME DOMAIN ELECTROMAGNETIC SCATTERING USING FINITE ELEMENTS AND PERFECTLY MATCHED LAYERS H. T medium by a non-harmonic microwave pulse from an antenna source in free space, and we compute-dimensional version of the electromagnetic interrogation problems introduced in [3]. Here we use perfectly matched
Wadley, Haydn
The impact of sand slugs against beams and plates: Coupled discrete particle/finite element/continuum coupling Dynamic loading a b s t r a c t The impact of a slug of dry sand particles against a metallic for shock mitigation. The sand particles interact via a combined linear-spring-and-dashpot law whereas
Finite-element modeling of subglacial cavities and related friction law
Gagliardini, Olivier
Finite-element modeling of subglacial cavities and related friction law O. Gagliardini,1 D. Cohen,2, the friction law, can be easily extended from linear to nonlinear ice rheology and is bounded even for bedrocks with locally infinite slopes. Combining our results with earlier works by others, a phenomenological friction
An Online Data Access System for a Finite Element Program , David Liu2
Stanford University
management in FEA programs still mainly rely on file systems. The prevailing data structures are based of the problems encountered by the prevailing data management based on file systems. Current trend sees retrieval. The online data access system gives great flexibility to the management of data in finite element
A mixed finite-element scheme of a semiconductor energy-transport model
Hanke-Bourgeois, Martin
A mixed finite-element scheme of a semiconductor energy-transport model using dual entropy which are able to deal with physical effects such as carrier heating and velocity overshoot. The energy that the Joule heating term vanishes if the dual entropy variables w1 = (Âµ - V )/T and w2 = -1/T are employed
FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE FREQUENCIES
De Flaviis, Franco
#12;FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE@uci.edu The recent developments of microelectromechanical systems (MEMS) switch and their use at microwave frequencies have promoted exciting advancements in the field of microwave switching. In comparison with other
Barber, James R.
Elsevier B.V. All rights reserved. 1. Introduction The contact pressure between two sliding bodiesFinite element implementation of an eigenfunction solution for the contact pressure variation due is influenced by the profile of the bodies, but this is altered by wear so that the pressure distribution
Solid-mechanics finite element simulations of the draping of fabrics: a sensitivity analysis
Frey, Pascal
Solid-mechanics finite element simulations of the draping of fabrics: a sensitivity analysis L. Dong, C. Lekakou*, M.G. Bader School of Mechanical and Materials Engineering, University of Surrey into a "hat" shape, combining a hemispherical cup with a wide flat rim. A mechanical approach is adopted using
Mortar finite element discretization of a model coupling Darcy and Stokes equations
Boyer, Edmond
Mortar finite element discretization of a model coupling Darcy and Stokes equations by C. Bernardi1 flowing on a homogeneous porous ground, we consider a system where the Darcy and Stokes equations´erons un syst`eme o`u les ´equations de Darcy et de Stokes sont coupl´ees par des conditions de raccord
Mortar finite element discretization of the time dependent nonlinear Darcy's equations
Paris-Sud XI, Université de
Mortar finite element discretization of the time dependent nonlinear Darcy's equations by Karima variations have been handled in [1] and [6], while time-dependent Darcy's equations have been studied in [5 equations model the flow in a porous medium, but underground porous media are most often nonhomogeneous
A POSTERIORI ERROR ESTIMATE FOR THE H(div) CONFORMING MIXED FINITE ELEMENT FOR THE COUPLED
Wang, Yanqiu
for the Darcy equation, and vice versa. Special techniques usually need to be employed. In [3], a conformingA POSTERIORI ERROR ESTIMATE FOR THE H(div) CONFORMING MIXED FINITE ELEMENT FOR THE COUPLED DARCY pro- posed for the coupled Darcy-Stokes flow in [30], which imposes normal con- tinuity
Hybrid spectral/finite element analysis of dynamic delamination of patterned thin films
Sottos, Nancy R.
Hybrid spectral/finite element analysis of dynamic delamination of patterned thin films Phuong Tran Accepted 10 March 2008 Available online 20 March 2008 Keywords: Thin film Adhesion Delamination Dynamic analysis is performed to investigate the dynamic edge delamination of patterned thin films from a substrate
Adaptive Finite Element Discretization of Flow Problems for Goal-Oriented Model Reduction
. The emphasis is on laminar viscous incompressible flows governed by the Navier-Stokes equations. But also computation in a laminar viscous fluid modeled by the sta- tionary Navier-Stokes equations for velocity vAdaptive Finite Element Discretization of Flow Problems for Goal-Oriented Model Reduction Rolf
Thermo-elasto-plastic finite element analysis of quasi-state processes in Eulerian reference
Michaleris, Panagiotis
Thermo-elasto-plastic finite element analysis of quasi-state processes in Eulerian reference frames Incremental scheme Fine mesh along entire heat source path Lengthy computer runs · Elasto-Plasticity at times ti and ti-1, respectively. Penn State University 5 #12;Elasto-Plasticity Equilibrium: r(r, t) + b
A Finite-Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2014-09-01T23:59:59.000Z
Herein, we present a coupled thermal-hydro-mechanical model for geological sequestration of carbon dioxide followed by the stress, deformation, and shear-slip failure analysis. This fully coupled model considers the geomechanical response, fluid flow, and thermal transport relevant to geological sequestration. Both analytical solutions and numerical approach via finite element model are introduced for solving the thermal-hydro-mechanical model. Analytical solutions for pressure, temperature, deformation, and stress field were obtained for a simplified typical geological sequestration scenario. The finite element model is more general and can be used for arbitrary geometry. It was built on an open-source finite element code, Elmer, and was designed to simulate the entire period of CO2 injection (up to decades) both stably and accurately—even for large time steps. The shear-slip failure analysis was implemented based on the numerical results from the finite element model. The analysis reveals the potential failure zone caused by the fluid injection and thermal effect. From the simulation results, the thermal effect is shown to enhance well injectivity, especially at the early time of the injection. However, it also causes some side effects, such as the appearance of a small failure zone in the caprock. The coupled thermal-hydro-mechanical model improves prediction of displacement, stress distribution, and potential failure zone compared to the model that neglects non-isothermal effects, especially in an area with high geothermal gradient.
On the validation of seismic imaging methods: Finite frequency or ray theory?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Maceira, Monica; Larmat, Carene; Porritt, Robert W.; Higdon, David M.; Rowe, Charlotte A.; Allen, Richard M.
2015-01-23T23:59:59.000Z
We investigate the merits of the more recently developed finite-frequency approach to tomography against the more traditional and approximate ray theoretical approach for state of the art seismic models developed for western North America. To this end, we employ the spectral element method to assess the agreement between observations on real data and measurements made on synthetic seismograms predicted by the models under consideration. We check for phase delay agreement as well as waveform cross-correlation values. Based on statistical analyses on S wave phase delay measurements, finite frequency shows an improvement over ray theory. Random sampling using cross-correlation values identifiesmore »regions where synthetic seismograms computed with ray theory and finite-frequency models differ the most. Our study suggests that finite-frequency approaches to seismic imaging exhibit measurable improvement for pronounced low-velocity anomalies such as mantle plumes.« less
Ghosh, Somnath
A size-dependent crystal plasticity finite-element model for creep and load shedding Abstract A rate-dependent anisotropic elastic-crystal plasticity based finite-element (FE) model with size in the crystal plasticity relations are expressed as HallPetch type relations, where the grain size, lath size
Fluorescence photon migration by the boundary element method
Fedele, Francesco [Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT 05405 (United States); Eppstein, Margaret J. [Department of Computer Science, University of Vermont, Burlington, VT 05405 (United States)]. E-mail: maggie.eppstein@uvm.edu; Laible, Jeffrey P. [Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT 05405 (United States); Godavarty, Anuradha [Photon Migration Laboratories, Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States); Sevick-Muraca, Eva M. [Photon Migration Laboratories, Department of Chemistry, Texas A and M University, College Station, TX 77842-3012 (United States)
2005-11-20T23:59:59.000Z
The use of the boundary element method (BEM) is explored as an alternative to the finite element method (FEM) solution methodology for the elliptic equations used to model the generation and transport of fluorescent light in highly scattering media, without the need for an internal volume mesh. The method is appropriate for domains where it is reasonable to assume the fluorescent properties are regionally homogeneous, such as when using highly specific molecularly targeted fluorescent contrast agents in biological tissues. In comparison to analytical results on a homogeneous sphere, BEM predictions of complex emission fluence are shown to be more accurate and stable than those of the FEM. Emission fluence predictions made with the BEM using a 708-node mesh, with roughly double the inter-node spacing of boundary nodes as in a 6956-node FEM mesh, match experimental frequency-domain fluorescence emission measurements acquired on a 1087 cm{sup 3} breast-mimicking phantom at least as well as those of the FEM, but require only 1/8 to 1/2 the computation time.
Percutaneous Mitral Valve Dilatation: Single Balloon versus Double Balloon - A Finite Element Study
Schievano, Silvia; Kunzelman, Karyn; Nicosia, Mark; Cochran, R. P.; Einstein, Daniel R.; Khambadkone, Sachin; Bonheoffer, Philipp
2009-01-01T23:59:59.000Z
Background: Percutaneous mitral valve (MV) dilatation is performed with either a single balloon (SB) or double balloon (DB) technique. The aim of this study was to compare the two balloon system results using the finite element (FE) method. Methods and Results: An established FE model of the MV was modified by fusing the MV leaflet edges at commissure level to simulate a stenotic valve (orifice area=180mm2). A FE model of a 30mm SB (low-pressure, elastomeric balloon) and an 18mm DB system (high-pressure, non-elastic balloon) was created. Both SB and DB simulations resulted in splitting of the commissures and subsequent stenosis dilatation (final MV area=610mm2 and 560mm2 respectively). Stresses induced by the two balloon systems varied across the valve. At the end of inflation, SB showed higher stresses in the central part of the leaflets and at the commissures compared to DB simulation, which demonstrated a more uniform stress distribution. The higher stresses in the SB analysis were due to the mismatch of the round balloon shape with the oval mitral orifice. The commissural split was not easily accomplished with the SB due to its high compliance. The high pressure applied to the DB guaranteed the commissural split even when high forces were required to break the commissure welds. Conclusions: The FE model demonstrated that MV dilatation can be accomplished by both SB and DB techniques. However, the DB method resulted in higher probability of splitting of the fused commissures and less damage caused to the MV leaflets by overstretching.
Three dimensional finite element analysis of the flow of polymer melts
Jimack, Peter
Three dimensional finite element analysis of the flow of polymer melts R. Tencheva , T. Goughb , O.G, LS2 9JT, UK. b School of Engineering, Design & Technology, University of Bradford, Bradford, BD7 1DP.g.harlen@leeds.ac.uk (O.G. Harlen), p.k.jimack@leeds.ac.uk (P.K. Jimack), h.klein@leeds.ac.uk (D.H. Klein), m
Oelgaard, Kristian B; Wells, G N
2009-07-20T23:59:59.000Z
Optimisations for quadrature representations of finite element tensors through automated code generation KRISTIAN B. ØLGAARD Faculty of Civil Engineering and Geosciences Delft University of Technology and GARTH N. WELLS Department of Engineering... differential equations while achieving optimal or near-optimal run time performance is a possibility offered by K.B. Ølgaard, Faculty of Civil Engineering and Geosciences, Delft University of Technology Stev- inweg 1, 2628 CN Delft, Netherlands. Email: k.b...
The inclusion of damage effects in an incremental finite element analysis of composite plates
Kilpatrick, Mark Christopher
1984-01-01T23:59:59.000Z
, boron, carbon, graphite) supported in polymeric matrices and later ln light weight metal matrices. (mme- diatelyo the analysis of fiber composites began. Analyses of Fiber composites are approached from the micro- or macro-mechanics view- point... for ihe degree of MASTER OF SCIENCE December 1984 Major Subject: Mechanical Engineering THE INCLUSION OF DAMAGE EFFECTS IN AN INCREMENTAL FINITE ELEMENT ANALYSIS OF COMPOSITE PLATES A Thesis by MARK CHRISTOPHER KILPATRICK Approved as to style...
A UNSTRUCTURED NODAL SPECTRAL-ELEMENT METHOD FOR ...
2012-01-17T23:59:59.000Z
[19] S. J. Sherwin and G. E. Karniadakis. A triangular spectral element method; applications to the incompressible Navier-Stokes equations. Comput. Methods ...
Peng, McKenna, Fenves, Law1 An Open Collaborative Model for Development of Finite Element Program
Stanford University
a reality. The open source software development process reflects a powerful global trend toward networked and engineers can easily incorporate new element technologies and solution strategies. The distributed element engineering analysis programs. In current engineering practice, finite element packages need to be able
A fabrication method for integrated filter elements with inductance cancellation
Perreault, David J.
This paper outlines a fabrication method for integrated filter elements. An integrated filter element is a three- (or more) terminal device comprising a capacitor and coupled air-core magnetic windings, in which the magnetic ...
A voxel-based finite element model for the prediction of bladder deformation
Chai Xiangfei; Herk, Marcel van; Hulshof, Maarten C. C. M.; Bel, Arjan [Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands); Radiation Oncology Department, Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands); Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands)
2012-01-15T23:59:59.000Z
Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classical FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity coefficient to manual contours and <0.02 cm difference in mean standard deviation of residual errors). The average equation solving time (without manual intervention) for the first two types of hexahedral meshes increased to 2.3 h and 2.6 h compared to the 1.1 h needed for the tetrahedral mesh, however, the low-resolution nonuniform hexahedral mesh dramatically decreased the equation solving time to 3 min without reducing accuracy. Conclusions: Voxel-based mesh generation allows fast, automatic, and robust creation of finite element bladder models directly from binary segmentation images without user intervention. Even the low-resolution voxel-based hexahedral mesh yields comparable accuracy in bladder shape prediction and more than 20 times faster in computational speed compared to the tetrahedral mesh. This approach makes it more feasible and accessible to apply FE method to model bladder deformation in adaptive radiotherapy.
Michaleris, Panagiotis
Thermo-elasto-plastic finite element analysis of quasi-state processes in Eulerian reference frames-state one way coupled thermo-elasto- plastic systems has been developed. The formulation is suitable
Hossain, Mohammad Kabir
1990-01-01T23:59:59.000Z
. The use of High Density Polyethylene (HDPE) flexible pipes as vertical manholes in landfills and waste containment units is the primary reason for this investigation. A plane strain finite element (FEM) program containing incremental construction..." with Test Loading: (a) Section View; (b) Finite Element Idealization; (c) Top View . Test Cylinder Wall Radial Deformation for Various Support and Loading Conditions; Curve-A: Solution by AXISCOMP; Curve-B: Load at 0. 1" from Pinned Support; Curve...
Parallel 3D Finite Element Numerical Modelling of DC Electron Guns
Prudencio, E.; Candel, A.; Ge, L.; Kabel, A.; Ko, K.; Lee, L.; Li, Z.; Ng, C.; Schussman, G.; /SLAC
2008-02-04T23:59:59.000Z
In this paper we present Gun3P, a parallel 3D finite element application that the Advanced Computations Department at the Stanford Linear Accelerator Center is developing for the analysis of beam formation in DC guns and beam transport in klystrons. Gun3P is targeted specially to complex geometries that cannot be described by 2D models and cannot be easily handled by finite difference discretizations. Its parallel capability allows simulations with more accuracy and less processing time than packages currently available. We present simulation results for the L-band Sheet Beam Klystron DC gun, in which case Gun3P is able to reduce simulation time from days to some hours.
Methods of exploring energy diffusion in lattices with finite temperature
Ping Hwang; Hong Zhao
2011-06-15T23:59:59.000Z
We discuss two methods for exploring energy diffusion in lattices with finite temperature in this paper. The first one is the energy-kick (EK) method. To apply this method, one adds an external energy kick to a particle in the lattice, and tracks its evolution by evolving the kicked system. The second one is the fluctuation-correlation (FC) method. The formula for calculating the probability density function (PDF) using the canonical ensemble is slightly revised and extended to the microcanonical ensemble. We show that the FC method has advantages over the EK method theoretically and technically. Theoretically, the PDF obtained by the FC method reveals the diffusion processes of the inner energy while the PDF obtained by the EK method represents that of the kick energy. The diffusion processes of the inner energy and the external energy added to the system, i.e., the kick energy, may be different quantitatively and even qualitatively depending on models. To show these facts, we study not only the equilibrium systems but also the stationary nonequilibrium systems. Examples showing that the inner energy and the kick energy may have different diffusion behavior are reported in both cases. The technical advantage enables us to study the long-time diffusion processes and thus avoids the finite-time effect.
FINITE ELEMENT METHODS FOR THE SIMULATION OF INCOMPRESSIBLE POWDER FLOW
Hron, Jaroslav
configurations are provided. PHYSICAL BACKGROUD 1. Mohr-Coulomb criterion for friction The Mohr theory suggests a frictional stress model must be taken into account. This can be done using plasticity and similar theories cannot accurately describe granular flow. It is assumed that the material is incompressible, dry
Accepted Manuscript A finite element method for viscous membranes
Buscaglia, Gustavo C.
´ifica, Brazil Abstract The simulation of biological interfaces at the Living Cell scale relies on mem- brane
Extended Finite Element Method for Fretting Fatigue Crack Propagation
Sukumar, N.
.D. Denia a , F.J. Fuenmayor a aDepartamento de Ingenier´ia Mec´anica y de Materiales Universidad Polit
An Abaqus implementation of the extended finite element method
Sukumar, N.
. Taranc´on a , F. J. Fuenmayor a aDepartamento de Ingenier´ia Mec´anica y de Materiales Universidad Polit
Experimental verification of finite element enhancement and MAC methods
Ibrahim, Syed Azman
1991-01-01T23:59:59.000Z
for Shaft and Pipe Model 57 12. Measured Natural Frequencies and Damping Factor for Both Models . . 70 13. MAC on FE Mode Shapes - Shaft Model 14. Expanded MAC on FE Mode Shapes ? Shaft Model . . 88 88 15. MAC on FE/Test Mode Shapes ? Shaft Model Data... . . 7. Deformation of Piping System for the Cryogenic Rig at 9. 4 Hertz . . 8. Translational Vibration of the Gear Coupling Rig at 17 Hertz 9. Angular Vibration of the Gear Coupling Rig at 33 Hertz . . . . . . . . 15 41 42 43 44 45 46 10...
Stochastic finite element methods for partial differential equations with
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect JournalPentoxide.Conference:in(C4H12N2)Cu2Cl6 (Journal(TechnicalplasmasConnectrandom
Curved finite elements by the method of initial strains
Leick, Roger Dale
1974-01-01T23:59:59.000Z
Bw) yz By Bz P (By Bz By Bz + By Bz/ Bx ~ Bw I/(Bu Bu Bv Bv Bw Bw) 'zx Bz+ Bx+P QBz Bx+ Bz Bx+ Bz Bx/ (3 I lj) For tais development e , c , and s are zero from the discrete zP yzl zx Kirchhoff hypothesis and hence need not be considered further... this research. Thanks is also expressed to the other two committee members who contributed to this thesis, Dr. W. E. Haisler and Dr. W. L. Perry. This research was supported by Sandia Corporation contract No. 829005. DEDICATION This thesis is dedicated...
Uncoupled thermoelastic structural response by the finite element method
Linn, William Ray
1982-01-01T23:59:59.000Z
partial spacial derivatives and repeated indices imply summation), (k T ) P T[1+ 5( 1 & )( ? )] QT where (3X+2u) o T 6 6 v e (3) The style and citations of this thesis follow that of the 1 t'16166'1MttdJ~Eg where km is the thermal conductivity... ? ) + h(T -T) + sa(T -T ) + Q on I) (5) 3 BT 3 BT 4 v 3x x Bx By y By a r with the specified boundary conditions, T=T onl' s 1 (6a) k ? f. . + k ? / + h(T -T) + so(T "-T ) 0 on T (6b) x Bx x . y 3y y a r 2 where P, c?, T and T are defined as before...
Revisiting stabilized finite element methods for the advectivediffusive equation
Masud, Arif
at Denver, P.O. Box 173364, Campus Box 170, Denver, CO 80217-3364, USA b Departamento de MecaÂ´nica de Fluidos, Centro PoliteÂ´cnico Superior, C/Maria de Luna 3, 50018 Zaragoza, Spain c Department of Civil
stabilized finite element methods for coupled geomechanics and ...
COUPLED GEOMECHANICS AND MULTIPHASE FLOW a dissertation submitted to the department of petroleum engineering and the committee on graduate ...
Convergence of goal-oriented adaptive finite element methods
Pollock, Sara
2012-01-01T23:59:59.000Z
v ? V T . w ? V T . The dual energy estimator is: ? T p (v, T ), v ? V T . The dual energy estimator is: ? T 2 , j (
A VECTOR FINITE ELEMENT TIME-DOMAIN METHOD FOR ...
SIAM (#1) 1035 2001 Apr 10 12:32:38
2001-08-14T23:59:59.000Z
Helmholtz equation exhibits pollution due to numerical dispersion. In our example, the waveguide is ten wavelengths long and, for large values of h/a, the phase ...
Introduction of Finite Element Methods for Maxwell's Equations
2011-08-22T23:59:59.000Z
... fast algorithms have transformed the methodology for scientific investigation and industrial ... Students are required to present course-related material in class.
Partially Penalized Immersed Finite Element Methods for Parabolic ...
2015-01-26T23:59:59.000Z
... values of the shape on that edge is determined by the geometrical and material configuration ...... Society for Industrial and Applied Mathematics (SIAM),.
Generalized spectral decomposition method for solving stochastic finite element equations
Paris-Sud XI, Université de
or stochastic bases, have been proposed in order to reduce these computational costs. Recently, a new ap- proach times and memory requirements. The reduction of these computational costs has now become a key question and the automatic construction of reduced bases. In this paper, the concept of GSD, initially introduced for a class
A DISCONTINUOUS FINITE ELEMENT METHOD FOR SOLVING A MULTIWELL PROBLEM
elasticity, shapememory alloys, materials science. AMS subject classifications. 49M07, 65K10, 65N30, 73C50 in the engineering community, along with the rise of `rational' materials as seen for instance in shapememory alloys is the simulation of austenitemartensite transformations for shapememory alloys, and we refer to the work of Ball
Bixler, N.E.
1985-08-01T23:59:59.000Z
NORIA is a finite element computer program that solves four nonlinear, parabolic, partial differential equations simultaneously. The four equations describe the transport of water, water vapor, air, and energy through partially saturated porous media. The numerical procedure uses the standard Galerkin finite element method to handle spatial discretization of two-dimensional domains with either planar symmetry or axisymmetry. Time integration is performed by a third-order predictor-corrector scheme that uses error estimates to automatically adjust time-step size so as to maintain uniform local time truncation error throughout the calculation. Thus, the user is not required to select time-step size except at the first time step. Nearly all material properties, such as permeability, can either be set to constant values or can be defined as functions of the dependent and independent variables by user-supplied subroutines. The gas phase is taken to be ideal. This report is intended primarily as a user`s manual but also includes discussions of the theory of two-phase transport in porous media and the numerical procedure used in NORIA. 33 refs., 10 figs., 1 tab.
Finite element analysis of surface-stress effects in the Si lattice-parameter measurement
Sasso, Carlo; Massa, Enrico; Mana, Giovanni; Kuetgens, Ulrich
2013-01-01T23:59:59.000Z
A stress exists in solids surfaces, similarly to liquids, also if the underlying bulk material is stress-free. This paper investigates the surface stress effect on the measured value of the Si lattice parameter used to determine the Avogadro constant by counting Si atoms. An elastic-film model has been used to provide a surface load in a finite element analysis of the lattice strain of the x-ray interferometer crystal used to measure the lattice parameter. Eventually, an experiment is proposed to work a lattice parameter measurement out so that there is a visible effect of the surface stress.
A finite element analysis of a silicon based double quantum dot structure
S. Rahman; J. Gorman; C. H. W. Barnes; D. A. Williams; H. P. Langtangen
2006-04-06T23:59:59.000Z
We present the results of a finite-element solution of the Laplace equation for the silicon-based trench-isolated double quantum-dot and the capacitively-coupled single-electron transistor device architecture. This system is a candidate for charge and spin-based quantum computation in the solid state, as demonstrated by recent coherent-charge oscillation experiments. Our key findings demonstrate control of the electric potential and electric field in the vicinity of the double quantum-dot by the electric potential applied to the in-plane gates. This constitutes a useful theoretical analysis of the silicon-based architecture for quantum information processing applications.
BHARDWAJ, MANLJ K.; REESE,GARTH M.; DRIESSEN,BRIAN; ALVIN,KENNETH F.; DAY,DAVID M.
2000-04-06T23:59:59.000Z
As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance.
A finite element model for transient thermal/structural analysis of large composite space structures
Lutz, James Delmar
1986-01-01T23:59:59.000Z
Composite Space Structures. (May 1986) James Delmar Lutz, B. S. , Texas A&M University Chairmen of Advisory Committee: Dr. David H. Allen Dr. Walter E. Haisler A finite element model is developed for predicting the transient thermal/structural response... of structures to be analyzed in order to simplify the heat load analysis. The first r estr iction applies to the geometry of struc- tures to be analyzed. An appropriate structure should be of open lattice-type construction and have highly repetitive...
Mourad, Hashem M [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Addessio, Francis L [Los Alamos National Laboratory
2010-12-16T23:59:59.000Z
An explicit finite element formulation, used to study the behavior and failure mechanisms of metallic materials under high strain rate loading, is presented. The formulation is based on the assumed-strain approach of Fish and Belytschko [1988], which allows localization bands to be embedded within an element, thereby alleviating mesh sensitivity and reducing the required computational effort. The behavior of the material outside localization bands (and of the virgin material prior to the onset of strain localization) is represented using a Gurson-type coupled plasticity-damage model based on the work of Johnson and Addessio [1988]. Assuming adiabatic conditions, the response of the localization band material is represented by a set of constitutive equations for large elasticviscoplastic deformations in metals at high strain rates and high homologous temperatures (see Brown et al. [1989]). Computational results are compared to experimental data for different metallic alloys to illustrate the advantages of the proposed modeling strategy.
Finite element analysis on the fracture of rubber toughened polymer blends
Wu, Y.; Mai, Y.W. [Univ. of Sydney, New South Wales (Australia); Wu, J. [Hong Kong Univ. of Science and Technology (Hong Kong)
1997-12-31T23:59:59.000Z
The effect of rubber particle volume fraction on the constitutive relation and fracture toughness of polymer blends was studied using elastic-plastic Finite Element Analysis (FEA). The effect of rubber particle cavitation on the stress-strain state at a crack tip was also investigated. Stress analysis reveals that because of the high rubber bulk modulus, the hydrostatic stress inside the rubber particle is close to that in the adjacent matrix material element. As a result, the rubber particle imposes a severe plastic constraint to the surrounding matrix and limits its plastic strain. Rubber particle cavitation can effectively release the constraint and enable large scale plastic strain to occur. Different failure criteria were used to determine the optimum rubber particle volume fraction for the polymer blends studied in this paper.
Parallel spectral-element direction splitting method for ...
2014-07-03T23:59:59.000Z
Jun 14, 2014 ... [10] George E. Karniadakis, Spencer J. Sherwin, Spectral/hp Element Methods for Computational Fluid Dynamics, Oxford University Press, ...
Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas
2014-04-23T23:59:59.000Z
Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate-type fuel for the U.S. high-performance research reactors. This work supports the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll separating forces and rolling defects. Simulations were performed using a finite-element model developed using the commercial code LS-Dyna. Simulations of the hot rolling of U-10Mo coupons encapsulated in low-carbon steel have been conducted following two different schedules. Model predictions of the roll-separation force and roll-pack thicknesses at different stages of the rolling process were compared with experimental measurements. This report discusses various attributes of the rolled coupons revealed by the model (e.g., dog-boning and thickness non-uniformity).
Automation of the matrix element reweighting method
P. Artoisenet; V. Lemaître; F. Maltoni; O. Mattelaer
2011-02-01T23:59:59.000Z
Matrix element reweighting is a powerful experimental technique widely employed to maximize the amount of information that can be extracted from a collider data set. We present a procedure that allows to automatically evaluate the weights for any process of interest in the standard model and beyond. Given the initial, intermediate and final state particles, and the transfer functions for the final physics objects, such as leptons, jets, missing transverse energy, our algorithm creates a phase-space mapping designed to efficiently perform the integration of the squared matrix element and the transfer functions. The implementation builds up on MadGraph, it is completely automatized and publicly available. A few sample applications are presented that show the capabilities of the code and illustrate the possibilities for new studies that such an approach opens up.
Grujicic, Mica
Finite element analysis of the effect of up-armouring on the off-road braking and sharp-mobility multi-purpose wheeled vehicle, off-road vehicle performance, finite element modelling and simulations revision for publication on 15 June 2009. DOI: 10.1243/09544070JAUTO1187 Abstract: A comprehensive finite
Validation of Finite-Element Models of Persistent-Current Effects in Nb3Sn Accelerator Magnets
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, X.; Ambrosio, G.; Chlachidze, G.; Collings, E. W.; Dietderich, D. R.; DiMarco, J.; Felice, H.; Ghosh, A. K.; Godeke, A.; Gourlay, S. A.; et al
2015-01-06T23:59:59.000Z
Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality degradation, in particular at low field where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb3Sn accelerator magnets. Here a finite-element method based on the measured strand magnetization is validated against three state-of-art Nb3Sn accelerator magnets featuring different subelement diameters, critical currents, magnet designsmore »and measurement temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent current effects is discussed. The performance, limitations and possible improvements of the approach are also discussed.« less
Method of holding optical elements without deformation during their fabrication
Hed, P. Paul (80 Milaw Ct., San Ramon, CA 94583)
1997-01-01T23:59:59.000Z
An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool.
Christian Kreuzer; Endre Süli
2015-03-18T23:59:59.000Z
We develop the a posteriori error analysis of finite element approximations of implicit power-law-like models for viscous incompressible fluids. The Cauchy stress and the symmetric part of the velocity gradient in the class of models under consideration are related by a, possibly multi--valued, maximal monotone $r$-graph, with $\\frac{2d}{d+1}finite element residual, as well as the local stability of the error bound. We then consider an adaptive finite element approximation of the problem, and, under suitable assumptions, we show the weak convergence of the adaptive algorithm to a weak solution of the boundary-value problem. The argument is based on a variety of weak compactness techniques, including Chacon's biting lemma and a finite element counterpart of the Acerbi--Fusco Lipschitz truncation of Sobolev functions, introduced by L. Diening, C. Kreuzer and E. S\\"uli [Finite element approximation of steady flows of incompressible fluids with implicit power-law-like rheology. SIAM J. Numer. Anal., 51(2), 984--1015].
Superconvergence of finite element approximations by a computer-based approach
Gangaraj, Srihari Kumar
1994-01-01T23:59:59.000Z
%-SUPERCONVERGENCE . . 5. 1 Preliminaries . . 5. 2 The method of freezing the periodicity 5. 3 Numerical studies of g%-superconvergence . 5. 4 Summary 74 74 79 84 192 CHAPTER VI SUMMARY OF CONCLUSIONS . 6. 1 Conclusions based on this study 6. 2 Directions... shown i? (. I) u it I& tl a?shin? cl& n&cn(s: (&I) The mesh- patch of 1?qu &drat i?l& ln& n(s sh&&n? i? (I&) (vith j la?slllon clem&&nts. 66 73 Figure Figure Figurc Figure Figure 5. 2. Method ol' I& ppzi?g thc pcl'lo&licijy: (a) A finit& elr?1...
Finite Element Modeling and Validation of Residual Stresses in 304 L Girth Welds
Dike, J.J.; Ortega, A.R.; Cadden, C.H.; Rangaswamy, P. Brown, D.
1998-06-01T23:59:59.000Z
Three dimensional finite element simulations of thermal and mechanical response of a 304 L stainless steel pipe subjected to a circumferential autogenous gas tungsten arc weld were used to predict residual stresses in the pipe. Energy is input into the thermal model using a volumetric heat source. Temperature histories from the thermal analysis are used as loads in the mechanical analyses. In the mechanical analyses, a state variable constitutive model was used to describe the material behavior. The model accounts for strain rate, temperature, and load path histories. The predicted stresses are compared with x-ray diffraction determinations of residual stress in the hoop and circumferential directions on the outside surface of the pipe. Calculated stress profiles fell within the measured data. Reasons for observed scatter in measured stresses are discussed.
Leng, Wei [Chinese Academy of Sciences; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University; Price, Stephen [Los Alamos National Laboratory; Ringler, Todd [Los Alamos National Laboratory,
2012-01-01T23:59:59.000Z
The numerical modeling of glacier and ice sheet evolution is a subject of growing interest, in part because of the potential for models to inform estimates of global sea level change. This paper focuses on the development of a numerical model that determines the velocity and pressure fields within an ice sheet. Our numerical model features a high-fidelity mathematical model involving the nonlinear Stokes system and combinations of no-sliding and sliding basal boundary conditions, high-order accurate finite element discretizations based on variable resolution grids, and highly scalable parallel solution strategies, all of which contribute to a numerical model that can achieve accurate velocity and pressure approximations in a highly efficient manner. We demonstrate the accuracy and efficiency of our model by analytical solution tests, established ice sheet benchmark experiments, and comparisons with other well-established ice sheet models.
Finite element residual stress analysis of induction heating bended ferritic steel piping
Kima, Jong Sung [Sunchon National University, 255 Jungang-ro, Sucheon, Jeonnam (Korea, Republic of); Kim, Kyoung-Soo; Oh, Young-Jin; Chang, Hyung-Young; Park, Heung-Bae [KEPCO E and C, Co., Ltd., 188, Kumi-ro, Seongnam, Kyounggi (Korea, Republic of)
2014-10-06T23:59:59.000Z
Recently, there is a trend to apply the piping bended by induction heating process to nuclear power plants. Residual stress can be generated due to thermo-mechanical mechanism during the induction heating bending process. It is well-known that the residual stress has important effect on crack initiation and growth. The previous studies have focused on the thickness variation. In part, some studies were performed for residual stress evaluation of the austenitic stainless steel piping bended by induction heating. It is difficult to find the residual stresses of the ferritic steel piping bended by the induction heating. The study assessed the residual stresses of induction heating bended ferriticsteel piping via finite element analysis. As a result, it was identified that high residual stresses are generated on local outersurface region of the induction heating bended ferritic piping.
Liu, Yijun
A fast multipole boundary element method for modeling 2-D multiple crack problems with constant 3 April 2014 Accepted 20 May 2014 Keywords: Fast multipole BEM 2-D multi-crack problems Constant elements Crack opening displacements Stress intensity factors a b s t r a c t A fast multipole boundary
Block-structured Adaptive Finite Volume Methods for Shock-Induced Combustion
Deiterding, Ralf
Block-structured Adaptive Finite Volume Methods for Shock-Induced Combustion Simulation Ralf-Induced Combustion Simulation 1 #12;Structure of the lectures Block-structured Adaptive Finite Volume Methods for Shock-Induced Combustion Simulation 2 #12;Structure of the lectures 1. Fundamentals of finite volume
Zocher, Marvin Anthony
1990-01-01T23:59:59.000Z
be used for predicting quasi-static crack growth in a class ol' nonlinear viscoelastic materials under finite strain. C'lassicu/ Plate Theory: Schapery and Davidson ' have used classical plate theory (C'PT) in predicting the energy release rate (ERR... plate, shell, or beam. . 1Icthod of C'elis: Aboudi has developed a. method for determination of the effec- tive moduli of infinite elastic solids containing a, doubly periodic rectangular array of cracks. It consists of the analysis of a, unit cell...
Resolution of grain scale interactions using the Discrete Element Method
Johnson, Scott M. (Scott Matthew), 1978-
2006-01-01T23:59:59.000Z
Granular materials are an integral part of many engineering systems. Currently, a popular tool for numerically investigating granular systems is the Discrete Element Method (DEM). Nearly all implementations of the DEM, ...
Methods and devices for fabricating and assembling printable semiconductor elements
Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao
2014-03-04T23:59:59.000Z
The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.
Methods and devices for fabricating and assembling printable semiconductor elements
Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao
2013-05-14T23:59:59.000Z
The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.
Methods and devices for fabricating and assembling printable semiconductor elements
Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Durham, NC); Lee, Keon Jae (Daejeon, KR); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Champaign, IL); Meitl, Matthew (Raleigh, NC); Zhu, Zhengtao (Urbana, IL)
2011-07-19T23:59:59.000Z
The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.
Methods and devices for fabricating and assembling printable semiconductor elements
Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Urbana, IL); Lee, Keon Jae (Savoy, IL); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Champaign, IL); Meitl, Matthew (Champaign, IL); Zhu, Zhengtao (Urbana, IL)
2009-11-24T23:59:59.000Z
The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.
E. Sun, P. Brindza, S. Lassiter, M. Fowler, E. Xu
2010-06-01T23:59:59.000Z
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.
A Layerwise Shell Stiffener and Stand-Alone Curved Beam Element
Kassegne, Samuel Kinde
for the analysis of stiffened plates and shells. The finite element method has been used by a number elements. The element can also be used as a stand-alone curved or straight beam element. A finite element and Schnobrich [1] proposed a sixteen degrees of freedom isotropic beam finite element which has a displacement
Payan, Yohan
/lower lip contacts are also modeled. Simulations of smiling and of an Orbicularis Oris activationAbstract: A 3D biomechanical finite element model of the face is presented. Muscles are represented the mesh or the muscle implementation totally independently of each other. Lip/teeth and upper lip
Ewing, Richard E.
A ThreeDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination for transport of nuclearwaste contamination in threedimensional porous media are presented with a description of contamination of groundwater by highlevel nuclear waste and a wide variety of other sources makes a proper
Lim, Jong Il
2007-04-25T23:59:59.000Z
Finite element analysis of electric double layer capacitors using a transient nonlinear Nernst-Planck-Poisson (NPP) model and Nernst-Planck-Poisson-modified Stern layer (NPPMS) model are presented in 1D and 2D. The NPP model provided unrealistic ion...
Lim, Jong Il
2007-04-25T23:59:59.000Z
Finite element analysis of electric double layer capacitors using a transient nonlinear Nernst-Planck-Poisson (NPP) model and Nernst-Planck-Poisson-modified Stern layer (NPPMS) model are presented in 1D and 2D. The NPP model provided unrealistic ion...
Oxley, Paul
Finite element solution of Laplace's equation for ion-atom chambers Jacob Golde, Janine Shertzer for ion-atom chambers. We first consider a simplified model chamber for which an analytical solution can is carried out in an ion-atom chamber. The atomic beam first passes through a region of the cham- ber where
Terzopoulos, Demetri
, PET and other noninvasive medical imaging technologies can provide exceptional views of internal elastically to t the image data. The tting process is mediated by internal forces stemming from the elastic tting process. Keywords: 3D/4D Medical Image Analysis, Deformable Models, Finite Elements, Dynamics
Patzek, Tadeusz W.
Finite Element Solution of Nonlinear Transient Rock Damage with Application in Geomechanics of Oil the geomechanics of oil and gas reservoirs. The fragile microstructure of some rocks makes it difficult to predict. The results could be used in similar geomechanical and structural damage problems such as failure and rupture
An implicit finite-element model for 3D non-hydrostatic mesoscale ocean M.A. Maidana1
Politècnica de Catalunya, Universitat
An implicit finite-element model for 3D non-hydrostatic mesoscale ocean flows M.A. Maidana1 , J-dimensional, non-hydrostatic mesoscale ocean flows. The model considered here incorporates surface wind stress and the idea of using unstructured grids for modelling mesoscale ocean dynamics sounds very attractive given
Agrawal, Ravi Prakash
2006-08-16T23:59:59.000Z
and locations of the stresses in RRPMs during the tire-marker impacts by doing the finite element modeling and simulation of the impacts, and use the information to recommend laboratory testing procedures that could simulate real-world conditions. The researcher...
Incorporation and modification of a shear deformable finite element into MARC
Hofman, Brad Burdell
1996-01-01T23:59:59.000Z
The proposed research focuses on implementing an existing shear deformable composite element as a user element in MARC[]. Furthermore, the element is enhanced by developing an algorithm to accommodate variable thickness within an element...
A Computational Study of Finitely Convergent Polyhedral Methods ...
2010-12-24T23:59:59.000Z
Dec 24, 2010 ... (2009) proposed a finite polyhedral characterization of the convex hull .... well as computational results using the same battery of test instances.
Method of holding optical elements without deformation during their fabrication
Hed, P.P.
1997-04-29T23:59:59.000Z
An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element is disclosed. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool. 16 figs.
Method and system for high power reflective optical elements
Demos, Stavros G.; Rubenchik, Alexander M.; Negres, Raluca A.
2013-03-12T23:59:59.000Z
A method of repairing damage in an optical element includes providing a laser system including at least one optical element having a coating layer having an incident light surface and directing a laser pulse from the laser system to impinge on the incident light surface. The method also includes sustaining damage to a portion of the incident light surface and melting the damaged portion of the incident light surface and a region adjacent to the damaged portion. The method further includes flowing material from the region adjacent the damaged portion to the damaged portion and solidifying the material in the damaged portion and the region adjacent to the damaged portion.
A MULTIPOLE BOUNDARY ELEMENT METHOD FOR TWO DIMENSIONAL ELASTOSTATICS 3
Yamamoto, Hirosuke
A MULTIPOLE BOUNDARY ELEMENT METHOD FOR TWO DIMENSIONAL ELASTOSTATICS 3 YOSIHIRO YAMADAy z AND KEN. To avoid these problems, Rokhlin proposed the multipole method for the potential prob- lem. This paper requires O(N log N) work and memory. Theoretical error estimates for the multipole expansions are also
Iskander, S.K.
1981-02-01T23:59:59.000Z
Two finite element (FE) approaches were used to calculate opening mode I stress intensity factors (K/sub I/) in two- or three-dimensional (2-D and 3-D) problems for the Heavy-Section Steel Technology (HSST) program. For problems that can be modeled in two dimensions, two techniques were used. One of these may be termed an ''energy release rate'' technique, and the other is based on the classical near-tip displacement and stress field equations. For three-dimensional problems, only the latter technique was used. In the energy release technique, K/sub I/ is calculated as the change in potential energy of the structure due to a small change in crack length. The potential energy is calculated by the FE method but without completely solving the system of linear equations for the displacements. Furthermore, the system of linear equations is only slightly perturbed by the change in crack length and, therefore, many computations need not be repeated for the second structure with the slight change in crack length. Implementation of these last two items has resulted in considerable savings in the calculation of K/sub I/ as compared to two complete FE analyses. These ideas are incorporated in the FMECH code. The accuracy of the methods has been checked by comparing the results of the two approaches with each other and with closed form solutions. It is estimated that the accuracy of the results is about +-5%.
Finite element modelling of shock-induced damages on ceramic hip prostheses
Uribe, Juliana; Geringer, Jean; 10.5402/2011/121486
2012-01-01T23:59:59.000Z
The aim of this work was to simulate the behaviour of hip prostheses under mechanical shocks. When hip joint is replaced by prosthesis, during the swing phase of the leg, a microseparation between the prosthetic head and the cup could occur. Two different sizes of femoral heads were studied: 28 and 32 mm diameter, made, respectively, in alumina and zirconia. The shock-induced stress was determined numerically using finite element analysis (FEA), Abaqus software. The influence of inclination, force, material, and microseparation was studied. In addition, an algorithm was developed from a probabilistic model, Todinov's approach, to predict lifetime of head and cup. Simulations showed maximum tensile stresses were reached on the cup's surfaces near to rim. The worst case was the cup-head mounted at 30^{\\circ}. All simulations and tests showed bulk zirconia had a greater resistance to shocks than bulk alumina. The probability of failure could be bigger than 0.9 when a porosity greater than 0.7% vol. is present in...
Combined simulation of whirl and stick-slip phenomena using a nonlinear finite element model
Schmalhorst, B. [Baker Hughes INTEQ GmbH, Celle (Germany); Baumgart, A. [Technical Univ. Braunschweig (Germany)
1997-07-01T23:59:59.000Z
A time domain drillstring dynamics model allows the prediction of BHA dynamics related to torsional and two plane lateral vibrations. The model considers a nonlinear Finite Element approach that takes into account arbitrarily shaped assemblies during drilling of curved boreholes. Each nodal point represents a stabilizer, a collar connection or a wear knot moving viscously dampled inside open hole or a casing. In the case of wall contact, restitution forces from the formation act on the string and contact velocity dependent friction forces are introduced. The torsional and the lateral degrees of freedom (d.o.f.) are therefore coupled. The authors introduce a nonlinear relationship between the cutting forces at the PDC bit and the angular velocity of the bit. Bit and BHA whirl, rotational Stick-Slip phenomena and normal drilling conditions are solved numerically. Results show that the drilling process is always transient. Commonly used static models only can provide the drilling engineer with rough estimates of the loading. Evaluation of BHA failures sometimes reveal an ultra high dynamic loading of the BHA components that can be analyzed and predicted with this time domain application.
Quinones, Armando, Sr. (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2008-08-01T23:59:59.000Z
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).
Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.
Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay
2012-01-01T23:59:59.000Z
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.
Martin, Ralph R.
Solving ODEs: Cardiac drug risk assessment The heat equation and finite elements: electrical;Solving ODEs: Cardiac drug risk assessment The heat equation and finite elements: electrical propagation in the heart Solving ODEs: Cardiac drug risk assessment #12;Solving ODEs: Cardiac drug risk assessment The heat
Collins, Gary S.
Discussion Data collected here will aid researchers in creating a more accurate crystal plasticity grant number DMR-1062898. Introduction Although various crystal plasticity finite element models (CPFEMs Â· Provide data for researchers to create crystal plasticity finite element models (CPFEM) that characterize
Direct Forcing Immersed Boundary Methods: Finite Element Versus Finite Volume Approach
Frisani, Angelo 1980-
2012-12-07T23:59:59.000Z
and first order accuracy in time are obtained when the Taylor-Green decaying vortex test case is compared to the IFVM analytical solution. Computations were performed using the IFEM and IFVM approaches for the two-dimensional flow over a backward...
A stochastic method for computing hadronic matrix elements
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Drach, Vincent; Jansen, Karl; Alexandrou, Constantia; Constantinou, Martha; Dinter, Simon; Hadjiyiannakou, Kyriakos; Renner, Dru B.
2014-01-22T23:59:59.000Z
We present a stochastic method for the calculation of baryon 3-point functions which is an alternative to the typically used sequential method offering more versatility. We analyze the scaling of the error of the stochastically evaluated 3-point function with the lattice volume and find a favorable signal to noise ratio suggesting that the stochastic method can be extended to large volumes providing an efficient approach to compute hadronic matrix elements and form factors.
A stochastic method for computing hadronic matrix elements
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Drach, Vincent [DESY, Zeuthen (Germany); Jansen, Karl [DESY, Zeuthen (Germany); Alexandrou, Constantia [University of Cyprus, Nicosia (Cyprus); Constantinou, Martha [University of Cyprus, Nicosia (Cyprus); Dinter, Simon [DESY, Zeuthen (Germany); Hadjiyiannakou, Kyriakos [University of Cyprus, Nicosia (Cyprus); Renner, Dru B. [JLAB, Newport News, VA (United States)
2014-01-01T23:59:59.000Z
We present a stochastic method for the calculation of baryon 3-point functions which is an alternative to the typically used sequential method offering more versatility. We analyze the scaling of the error of the stochastically evaluated 3-point function with the lattice volume and find a favorable signal to noise ratio suggesting that the stochastic method can be extended to large volumes providing an efficient approach to compute hadronic matrix elements and form factors.
Nuclear fuel elements and method of making same
Schweitzer, Donald G. (Bayport, NY)
1992-01-01T23:59:59.000Z
A nuclear fuel element for a high temperature gas nuclear reactor that has an average operating temperature in excess of 2000.degree. C., and a method of making such a fuel element. The fuel element is characterized by having fissionable fuel material localized and stabilized within pores of a carbon or graphite member by melting the fissionable material to cause it to chemically react with the carbon walls of the pores. The fissionable fuel material is further stabilized and localized within the pores of the graphite member by providing one or more coatings of pyrolytic carbon or diamond surrounding the porous graphite member so that each layer defines a successive barrier against migration of the fissionable fuel from the pores, and so that the outermost layer of pyrolytic carbon or diamond forms a barrier between the fissionable material and the moderating gases used in an associated high temperature gas reactor. The method of the invention provides for making such new elements either as generally spherically elements, or as flexible filaments, or as other relatively small-sized fuel elements that are particularly suited for use in high temperature gas reactors.
Hoffman, E.L.; Ammerman, D.J.
1993-08-01T23:59:59.000Z
A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several finite element simulations of the event. The purpose of the study is to compare the performance of the various analysis codes and element types with respect to a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry.
Reproducing kernel element method Part III: Generalized enrichment and applications
Li, Shaofan
Reproducing kernel element method Part III: Generalized enrichment and applications Hongsheng Lu enrichment is proposed to construct the global partition polynomials or to enrich global partition polynomial. This is accomplished by either multiplying enrichment functions with the original global partition poly- nomials
Finite element simulations of compositionally graded InGaN solar cells G.F. Brown a,b,n
Wu, Junqiao
, a highly conductive p-type GaN layer provides the hole contact while absorption takes place in the lowerFinite element simulations of compositionally graded InGaN solar cells G.F. Brown a,b,n , J.W. Ager Keywords: Device modeling InGaN Composition grading Heterojunction a b s t r a c t The solar power
Gardner, David [Lawrence Livermore National Laboratory (LLNL); Woodward, Carol S. [Lawrence Livermore National Laboratory (LLNL); Evans, Katherine J [ORNL
2015-01-01T23:59:59.000Z
Efficient solution of global climate models requires effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a time step dictated by accuracy of the processes of interest rather than by stability governed by the fastest of the time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton s method is applied for these systems. Each iteration of the Newton s method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite-difference which may show a loss of accuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite-difference approximations of these matrix-vector products for climate dynamics within the spectral-element based shallow-water dynamical-core of the Community Atmosphere Model (CAM).
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Woodward, Carol S.; Gardner, David J.; Evans, Katherine J.
2015-01-01T23:59:59.000Z
Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but thismore »Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.« less
Woodward, Carol S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gardner, David J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Evans, Katherine J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2015-01-01T23:59:59.000Z
Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.
Method and apparatus for diagnosing breached fuel elements
Gross, K.C.; Lambert, J.D.B.; Nomura, S.
1987-03-02T23:59:59.000Z
The invention provides an apparatus and method for diagnosing breached fuel elements in a nuclear reactor. A detection system measures the activity of isotopes from the cover gas in the reactor. A data acquisition and processing system monitors the detection system and corrects for the effects of the cover-gas clean up system on the measured activity and further calculates the derivative curve of the corrected activity as a function of time. A plotting system graphs the derivative curve, which represents the instantaneous release rate of fission gas from a breached fuel element. 8 figs.
Method and apparatus for diagnosing breached fuel elements
Gross, Kenny C. (Lemont, IL); Lambert, John D. B. (Wheston, IL); Nomura, Shigeo (Mito, JP)
1988-01-01T23:59:59.000Z
The invention provides an apparatus and method for diagnosing breached fuel elements in a nuclear reactor. A detection system measures the activity of isotopes from the cover-gas in the reactor. A data acquisition and processing system monitors the detection system and corrects for the effects of the cover-gas clean up system on the measured activity and further calculates the derivative cure of the corrected activity as a function of time. A plotting system graphs the derivative curve, which represents the instantaneous release rate of fission gas from a breached fuel element.
A posteriori error analysis for a finite volume method
Tavener, Simon
of nuclear fuel rods, electrical impedance tomography · Pose well known challenges for accurate numerical interface method · Fictitious domain method · Ghost fluid method · (Immersed boundary method
Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients
Kalchev, D
2012-04-02T23:59:59.000Z
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.
Unstructured spectral element methods of simulation of turbulent flows
Henderson, R.D. [California Inst. of Technology, Pasadena, CA (United States)] [California Inst. of Technology, Pasadena, CA (United States); Karniadakis, G.E. [Brown Univ., Providence, RI (United States)] [Brown Univ., Providence, RI (United States)
1995-12-01T23:59:59.000Z
In this paper we present a spectral element-Fourier algorithm for simulating incompressible turbulent flows in complex geometries using unstructured quadrilateral meshes. To this end, we compare two different interface formulations for extending the conforming spectral element method in order to allow for surgical mesh refinement and still retain spectral accuracy: the Zanolli iterative procedure and variational patching based on auxiliary {open_quotes}mortar{close_quotes} functions. We present an interpretation of the original mortar element method as a patching scheme and develop direct and iterative solution techniques that make the method efficient for simulations of turbulent flows. The properties of the new method are analyzed in detail by studying the eigenspectra of the advection and diffusion operators. We then present numerical results that illustrate the flexibility as well as the exponential convergence of the new algorithm for nonconforming discretizations. We conclude with simulation studies of the turbulent cylinder wake at Re = 1000 (external flow) and turbulent flow over riblets at Re = 3280 (internal flow). 36 refs., 29 figs., 7 tabs.
On simple and accurate finite element models for nonlinear bending analysis of beams and plates
Urthaler Lapeira, Yetzirah Yksya
2007-09-17T23:59:59.000Z
CR yˆ u1 u2 ?1 ? v1 ?2 v2 L Fig. 3. Kinematics of the corotational Euler-Bernoulli beam element 21 corotated coordinate system (^x; ^y) for the beam element is attached to the element and deflned so that the ^x axis remains coincident with a line...
Method for measuring recovery of catalytic elements from fuel cells
Shore, Lawrence (Edison, NJ); Matlin, Ramail (Berkeley, NJ)
2011-03-08T23:59:59.000Z
A method is provided for measuring the concentration of a catalytic clement in a fuel cell powder. The method includes depositing on a porous substrate at least one layer of a powder mixture comprising the fuel cell powder and an internal standard material, ablating a sample of the powder mixture using a laser, and vaporizing the sample using an inductively coupled plasma. A normalized concentration of catalytic element in the sample is determined by quantifying the intensity of a first signal correlated to the amount of catalytic element in the sample, quantifying the intensity of a second signal correlated to the amount of internal standard material in the sample, and using a ratio of the first signal intensity to the second signal intensity to cancel out the effects of sample size.
Method for detection of antibodies for metallic elements
Barrick, C.W.; Clarke, S.M.; Nordin, C.W.
1993-11-30T23:59:59.000Z
An apparatus and method for detecting antibodies specific to non-protein antigens. The apparatus is an immunological plate containing a plurality of plastic projections coated with a non-protein material. Assays utilizing the plate are capable of stabilizing the non-protein antigens with detection levels for antibodies specific to the antigens on a nanogram level. A screening assay with the apparatus allows for early detection of exposure to non-protein materials. Specifically metallic elements are detected. 10 figures.
in spirit to a mixed finite element method or a PetrovGalerkin scheme. If the sequence of orthogonal commonly used for finite element approximations [14]. The technique proceeds by integrating against ``testPetrovGalerkin Spectral Elements 1 A PetrovGalerkin Spectral Element Technique for Heterogeneous
Benchmark on Anisotropic Problems Numerical investigation of a mimetic finite difference method
Cirpka, Olaf Arie
Bernd Flemisch, Rainer Helmig Universität Stuttgart Institute of Hydraulic Engineering Department ourselves, we only provide a brief and rough overview in the following. For more details, we would like is given by Algorithm 1 in [BRE 05b]. By usual hybridization known from mixed finite elements, system [2
Lau, Ryan
2007-09-17T23:59:59.000Z
Relatively little is known about marine controlled-source electromagnetic surveys (MCSEM) used to detect hydrocarbon reservoirs. Typical MCSEM require the use of inversion to generate a model of the subsurface. We utilize a 3D finite-element forward...
Efficient numerical methods for capacitance extraction based on boundary element method
Yan, Shu
2006-04-12T23:59:59.000Z
algorithms based on boundary element methods (BEM) and to compute the capacitance extraction in the presence of floating dummy conductors. We propose the PHiCap algorithm, which is based on a hierarchical refinement algorithm and the wavelet transform. Unlike...
Superconvergence of finite element approximations by a computer-based approach
Gangaraj, Srihari Kumar
1994-01-01T23:59:59.000Z
. Superconvergence points "FI" l9u &3 u for (a) ? '; (b) ? '; (c) o?; (d) e, z 1 2 Figure 4. 5. &1%-superconvergence regions for the class of "harmonic" solutions of the equations of plane elasticity: Cubic serendipity square elements. The regions R&~' I('P "H... points for meshes of square elements. . . . . . . . . . . . . . . 4. 2. Superconvergence for meshes of square elements. Cubic elements, general solution (u (x?xs) = sin(llxl) sin(lrxz)): (3 X 3) Gauss- Legendre points. Values of the discrete...
Computational Solid Mechanics using a Vertex-based Finite Volume Method
Taylor, Gary
Computational Solid Mechanics using a Vertex-based Finite Volume Method G. A. Taylor, C. Bailey and using nite volume (FV) methods for computational solid mechanics (CSM). These methods are proving]. As a contemporary, the FV method has similarlyestablished itself within the eld of computational uid dynamics (CFD
A non-linear constrained optimization technique for the mimetic finite difference method
Manzini, Gianmarco [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Svyatskiy, Daniil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bertolazzi, Enrico [Univ. of Trento (Italy); Frego, Marco [Univ. of Trento (Italy)
2014-09-30T23:59:59.000Z
This is a strategy for the construction of monotone schemes in the framework of the mimetic finite difference method for the approximation of diffusion problems on unstructured polygonal and polyhedral meshes.
Parry, G. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex, (France)]. E-mail: guillaume.parry@etu.univ-poitiers.fr; Colin, J. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex (France); Coupeau, C. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex (France); Foucher, F. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex (France); Cimetiere, A. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex (France); Grilhe, J. [Laboratoire de Metallurgie Physique, UMR 6630, du CNRS, Universite de Poitiers, BP 30179, 86962 Futuroscope Cedex (France)
2005-01-10T23:59:59.000Z
The post-critical regime of straight-sided wrinkles on compliant substrates of polycarbonate has been observed by atomic force microscope and investigated by means of finite element simulations. The effect of coupling between the film and its substrate has revealed a global buckling phenomenon, characterized by critical loads lower than those found in the case of a rigid substrate. Characteristic shapes of the buckled structure have been also found to spread over a region wider than the delaminated zone itself. A law relating the film deflexion to the stress has finally been established for any film/substrate system.
Liu, Mian
How does trench coupling lead to mountain building in the Subandes? A viscoelastoplastic finite cause of the Andean mountain building. The present-day crustal shortening in the Andes is clear from the cyclic trench coupling leads to long-term mountain building, which has been concentrated in the Subandes
LOWER TRANSIENT STRESSES IN AN AORTIC VALVE LEAFLET WITH OBLIQUE REINFORCEMENT FIBERS: A FINITE Cambridge, MA, USA INTRODUCTION Native aortic valve leaflets contain a network of strong collagen fibers the stresses of cyclic loading over billions of heart beats. Replacement valves that consist of animal tissues
The Matrix Element Method: Past, Present, and Future
James S. Gainer; Joseph Lykken; Konstantin T. Matchev; Stephen Mrenna; Myeonghun Park
2013-07-26T23:59:59.000Z
The increasing use of multivariate methods, and in particular the Matrix Element Method (MEM), represents a revolution in experimental particle physics. With continued exponential growth in computing capabilities, the use of sophisticated multivariate methods-- already common-- will soon become ubiquitous and ultimately almost compulsory. While the existence of sophisticated algorithms for disentangling signal and background might naively suggest a diminished role for theorists, the use of the MEM, with its inherent connection to the calculation of differential cross sections will benefit from collaboration between theorists and experimentalists. In this white paper, we will briefly describe the MEM and some of its recent uses, note some current issues and potential resolutions, and speculate about exciting future opportunities.
Multi-element probabilistic collocation method in high dimensions
Foo, Jasmine [Division of Applied Mathematics, Brown University, 182 George St., Box F, Providence, RI 02912 (United States); Karniadakis, George Em [Division of Applied Mathematics, Brown University, 182 George St., Box F, Providence, RI 02912 (United States)], E-mail: gk@dam.brown.edu
2010-03-01T23:59:59.000Z
We combine multi-element polynomial chaos with analysis of variance (ANOVA) functional decomposition to enhance the convergence rate of polynomial chaos in high dimensions and in problems with low stochastic regularity. Specifically, we employ the multi-element probabilistic collocation method MEPCM and so we refer to the new method as MEPCM-A. We investigate the dependence of the convergence of MEPCM-A on two decomposition parameters, the polynomial order {mu} and the effective dimension {nu}, with {nu}<
Jiang, Lijian
2009-05-15T23:59:59.000Z
porous media, oil reservoir simulations and subsurface characterization. In the work, we investigate three main multiscale numerical methods, i.e., multiscale finite element method, partition of unity method and mixed multiscale finite element method...
A fast multipole boundary element method for solving the thin plate bending problem
Liu, Yijun
A fast multipole boundary element method for solving the thin plate bending problem S. Huang, Y: Fast multipole method Boundary element method Thin plate bending problem a b s t r a c t A fast multipole boundary element method (BEM) for solving large-scale thin plate bending problems is presented
REMARKS ON THE MAXIMUM ENTROPY METHOD APPLIED TO FINITE TEMPERATURE LATTICE QCD.
UMEDA, T.; MATSUFURU, H.
2005-07-25T23:59:59.000Z
We make remarks on the Maximum Entropy Method (MEM) for studies of the spectral function of hadronic correlators in finite temperature lattice QCD. We discuss the virtues and subtlety of MEM in the cases that one does not have enough number of data points such as at finite temperature. Taking these points into account, we suggest several tests which one should examine to keep the reliability for the results, and also apply them using mock and lattice QCD data.
Kondagunta, Veeraraghava Gopal
1993-01-01T23:59:59.000Z
contains one repeating pattern of fabric design. The elastic analysis of one such structure yields all the 3D moduli of the composite. There have also been a few papers in the area of damage mechanics of textile composites. Li et. al. [21] used 2D finite... are considered. The understanding gained from this two dimen- sional study can be used to extend these techniques for a complete 3D analysis. The high degree of inhomogeneity in textile composites due to the coarse microstructure makes the O ~ eel 0 Cl CD...
Kim, Jongheon
2013-01-01T23:59:59.000Z
An- alytical Methods in Geomechanics, 31(2):239–259. DvorkinAnalytical Methods in Geomechanics, 28:609–632. Oliver J,and Analytical Methods in Geomechanics, 2:99–128. Ventura G,
Development of a three-dimensional finite element model of a horse's foot
Hanft, Joseph Thomas
1995-01-01T23:59:59.000Z
edges which match up with the edges of slice outline numbers 8 and 11, respectively. ASer the edges had been deimed on the &st two outbnes, the elements were generated. This was accomplished by selecting a set of four connected edges on each slice...
A new Cement to Glue non-conforming Grids with Robin interface conditions: the finite element case
Japhet, Caroline; Nataf, Frédéric
2007-01-01T23:59:59.000Z
We design and analyze a new non-conforming domain decomposition method based on Schwarz type approaches that allows for the use of Robin interface conditions on non-conforming grids. The method is proven to be well posed, and the iterative solver to converge. The error analysis is performed in 2D piecewise polynomials of low and high order and extended in 3D for $P_1$ elements. Numerical results in 2D illustrate the new method.
Parallel hp-Finite Element Simulations of 3D Resistivity Logging Instruments
Torres-Verdín, Carlos
Methods in Metallurgy AGH University of Science and Technology Abstract We simulate electromagnetic (EM
Enhanced finite element analysis using the PATRAN-G pre- and post processor program
Murry, Margaret Lois
1988-01-01T23:59:59.000Z
better and it was concluded that color graphics saved time in the verification of the model. Clarke and Muller conducted a study in which they broke down the cost of a typical analytical solution into twenty percent computing costs and eighty percent... plots, orthographic plots, view control, window control, a color table, plot labeling, and solid contour plots. Other PATRAN-G features are element connectivity optimization, interactive editing of the model, neutral file interfacing, and a large help...
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
2004-01-01T23:59:59.000Z
stream_source_info ESL-PA-04-03-01.pdf.txt stream_content_type text/plain stream_size 30589 Content-Encoding UTF-8 stream_name ESL-PA-04-03-01.pdf.txt Content-Type text/plain; charset=UTF-8 an short-tube using a finite... element model International Journal of Refrig Vol 27 No 2, pp. 176-183The short-tube is used by United States heat pump manufactures as an expansion device because of its lowAnalyse de l’e´coulement d’un frigorige`ne et de la de´formation d’un tube...
De Castro, Carlos Armando
2011-01-01T23:59:59.000Z
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.
Development of geometrically-nonlinear finite element analysis for marine risers
Haas, Mark Edward
1987-01-01T23:59:59.000Z
an element that can work with high-aspect ratio structures. ACKNOWLEDGMENTS I wish to thank Dr. Y. K. "Jack" Lou for his patient persistence, for his strong encouragement, and for deep insight into this reses, rch. Dr. Lou stepped in as the committee... members, Dr. Mogens Henriksen, Dr. Harry A. Hogan, Dr. James R. Morgan, Dr. James K. Nelson, and Dr. John M. Niedziewicki, for their time, support, and criticisms (although not always taken in the proper context). Special thanks go to Dr. Hogan...
Finite element analysis of conjugate heat transfer in axisymmetric pipe flows
Fithen, Robert Miller
1987-01-01T23:59:59.000Z
to x=L. In the unheated section of the tube x(0 and x)L, adiabatic condition apply on the tube exterior. A schematic of the heat transfer model is shown in figure l. The energy equation for i'ully developed laminar flow is 2pcrub 1 ? ? = Kf... ? + ? +? Equation (1) expressed in non ? dimensional form where &q Pe ctR' R i)R r R=- Ti 2pcsubri Pe = f (2) u(r) ri nine noded lagrangian element Fig. 1 Heat transfer model for a circular tube for constant heat flux for constant temperature case From...
Damage Identification of a Composite Beam Using Finite Element Model Updating
Moaveni, Babak; He, Xianfei; Conte, Joel P; De Callafon, Raymond A.
2008-01-01T23:59:59.000Z
Shevitz, D. W. (1996), Damage identification in structuresreview of vibration-based damage identification methods, TheM. , & Samman, M. M. (1991), Damage detection from changes
Magdeburg, Universität
element methods [11, 30, 32], finite volume methods [3, 12, 13], stochastic methods [8, 9, 26], moment methods [34] and sectional methods [17, 18, 22, 23]. A large variety of finite element methods, finite volume methods, weighted residuals, the method of orthogonal collocation and Galerkin's method
Hopkins, P.L.; Eaton, R.R.; Bixler, N.E.
1991-12-01T23:59:59.000Z
A family of finite element computer programs has been developed at Sandia National Laboratories (SNL) most recently, NORIA-SP. The original NORIA code solves a total of four transport equations simultaneously: liquid water, water vapor, air, and energy. Consequently, use of NORIA is computer-intensive. Since many of the applications for which NORIA is used are isothermal, we decided to ``strip`` the original four-equation version, leaving only the liquid water equation. This single-phase version is NORIA-SP. The primary intent of this document is to provide the user of NORIA-SP an accurate user`s manual. Consequently, the reader should refer to the NORIA manual if additional detail is required regarding the equation development and finite element methods used. The single-equation version of the NORIA code (NORIA-SP) has been used most frequently for analyzing various hydrological scenarios for the potential underground nuclear waste repository at Yucca Mountain in western Nevada. These analyses are generally performed assuming a composite model to represent the fractured geologic media. In this model the material characteristics of the matrix and the fractures are area weighted to obtain equivalent material properties. Pressure equilibrium between the matrix and fractures is assumed so a single conservation equation can be solved. NORIA-SP is structured to accommodate the composite model. The equations for water velocities in both the rock matrix and the fractures are presented. To use the code for problems involving a single, nonfractured porous material, the user can simply set the area of the fractures to zero.
Higher-Order, Space-Time Adaptive Finite Volume Methods: Algorithms, Analysis and Applications
Minion, Michael
2014-04-29T23:59:59.000Z
The four main goals outlined in the proposal for this project were: 1. Investigate the use of higher-order (in space and time) finite-volume methods for fluid flow problems. 2. Explore the embedding of iterative temporal methods within traditional block-structured AMR algorithms. 3. Develop parallel in time methods for ODEs and PDEs. 4. Work collaboratively with the Center for Computational Sciences and Engineering (CCSE) at Lawrence Berkeley National Lab towards incorporating new algorithms within existing DOE application codes.
Simplified modeling methods for mechanically fastened connections in flight structures
Brewer, Brett Andrew
2012-01-01T23:59:59.000Z
load sharing, failure modes, and basic design are outlined such that later developments in the finite element method
On simple and accurate finite element models for nonlinear bending analysis of beams and plates
Urthaler Lapeira, Yetzirah Yksya
2007-09-17T23:59:59.000Z
¡B ¶ ¡C3x¡C4 (2.11) where the superscript \\U00 denotes the quantities belonging to either the Timoshenko beam theory (fi = 0) or the Reddy-Bickford beam theory (fi 6= 0). The slope U has a difierent meaning for each theory, as deflned below U = 8... unifled beam element, the axial displacement ^u0(^x) and transverse de ection ^w0(^x) are interpolated as ^u0(^x) = 2X j=1 ^ujˆj(^x) ^w0(^x) = 4X j=1 ¢j`j(^x); ^u1 = ^u0( ^x1); ^u2 = ^u0( ^x2) (2.22a) ¢1 = ^w0( ^x1); ¢2 = ( ^x1); ¢3 = ^w0( ^x2); ¢4...
Stability Analysis for a Saline Boundary Layer Formed by Uniform Up ow Using Finite Elements
Eindhoven, Technische Universiteit
density in the deeper underground and high salt water density at the boundary layer), gravitation plays and Darcy's law. In this report we #12;rst give an overview of semi-analytical methods to analyse
Hoffman, E.L.; Ammerman, D.J.
1995-04-01T23:59:59.000Z
A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several 2D and 3D finite element simulations of the event. The purpose of the work is to investigate the performance of various analysis codes and element types on a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry. During the pulse buckling tests, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. Numerical simulations of the test were performed using PRONTO, a Sandia developed transient dynamics analysis code, and ABAQUS/Explicit with both shell and continuum elements. The calculations are compared to the tests with respect to deformed shape and impact load history.
A top quark mass measurement using a matrix element method
Linacre, Jacob Thomas; /Oxford U.
2010-02-01T23:59:59.000Z
A measurement of the mass of the top quark is presented, using top-antitop pair (t{bar t}) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p{bar p} collision data at centre-of-mass energy {radical}s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t{bar t}) and background (W+jets) matrix elements, as well as a set of parameterised jet-to-parton mapping functions. The likelihood function is maximised with respect to the top quark mass, the fraction of signal events, and a correction to the jet energy scale (JES) of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) provides an in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using 578 lepton+jets candidate events corresponding to 3.2 fb{sup -1} of integrated luminosity, the top quark mass is measured to be m{sub t} = 172.4 {+-} 1.4 (stat+{Delta}{sub JES}) {+-} 1.3 (syst) GeV=c{sup 2}, one of the most precise single measurements to date.
FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA
Taylor, Gary
1 FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA Gareth A.Taylor@brunel.ac.uk ABSTRACT This paper presents the computational modelling of welding phenomena within a versatile numerical) and Computational Solid Mechanics (CSM). With regard to the CFD modelling of the weld pool fluid dynamics, heat
Appelö, Daniel
and periodic boundary conditions. The fully discrete version of the method conserves a discrete energy; curvilinear grids ; finite differences; stability; energy estimate; seismic wave propagation 1 Introduction, such as gas pipes, wave guides, railroad rails and disc brakes. In the vast majority of wave propagation
A MT System from Turkmen to Turkish Employing Finite State and Statistical Methods
Yanikoglu, Berrin
between close language pairs can be relatively easier and can still benefit from simple(r) paradigms in MT with a disambiguation post-processing stage based on statistical language models. The very productive inflectionalA MT System from Turkmen to Turkish Employing Finite State and Statistical Methods A. Cüneyd TANTU
Berry, R. Stephen
Power and efficiency limits for internal combustion engines via methods of finite publication 17 June 1993) Analytical expressionsfor the upper bounds of power and efficiency of an internal power and maxi- mum efficiency. A new step taken in this work beyond Refs. 5 and 6 is the estimation
Zhai, Pengwang
2009-06-02T23:59:59.000Z
meter. 60 20 Geometry of a scattering event. . . . . . . . . . . . . . . . . . . . . . 63 21 An example of the atmosphere model used in the 3D Monte Carlo code for the vector radiative transfer systems. Inhomogeneous layers are divided into voxels... cases can be solved analytically. Several popular numerical methods include the T-matrix method [15, 16, 17, 18, 19], finite-element method [20, 21], finite-difference time-domain(FDTD)method[22,23,24,25,26,27,28,29,30,31,32], point-matching method [33...
Finite element modeling of long-term fluid-structure interaction problems in geological media
Anderson, C.A.
1980-01-01T23:59:59.000Z
A model is developed to predict long-term thermal creep and creep rupture in geological structures under multiaxial stress states and under elevated temperature conditions. An example of the method is given showing the behavior of the crust and mantle while undergoing intrusion by a low density diaper. (ACR)
Finite element study of multi-modal vibration damping for thermal barrier coating applications
barriers for gas turbine blades, there is a growing interest in devel- oping multifunctional coatings methods is critical in many tech- nologies and especially so for gas turbine engines since many the spinning up of the turbine to avoid resonances. One of the advances made in gas turbine technologies, has
Madabhushi, S. S. C.; Madabhushi, S. P. G.
2014-10-29T23:59:59.000Z
of the 15th World Conference on Earthquake Engineering, Lisbon, Paper ID 3705. [18] Chan, A.H.C., (1988), A generalised fully coupled effective stress based computer procedure for problems in Geomechanics, SWANDYNE User Manual, Swansea, UK. [19... . 7, 667–691. [27] Pastor, M., Zienkiewicz, O.C. and Leung, K.H., (1985). Simple model for transient soil loading in earthquake analysis. II: Non-associative models for sands, Int. Journal of Numerical and Analytical Methods in Geomechanics, Vol.9...
Cambridge, University of
Finite element simulation of laser spot welding A. De, S. K. Maiti, C. A. Walsh and H. K. D. H laser spot welding, taking into account the temperature dependence of the physical properties and latent formation during laser spot welding, although the `double ellipsoidal' representation requires an a priori
Haigh, Stuart
Madabhushi & Haigh: The pull-out behaviour of piles. 1 FINITE ELEMENT ANALYSIS OF PILE FOUNDATIONS.K.HAIGH, Cambridge University Engineering Department, UK ABSTRACT: The behaviour of piles in sand under tensile-out resistance with soil density, pile size and speed of pull was investigated in an attempt to predict pile
A Massively Parallel Sparse Eigensolver for Structural Dynamics Finite Element Analysis
Day, David M.; Reese, G.M.
1999-05-01T23:59:59.000Z
Eigenanalysis is a critical component of structural dynamics which is essential for determinating the vibrational response of systems. This effort addresses the development of numerical algorithms associated with scalable eigensolver techniques suitable for use on massively parallel, distributed memory computers that are capable of solving large scale structural dynamics problems. An iterative Lanczos method was determined to be the best choice for the application. Scalability of the eigenproblem depends on scalability of the underlying linear solver. A multi-level solver (FETI) was selected as most promising for this component. Issues relating to heterogeneous materials, mechanisms and multipoint constraints have been examined, and the linear solver algorithm has been developed to incorporate features that result in a scalable, robust algorithm for practical structural dynamics applications. The resulting tools have been demonstrated on large problems representative of a weapon's system.
Finite element analysis of the I-40 bridge over the Rio Grande
Farrar, C.R.; Duffey, T.A.; Goldman, P.A.; Jauregui, D.V.; Vigil, J.S.
1996-01-01T23:59:59.000Z
In the 1960s and 1970s numerous bridges were built in the US with a design similar to those on Interstate 40 (I-40) over the Rio Grande in Albuquerque, New Mexico. The Federal Highway Administration (FHWA) and the National Science Foundation (NSF) have provided funds to New Mexico State University (NMSU) through the New Mexico State Highway and Transportation Department (NMSH and TD) and The Alliance For Transportation Research (ATR) for evaluation and testing of the existing fracture-critical bridges over the Rio Grande. Because the I-40 Bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce damage into the structure in order to test various damage identification methods and to observe the changes in load paths through the structure caused by the cracking. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. A previous report (LA-12767-MS) summarizes the results of the experimental modal analyses. This report summarizes the numerical analyses of the bridges and compares the results of these analyses to the experimental results.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Tezaur, I. K.; Perego, M.; Salinger, A. G.; Tuminaro, R. S.; Price, S. F.
2015-04-27T23:59:59.000Z
This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, alongmore »with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.« less
Tezaur, I. K. [Sandia National Laboratories; Perego, M. [Sandia National Laboratories; Salinger, A. G. [Sandia National Laboratories; Tuminaro, R. S. [Sandia National Laboratories; Price, S. F. [Los Alamos National Laboratory
2015-01-01T23:59:59.000Z
This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, along with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.
Quinones, Armando (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2006-06-01T23:59:59.000Z
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.
Pettit, J. R. [Rolls-Royce Nuclear, PO BOX 2000, Derby, UK, DE21 7XX and Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Walker, A. [Rolls-Royce Nuclear, PO BOX 2000, Derby DE21 7XX (United Kingdom); Lowe, M. J. S. [Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2014-02-18T23:59:59.000Z
Defects which posses rough surfaces greatly affect ultrasonic wave scattering behaviour, often reducing the magnitude of reflected signals. Ultrasonic inspections rely upon this response for detecting and sizing flaws. For safety critical components reliable characterisation is crucial. Therefore, providing an accurate means to predict reductions in signal amplitude is essential. An extension of Kirchhoff theory has formed the basis for the UK power industry inspection justifications. However, it is widely recognised that these predictions are pessimistic owing to analytical approximations. A numerical full field modelling approach does not fall victim to such limitations. Here, a Finite Element model is used to aid in setting a non-conservative reporting threshold during the inspection of a large pressure vessel forging that might contain embedded rough defects. The ultrasonic response from multiple rough surfaces defined by the same statistical class is calculated for normal incident compression waves. The approach is validated by comparing coherent scattering with predictions made by Kirchhoff theory. At lower levels of roughness excellent agreement is observed, whilst higher values confirm the pessimism of Kirchhoff theory. Furthermore, the mean amplitude in the specular direction is calculated. This represents the information obtained during an inspection, indicating that reductions due to increasing roughness are significantly less than the coherent component currently being used.
System and method for reproducibly mounting an optical element
Eisenbies, Stephen; Haney, Steven
2005-05-31T23:59:59.000Z
The present invention provides a two-piece apparatus for holding and aligning the MEMS deformable mirror. The two-piece apparatus comprises a holding plate for fixedly holding an adaptive optics element in an overall optical system and a base spatially fixed with respect to the optical system and adapted for mounting and containing the holding plate. The invention further relates to a means for configuring the holding plate through adjustments to each of a number of off-set pads touching each of three orthogonal plane surfaces on the base, wherein through the adjustments the orientation of the holding plate, and the adaptive optics element attached thereto, can be aligned with respect to the optical system with six degrees of freedom when aligning the plane surface of the optical element. The mounting system thus described also enables an operator to repeatedly remove and restore the adaptive element in the optical system without the need to realign the system once that element has been aligned.
Method for recovering catalytic elements from fuel cell membrane electrode assemblies
Shore, Lawrence (Edison, NJ); Matlin, Ramail (Berkeley Heights, NJ); Heinz, Robert (Ludwigshafen, DE)
2012-06-26T23:59:59.000Z
A method for recovering catalytic elements from a fuel cell membrane electrode assembly is provided. The method includes converting the membrane electrode assembly into a particulate material, wetting the particulate material, forming a slurry comprising the wetted particulate material and an acid leachate adapted to dissolve at least one of the catalytic elements into a soluble catalytic element salt, separating the slurry into a depleted particulate material and a supernatant containing the catalytic element salt, and washing the depleted particulate material to remove any catalytic element salt retained within pores in the depleted particulate material.
Analysis of Topological Chaos in Ghost Rod Mixing at Finite Reynolds Numbers Using Spectral Methods
Rao, Pradeep C.
2011-02-22T23:59:59.000Z
December 2009 Major Subject: Mechanical Engineering ANALYSIS OF TOPOLOGICAL CHAOS IN GHOST ROD MIXING AT FINITE REYNOLDS NUMBERS USING SPECTRAL METHODS A Thesis by PRADEEP CHANDRAKANT RAO Submitted to the Office of Graduate Studies of Texas A&M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Andrew T. Duggleby Committee Members, N. K. Anand Hamn-Ching Chen Head of Department, Dennis O?Neil December 2009 Major Subject: Mechanical...
Calisch, Samuel Eli
2014-01-01T23:59:59.000Z
Engineering with digital materials, by discretely and reversibly assembling structure and function from a mass-produced construction kit of parts, is indeed an exciting vision. The ability to decouple conventionally linked ...