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 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
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
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
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
A frequency domain finite element model for tidal circulation
Westerink, Joannes J.
1985-01-01T23:59:59.000Z
A highly efficient finite element model has been developed for the numerical prediction of depth average circulation within small scale embayments which are often characterized by irregular boundaries and bottom topography.
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.
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
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
Finite element modeling of syntactic foam.
Hobbs, Michael L.
2004-10-01T23:59:59.000Z
A decomposition model has been developed to predict the response of removable syntactic foam (RSF) exposed to fire-like heat fluxes. RSF consists of glass micro-balloons (GMB) in a cured epoxy polymer matrix. A chemistry model is presented based on the chemical structure of the epoxy polymer, mass transport of polymer fragments to the bulk gas, and vapor-liquid equilibrium. Thermophysical properties were estimated from measurements. A bubble nucleation, growth, and coalescence model was used to describe changes in properties with the extent of reaction. Decomposition of a strand of syntactic foam exposed to high temperatures was simulated.
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
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
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 ...
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¦
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 Multi-physics Modeling for Ohmic Contact of Microswitches , D. Leray1, 2
Boyer, Edmond
Finite Element Multi-physics Modeling for Ohmic Contact of Microswitches H.Liu1, 2 , D. Leray1, 2-physics modelling of electrical contact is accomplished with the finite element commercial package ANSYSTM . Two behaviour of electrical contact with rough surface included. Keywords: multi-physics, finite element
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.
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.
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
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)
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.
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.
Structural Analysis of a New Design of a Glenoid Prosthesis by Finite Element Modeling
Downey, John A
1990-01-01T23:59:59.000Z
18 Abstract Prosthesis loosening in total shoulderexcision. Present glenoid prostheses have fixation only inDesign of a Glenoid Prosthesis by Finite Element Modeling By
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.
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 ...
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
2003-12-06T23:59:59.000Z
FVE is closely related to the control volume finite element method ... simple stencils, to apply to a fairly wide range of fluid flow equations, to effectively treat.
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 ...
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...
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method
Wang, G.; Liu, M.
2005-01-01T23:59:59.000Z
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method Gang Wang Research Associate University of Nebraska – Lincoln Mingsheng Liu Professor University of Nebraska – Lincoln David E. Claridge Professor Texas A... be decoupled using a constant sensible heat ratio (SHR) and the saturation humidity ratio vs. temperature curve can be treated as linear in a small area corresponding to a finite element of the coil. This paper presents the decoupled cooling coil model...
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors
Pietra, Paola
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors Stefan Holst #12;tting mixed #12;nite-element method is used to discretize the stationary energy. Energy-transport models describe the ow of electrons through a semi- conductor device, in uenced by di
A Finite Element Algorithm of a Nonlinear Diffusive Climate Energy Balance Model
DÃaz, JesÃºs Ildefonso
A Finite Element Algorithm of a Nonlinear Diffusive Climate Energy Balance Model R. BERMEJO,1 J. This model belongs to the category of energy balance models introduced independently by the climatologists M climate. The energy balance model we are dealing with consists of a two-dimensional nonlinear parabolic
Styles, Vanessa
Finite element analysis of a current density - electric #12;eld formulation of Bean's model a current density-electric #12;eld formulation of Bean's model for the experimental set-up of a in#12;nitely. As observed by Bossavit, [4], Bean's critical state model can be formulated as a degenerate Stefan problem
A FINITE ELEMENT APPROXIMATION OF A VARIATIONAL INEQUALITY FORMULATION OF BEAN'S MODEL FOR
Elliott, Charles
A FINITE ELEMENT APPROXIMATION OF A VARIATIONAL INEQUALITY FORMULATION OF BEAN'S MODEL of a variational formulation of Bean's model for the physical configuration of an infinitely long cylindrical's axis, for x R2 . The well-known Bean critical state model can be formulated as an evolutionary
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
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.
Finite-element discretization of a linearized 2 -D model for lubricated oil transportation
Frey, Pascal
Finite-element discretization of a linearized 2 - D model for lubricated oil transportation V acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy
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
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
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.
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
Puckett, A.D.
2000-09-01T23:59:59.000Z
The ability to model wave propagation in circular cylindrical bars of finite length numerically or analytically has many applications. In this thesis the capability of an explicit finite element method to model longitudinal waves in cylindrical rods with circular cross-sections is explored. Dispersion curves for the first four modes are compared to the analytical solution to determine the accuracy of various element sizes and time steps. Values for the time step and element size are determined that retain accuracy while minimizing computational time. The modeling parameters are validated by calculating a signal propagated with a broadband input force. Limitations on the applicability are considered along with modeling parameters that should be applicable to more general geometries.
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01T23:59:59.000Z
T. (1999). Computational Geomechanics with Special ReferenceDynamic Problems in Geomechanics," PhD Thesis, Universityon Numerical Models in Geomechanics, G. N. Pande, Van Impe,
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01T23:59:59.000Z
Failure of Sand Slope in Centrifuge Test." Proceedings ofStephen E. (2001b). "Centrifuge Modeling of Pile-Supportedof Site Liquefaction Using Centrifuge Tests." Proceedings of
One dimensional electroseismic modeling using the finite element ...
2013-01-30T23:59:59.000Z
Section is devoted to a description of the Earth model and electromagnetic source ...... wave phenomena in fluid-saturated sediments”, J. Geophys. Res. .... [
Probabilistic finite element analysis of marine risers
Leder, H. Vern
1990-01-01T23:59:59.000Z
Review 1. 2 Research Study 10 2 FORMULATION OF THE SECOND ? MOMENT ANALYSIS METHOD 13 2. 1 Finite Element Equations 2. 2 Random Vector Formulation 2. 3 The Correlation Function 2. 4 Random Field Discretization 2. 5 Taylor Series Expansion 2. 6... 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...
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
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
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
Modeling of board-level package by Finite Element Analysis and laser interferometer measurements
Cao, Wenwu
and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai be simulated by an equivalent Finite Element Analysis (FEA) model of the board-level package, in which detailed layer structure of the Print Circuit Board (PCB), signal wires and through-holes were ignored
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
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials
Paris-Sud XI, Université de
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials A. Karrech a,, A. Seibi thrust is the introduc- tion of the "Chicago" law in a continuum approach to account for the ratcheting or jointly with the ratcheting effect. Non-associated plasticity is adopted since the paper mainly targets
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
Suciu, Nicolae
A mixed finite element discretization scheme for a concrete carbonation model with concentration/unsaturated porous media. The special features of our problem are twofold: the reaction produces water and therefore for the case of concrete carbonation Â one of the most important physico-chemical processes affecting
Integrating Tactile and Force Feedback with Finite Element Models
, impedances of robot arms, and the computational model. We also describe an implementation of a compliance rendering system combining a low-impedance robot arm for large workspace kinesthetic force feedback, a high on a low-impedance robot arm, used here as a force feedback device. A real-time FEM model accepts user
Development of a finite element model of decompressive craniectomy
Fletcher, Tim L.; Kolias, Angelos G.; Hutchinson, Peter J. A.; Sutcliffe, Michael P. F.
2014-07-15T23:59:59.000Z
would be lost. One aspect that needs to be considered carefully is the type of material model required. In decompressive craniectomy there is a hybrid of confined and unconfined loading, which means that conclusions drawn on appropriate material models... Neurology 9(7): 405–15. 10. Elkin BS, Morrison B (2007) Region-specific tolerance criteria for the living brain. Stapp Car Crash Journal 51: 127–38. 11. Miller K, Wittek A, Joldes G, Horton A, Dutta-Roy T, et al. (2010) Modelling brain deformations...
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
1980-01-01T23:59:59.000Z
into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...
Finite-element harmonic experiments to model fractured induced ...
santos
Mar 10, 2014 ... Krzikalla and Müller [7] combined the two previous models to obtain ... Among other works employing numerical simulations to analyze dispersion, ...... layered fluid and gas saturated sediments, Geophysics 62 (1997) ...
Finite element modeling of SHTE and PSVTM electroseismics
Fabio I. Zyserman
2010-10-07T23:59:59.000Z
algorithm to model diffusive electric fields induced by SH waves;. Garambois and Dietrich (2002) ... Santos and Sheen (2007); and the corresponding dispersion analysis was presented in ...... in fluid-saturated sediments. J. Geophys. Res. 111
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
Phase Reduction Models for Improving the Accuracy of the Finite Element Solution of
Boyer, Edmond
, acoustic scattering, short-wave problem, finite element method, pollution, accuracy, On-Surface Radiation in view of a numerical finite element solution. It is well-known that pollution error causes inaccuracies the pollution error in the finite element solution of time-harmonic scattering problems. The pollution error
Analysis of a finite element formulation for modelling phase separation
Wells, G N; Garikipati, Krishna
2007-01-01T23:59:59.000Z
The Cahn-Hilliard equation is of importance in materials science and a range of other fields. It represents a diffuse interface model for simulating the evolution of phase separation in solids and fluids, and is a nonlinear fourth-order parabolic...
James, Stephen M.
2011-08-08T23:59:59.000Z
The subject of this thesis is an extension of a two-dimensional, axisymmetric, Timoshenko-beam finite-element rotordynamic code to include a three-dimensional non-axisymmetric solid-element casing model. Axisymmetric beams are sufficient to model...
Boyer, Edmond
identification method - associating a direct finite element model of Gleeble tests and an optimization module1 Inverse Finite Element Modelling and Identification of Constitutive Parameters of UHS Steel Based-2 ) hc heat transfer coefficient at interface between specimen and grips (W m-2 K) hth_eff effective
Simulation of dynamic fracture using peridynamics, finite element modeling, and contact.
Littlewood, David John
2010-11-01T23:59:59.000Z
Peridynamics is a nonlocal extension of classical solid mechanics that allows for the modeling of bodies in which discontinuities occur spontaneously. Because the peridynamic expression for the balance of linear momentum does not contain spatial derivatives and is instead based on an integral equation, it is well suited for modeling phenomena involving spatial discontinuities such as crack formation and fracture. In this study, both peridynamics and classical finite element analysis are applied to simulate material response under dynamic blast loading conditions. A combined approach is utilized in which the portion of the simulation modeled with peridynamics interacts with the finite element portion of the model via a contact algorithm. The peridynamic portion of the analysis utilizes an elastic-plastic constitutive model with linear hardening. The peridynamic interface to the constitutive model is based on the calculation of an approximate deformation gradient, requiring the suppression of possible zero-energy modes. The classical finite element portion of the model utilizes a Johnson-Cook constitutive model. Simulation results are validated by direct comparison to expanding tube experiments. The coupled modeling approach successfully captures material response at the surface of the tube and the emerging fracture pattern. The coupling of peridynamics and finite element analysis via a contact algorithm has been shown to be a viable means for simulating material fracture in a high-velocity impact experiment. A combined peridynamics/finite element approach was applied to model an expanding tube experiment performed by Vogler, et al., in which loading on the tube is a result of Lexan slugs impacting inside the tube. The Lexan portion of the simulation was modeled with finite elements and a Johnson-Cook elastic-plastic material model in conjunction with an equation-of-state law. The steel tube portion of the simulation was modeled with peridynamics, an elastic-plastic material model, and a critical stretch bond damage model. The application of peridynamics to the tube portion of the model allowed the capture of the formation of cracks and eventual fragmentation of the tube. The simulation results yielded good agreement with the experimental results published by Vogler, et al., for the velocity and displacement profiles on the surface of the tube and the resulting fragment distribution. Numerical difficulties were encountered that required removal of hexahedron elements from the Lexan portion of the model over the course of the simulation. The significant number of inverted and nearly-inverted elements appearing over the course of the simulation is believed to be a result of irregularities in the contact between the Lexan and AerMet portions of the model, and was likely exacerbated by the ultra-high strength of the AerMet tube. Future simulations are planned in which the Lexan portion of the simulation is modeled with peridynamics, or with an alternative method such as smoothed particle hydrodynamics, with the goal of reducing these numerical difficulties.
Boyer, Edmond
- 1 - Implementation of surface tension with wall adhesion effects in a three-dimensional finite element modelling of surface tension. The external stress vectors associated with surface tension a drop of liquid on a plane is treated. Keywords : surface tension, finite element method, average
Finite Element Model of Training in the superconducting quadrupole magnet SQ02
Caspi, Shlomo; Ferracin, Paolo
2007-11-01T23:59:59.000Z
This paper describes the use of 3D finite element models to study training in superconducting magnets. The simulations are used to examine coil displacements when the electromagnetic forces are cycled, and compute the frictional energy released during conductor motion with the resulting temperature rise. A computed training curve is then presented and discussed. The results from the numerical computations are compared with test results of the Nb{sub 3}Sn racetrack quadrupole magnet SQ02.
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.
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.
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.
Efficient Computation of Info-Gap Robustness for Finite Element Models
Stull, Christopher J. [Los Alamos National Laboratory; Hemez, Francois M. [Los Alamos National Laboratory; Williams, Brian J. [Los Alamos National Laboratory
2012-07-05T23:59:59.000Z
A recent research effort at LANL proposed info-gap decision theory as a framework by which to measure the predictive maturity of numerical models. Info-gap theory explores the trade-offs between accuracy, that is, the extent to which predictions reproduce the physical measurements, and robustness, that is, the extent to which predictions are insensitive to modeling assumptions. Both accuracy and robustness are necessary to demonstrate predictive maturity. However, conducting an info-gap analysis can present a formidable challenge, from the standpoint of the required computational resources. This is because a robustness function requires the resolution of multiple optimization problems. This report offers an alternative, adjoint methodology to assess the info-gap robustness of Ax = b-like numerical models solved for a solution x. Two situations that can arise in structural analysis and design are briefly described and contextualized within the info-gap decision theory framework. The treatments of the info-gap problems, using the adjoint methodology are outlined in detail, and the latter problem is solved for four separate finite element models. As compared to statistical sampling, the proposed methodology offers highly accurate approximations of info-gap robustness functions for the finite element models considered in the report, at a small fraction of the computational cost. It is noted that this report considers only linear systems; a natural follow-on study would extend the methodologies described herein to include nonlinear systems.
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.
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).
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.
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...
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...
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.
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
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
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
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
reliability. Short-tubes have either a constant inner dia- meter flow channel or a tapered channel with a smallAbstract A finite element model was used to simulate single-phase flow of R-22 through flexible short-tubes. The numerical model included the fluid... in the flow area. The more flexible (5513 kPa) short-tube restricted the mass flow rate more than the most rigid (9889 kPa) short-tube used in this study. The mass flow rates estimated with the finite element model were as much as 14% higher than those from...
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.
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
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
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.
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.
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
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...
Regueiro, Richard A.
, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneouslyFinite element analysis of grain-matrix micro-cracking in shale within the context of a multiscale-cracking in shale at grain-matrix inter- faces, assuming constituents are composed of quart silt grains
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... visualization and functional analysis, building 3D surface models through serial reconstruction has received much attention in biomedical research [3], [8], [50]. Surface reconstruction techniques include volume rendering, iso-surface algorithms, parametric...
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.
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 multiscale preconditioner for stochastic mortar mixed finite elements
Yotov, Ivan
physical models in different subdomains. The mortar finite element method is a generalization is the stochastic collocation method [4,40,39]. It combines a finite element discretiza- tion in physical space the approximation properties of the stochastic finite element method [5,37], making it more efficient than MCS
Koteras, J.R.
1993-07-01T23:59:59.000Z
Tunnels buried deep within the earth constitute an important class geomechanics problems. Two numerical techniques used for the analysis of geomechanics problems, the finite element method and the boundary element method, have complementary characteristics for applications to problems of this type. The usefulness of combining these two methods for use as a geomechanics analysis tool has been recognized for some time, and a number of coupling techniques have been proposed. However, not all of them lend themselves to efficient computational implementations for large-scale problems. This report examines a coupling technique that can form the basis for an efficient analysis tool for large scale geomechanics problems through the use of an iterative equation solver.
Adaptive Finite Element Modeling Techniques for the Poisson-Boltzmann Equation
Michael Holst; James Andrew McCammon; Zeyun Yu; Yongcheng Zhou; Yunrong Zhu
2010-09-30T23:59:59.000Z
We develop an efficient and reliable adaptive finite element method (AFEM) for the nonlinear Poisson-Boltzmann equation (PBE). We first examine the regularization technique of Chen, Holst, and Xu; this technique made possible the first a priori pointwise estimates and the first complete solution and approximation theory for the Poisson-Boltzmann equation. It also made possible the first provably convergent discretization of the PBE, and allowed for the development of a provably convergent AFEM for the PBE. However, in practice the regularization turns out to be numerically ill-conditioned. In this article, we examine a second regularization, and establish a number of basic results to ensure that the new approach produces the same mathematical advantages of the original regularization, without the ill-conditioning property. We then design an AFEM scheme based on the new regularized problem, and show that the resulting AFEM scheme is accurate and reliable, by proving a contraction result for the error. This result, which is one of the first results of this type for nonlinear elliptic problems, is based on using continuous and discrete a priori pointwise estimates to establish quasi-orthogonality. To provide a high-quality geometric model as input to the AFEM algorithm, we also describe a class of feature-preserving adaptive mesh generation algorithms designed specifically for constructing meshes of biomolecular structures, based on the intrinsic local structure tensor of the molecular surface. The stability advantages of the new regularization are demonstrated using an FETK-based implementation, through comparisons with the original regularization approach for a model problem. The convergence and accuracy of the overall AFEM algorithm is also illustrated by numerical approximation of electrostatic solvation energy for an insulin protein.
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.
Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA); Foster, C. D. (Stanford University, Stanford, CA)
2006-10-01T23:59:59.000Z
Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report focuses on the development of a constitutive model appropriate to localizing geomaterials, and the embedding of this model into the enhanced finite element framework. This modeling covers two distinct phases. The first, usually brief, phase is the weakening response as the material transitions from intact continuum to a body with a cohesionless fractured surface. Once the cohesion has been eliminated, the response along the surface is completely frictional. We have focused on a rate- and state-dependent frictional model that captures stable and unstable slip along the surface. This model is embedded numerically into the element using a generalized trapezoidal formulation. While the focus is on the constitutive model of interest, the framework is also developed for a general surface response. This report summarizes the major research and development accomplishments for the LDRD project titled 'Cohesive Zone Modeling of Failure in Geomaterials: Formulation and Implementation of a Strong Discontinuity Model Incorporating the Effect of Slip Speed on Frictional Resistance'. This project supported a strategic partnership between Sandia National Laboratories and Stanford University by providing funding for the lead author, Craig Foster, during his doctoral research.
INTRODUCTION TO THE FINITE ELEMENT METHOD
California at Berkeley, University of
in popularity with the finite difference method in the areas of heat transfer and fluid mechanics. 1DRAFT Chapter 1 INTRODUCTION TO THE FINITE ELEMENT METHOD 1.1 Historical perspective: the origins of the finite el- ement method The finite element method constitutes a general tool for the numerical solution
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
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
Antoine, Xavier - Institut de MathÃ©matiques Ã?lie Cartan, UniversitÃ© Henri PoincarÃ©
Accepted 12 January 2009 Available online 21 January 2009 Keywords: Helmholtz equation Acoustic scattering Short-wave problem Finite element method Pollution Accuracy On-Surface Radiation Condition method a b- lems in view of a numerical finite element solution. It is well-known that pollution error causes
Jackson, Jason R.
1996-01-01T23:59:59.000Z
described in the ASTM procedure 412. The specimens were then loaded into an Instron Model 4202 with the series IX Version 4. 02 software. Testing was done on an Instron 200 pound load cell. The two data files from Federal Mogul Corporation contained... stress values. The two columns containing the stress and strain data points were saved to a text file in a comma delimited format for subsequent insertion into the ABAQUS input file. Two options are available in ABAQUS for specifying the elastomer...
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.
Finite element analysis of human joints
Bossart, P.L.; Hollerbach, K.
1996-09-01T23:59:59.000Z
Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.
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
James, Stephen M.
2011-08-08T23:59:59.000Z
-dimensional axisymmetric beam-element code. ANSYS is used as a code to build three-dimensional non-axisymmetric solid-element casing models. The work done in this thesis opens the scope to incorporate complex non-axisymmetric casing models with XLTRC2....
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.
Sudarshan, Raghunathan, 1978-
2005-01-01T23:59:59.000Z
We propose a simple and unified approach for a posteriori error estimation and adaptive mesh refinement in finite element analysis using multiresolution signal processing principles. Given a sequence of nested discretizations ...
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 ...
Finite element approximation of coupled seismic and ...
zyserman
layer, having a thickness of about 10 nm. Finite element approximation of coupled seismic and electromagnetic waves in gas hydrate-bearing sediments – p.
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
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
Mixed finite element discretization of a model for organic pollution in waters
Paris-Sud XI, UniversitÃ© de
of the DO and its flux at the boundary. Currently, no oxygen flux is generated by the environmental medium the Biochemical Oxygen Demand and Dissolved Oxygen to which dispersion terms are added. In this work, we propose. The central element of such problems is the oxygen. The main tracers currently used are the density b
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.
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
A finite element model for transient thermal/structural analysis of large composite space structures
Lutz, James Delmar
1986-01-01T23:59:59.000Z
Versus Time at Solar and Antisolar Points For Cross-Section Number 2 84 28 Temperature Versus Time at Solar and Antisolar Points f' or Cross-Section Number 3 . . . . . . . . . . . . . 85 29 Thermal Noments Versus Time 87 30 Thermal Axial Forces... ar bitrar y domain xi v Superscripts conduction element iteration number flux radiation thermal Subscripts initial reference solar unstrained state INTRODVCTION In the next few decades large space structures will be placed into earth...
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.
Lee, Sang Hoon
2012-02-14T23:59:59.000Z
coupled thermo-poro-mechanical FEM simulation was used to model damage/fracture propagation and microseismic events caused by fluid injection. These studies considered wellbore geometry in small-scale modeling and point-source injection, assuming...
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.
2013-01-01T23:59:59.000Z
Circulatory System Model of Heart Failure Jonathan F. Wenk,contracting regions of the heart. These single ventricledilation and help remodel the heart towards a normal state.
Moaveni, Babak; Conte, Joel P; Hemez, François M
2009-01-01T23:59:59.000Z
modeling error). A full factorial design of experiments iserror) (E). A full factorial design of experiments isnumerical). A full-factorial design of experiments is used
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...
adaptive finite element: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
adaptive finite elements: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
Modeling of reactor components using FIDAP: a finite element computer code
Gangadharan, Anand
1989-01-01T23:59:59.000Z
of the Electric Power Research Institute (EPRI). The test famlity resembles a scaled model of a, high pressure injection of cold water into the cold leg and downcomer of s. pressurized water reactor (PWR). This experiment has current relevance because... DECK FOR EPRI/SAI THERMAL MIXING EXPERIMENT 66 B INPUT DECK FOR THE ADVANCED FUEL COOLING SYSTEM . 78 vn LIST OF TABLES Table Page 1 Constants used in the rc ? e model. 18 2 Experimental test values. 20 vsn LIST OF FIGURES Figure 1 Model...
Ionic Polymer-Metal Composites: Thermodynamical Modeling and Finite Element Solution
Arumugam, Jayavel
2012-10-19T23:59:59.000Z
This thesis deals with developing a thermodynamically consistent model to simulate the electromechanical response of ionic polymer-metal composites based on Euler-Bernoulli beam theory. Constitutive assumptions are made for the Helmholtz free...
k - Version of Finite Element Method for Polymer flows using Giesekus Constitutive Model
Deshpande, Kedar M.
2008-01-31T23:59:59.000Z
and hence high Deborah number flows are invariably associated with higher flow rates and thus higher velocities. In many standard model problems such as couette flow, lid driven cavity, expansion, contraction etc, severe deborah number (De) limitations...
A multi-scale iterative approach for finite element modeling of thermal contact resistance
Thompson, Mary Kathryn, 1980-
2007-01-01T23:59:59.000Z
Surface topography has long been considered a key factor in the performance of many contact applications including thermal contact resistance. However, essentially all analytical and numerical models of thermal contact ...
Mongkolcheep, Kathira
2010-10-12T23:59:59.000Z
The purpose of this work is to present a methodology to predict vibrations of drilllstrings for oil recovery service. The work extends a previous model of the drill collar between two stabilizers in the literature to include drill collar flexibility...
A finite element model of the turbulent flow field in a centrifugal impeller
Hlavaty, Steven Todd
1993-01-01T23:59:59.000Z
, or for applications such as pumps utilizing a liquid as the working medium. Full ellipticity of the flow- governing equations throughout the computational domain is rigorously retained. As a result, the model is conceptually capable of predicting real-flow effects... such as flow separation and recirculation, regardless of whether such complex flow behavior is local or massive. Applicability of the model is illustrated using a typical pump impeller of the purely centrifugal type. In presenting the computed flow field...
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.
Finite element and nite volume discretizations of Drift-Di usion type uid models for semiconductors
Brezzi, Franco
Milano Via Bonardi 9, 20133 Milano, Italy z University of Western Australia Department of Mathematics and Statistics Nedlands, Western Australia 6907, Australia This paper is to appear as a Chapter of Numerical the initial/boundary conditions which complete the model. We also consider in more detail the Energy
FINITE ELEMENT APPROXIMATION OF A PHASE FIELD MODEL FOR VOID ELECTROMIGRATION
Styles, Vanessa
;) 2 [ 1; 1]. The above, in the limit ! 0, models the evolution of voids by surface di#11;usion and interfacial tension cause surface di#11;usion; that is, atoms di#11;use from one part of the void boundary to another. The void e#11;ectively \\drifts" through the conductor, changing its shape as it does so
Styles, Vanessa
FOR SUPERCONDUCTIVITY C.M. ELLIOTT, D. KAY #3; AND V.STYLES y CENTRE FOR MATHEMATICAL ANALYSIS AND ITS APPLICATIONS long cylindrical superconductor subject to a transverse magnetic #12;eld. We prove an error between of an evolutionary variational inequality arising from a critical state model for a type-II superconductor
Application of Mass Lumped Higher Order Finite Elements
Chen, J.; Strauss, H. R.; Jardin, S. C.; Park, W.; Sugiyama, L. E.; Fu., G.; Breslau, J.
2005-11-01T23:59:59.000Z
There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied.
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
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II Zhangxin coefficient times the gradient). Based on this formulation, mixed finite element approximations with low permeability and to the transport equation with small dispersion in groundwater modeling
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
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
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
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
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
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
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
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.
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.
Langerman, M.A.
1990-09-01T23:59:59.000Z
Steady-state modeling considerations for simulating the in situ vitrification (ISV) process are documented based upon the finite element numerical approach. Recommendations regarding boundary condition specifications and mesh discretization are presented. The effects of several parameters on the ISV process response are calculated and the results discussed. The parameters investigated include: (1) electrode depth, (2) ambient temperature, (3) supplied current, (4) electrical conductivity, (5) electrode separation, and (6) soil/waste characterization. 13 refs., 29 figs., 1 tab.
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...
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
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
An Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow
Osnes, Harald
of groundwater flow and transport from mathematical models involves considerable uncertainty due to the presenceAn Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow Harald Osnes Hans by nonlinear effects as oe Y approaches unity in more general domains. 1 #12; 1 Introduction The prediction
Min, Kyoung
2013-07-16T23:59:59.000Z
are studied using a coupled thermo-hydro-mechanical (THM) analysis. The models are used to simulate microscopic and macroscopic fracture behaviors of laboratory-scale uniaxial and triaxial experiments on rock using an elastic/brittle damage model considering...
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
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
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
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
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
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
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
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
Interval Finite Element Methods: New Directions Rafi Muhanna1
Kreinovich, Vladik
Interval Finite Element Methods: New Directions Rafi Muhanna1 , Vladik Kreinovich2 , Pavel SolÂ´in2 advanced numerical methods to tackle these problems, such as finite element methods (FEM). Lately, new advanced version of these methods have appeared, such as hierarchic higher-order finite element methods (hp
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert
Treuille, Adrien
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert Carnegie Mellon University Global be solved numerically. In this chapter we explain some of the basics of the finite element method Illumination course notes, SIGGRAPH '93, Anaheim, Aug. 1993 4Â1 #12; 4Â2 Introduction to Finite Element Methods
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 displace- ment-based ÿnite element model with a microstructural Voronoi cell FEM (VCFEM) for multi
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
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...
Morris, J; Johnson, S
2007-12-03T23:59:59.000Z
The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.
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...
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
An application of stochastic finite element method in structural reliabiity
Agrawal, Sanjay
1993-01-01T23:59:59.000Z
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... of the beam on the buckling load. The statistical methodology can be efficiently used with available FORM/SORM reliability techniques to compute the probability of failure of the beam due to buckling. Random fields are used to quantify the modeling...
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
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
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 ...
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.
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.
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
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
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
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.
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 ...
Direct Forcing Immersed Boundary Methods: Finite Element Versus Finite Volume Approach
Frisani, Angelo 1980-
2012-12-07T23:59:59.000Z
Two immersed boundary methods (IBM) for the simulation of conjugate heat transfer problems with complex geometries are introduced: a finite element (IFEM) and a finite volume (IFVM) immersed boundary methods are discussed. In the IFEM a projection...
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.
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
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
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
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).
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.
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...
Current commutator anomalies in finite-element quantum electrodynamics
Dean F. Miller
1993-12-20T23:59:59.000Z
Four-dimensional quantum electrodynamics has been formulated on a hypercubic Minkowski finite-element lattice. The equations of motion have been derived so as to preserve lattice gauge invariance and have been shown to be unitary. In addition, species doubling is avoided due to the nonlocality of the interactions. The model is used to investigate the lattice current algebra. Regularization of the current is shown to arise in a natural and nonarbitrary way. The commutators of the lattice current are calculated and shown to have the expected qualitative behavior. These lattice results are compared to various continuum calculations. (Five figures available from author.)
3-D Finite Element Electromagnetic and Stress Analyses of the JET LB-SRP Divertor Element (Tungsten Lamella Design)
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 ...
Ghosh, Somnath
in polycrystalline titanium alloys G. Venkatramani, S. Ghosh *, M. Mills Department of Mechanical Engineering, Ohio shedding; 3D microstructure model 1. Introduction Two-phase a/b titanium alloys such as Ti-6242 possess make them suitable for a wide range of applications in the aerospace, orthopedic, dental and sporting
Yeh, G.T.
1987-08-01T23:59:59.000Z
The 3DFEMWATER model is designed to treat heterogeneous and anisotropic media consisting of as many geologic formations as desired, consider both distributed and point sources/sinks that are spatially and temporally dependent, accept the prescribed initial conditions or obtain them by simulating a steady state version of the system under consideration, deal with a transient head distributed over the Dirichlet boundary, handle time-dependent fluxes due to pressure gradient varying along the Neumann boundary, treat time-dependent total fluxes distributed over the Cauchy boundary, automatically determine variable boundary conditions of evaporation, infiltration, or seepage on the soil-air interface, include the off-diagonal hydraulic conductivity components in the modified Richards equation for dealing with cases when the coordinate system does not coincide with the principal directions of the hydraulic conductivity tensor, give three options for estimating the nonlinear matrix, include two options (successive subregion block iterations and successive point interactions) for solving the linearized matrix equations, automatically reset time step size when boundary conditions or source/sinks change abruptly, and check the mass balance computation over the entire region for every time step. The model is verified with analytical solutions or other numerical models for three examples.
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
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
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.
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF
Ozel, Tugrul
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF Ti-6Al-4V ALLOY Turul Manufacturing #12;Transactions of NAMRI/SME 50 Volume 38, 2010 excessive heat generation. Usually above 120 m
PARTIALLY PENALIZED IMMERSED FINITE ELEMENT METHODS ...
2015-01-05T23:59:59.000Z
each interface element, it uses IFE functions constructed with piecewise ...... strate this, we plot errors of a classic bilinear IFE solution and a NPP IFE solution in.
Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities
Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Ko, Kwok; /SLAC
2009-03-04T23:59:59.000Z
Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.
A Novel Membrane Finite Element with Drilling Rotations
Kouhia, Reijo
A Novel Membrane Finite Element with Drilling Rotations Reijo Kouhia 1 Abstract. A new low order interpolation is used for the drill rotation #12;eld. Both triangular and quadrilateral elements are considered of freedom. 1 INTRODUCTION In-plane rotational degrees of freedom, \\drilling de- grees of freedom
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.
TOPAZ3D. 3-D Finite Element Heat Transfer
Shapiro, A.B. [Lawrence Livermore National Lab., CA (United States)
1992-02-24T23:59:59.000Z
TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.
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
An Online Data Access System for a Finite Element Program , David Liu2
Stanford University
for a finite element analysis (FEA) program. The system incorporates a commercial off-the-shelf (COTS) database also be observed in the field of finite element analysis (FEA). Modern finite element programs1 An Online Data Access System for a Finite Element Program Jun Peng1 , David Liu2 , and Kincho H
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
Comparative Study of Finite Element Simulation Software
Gardner, Joel D.; Vijayaraghavan, Athulan; Dornfeld, David A
2005-01-01T23:59:59.000Z
including several aerospace alloys. Specifying new materialsin material models of aerospace alloys, it does not have any
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 ...
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.
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.
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.
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.
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
Tuminaro, Ray S.
element simulation of strongly coupled fluid flow, heat transfer, and mass transfer with non methods, stabilized finite element methods. 1. INTRODUCTION Modern computational fluid dynamics flows with unstructured mesh finite element methods. These flow problems are characterized by both
Hierarchical strategy for rapid finite element analysis
Varghese, Julian
2004-09-30T23:59:59.000Z
A new methodology is introduced where the natural hierarchical character of model descriptions and simulation results are exploited to expedite analysis of problems. The philosophy and the different concepts involved are illustrated by implementing...
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 new finite element lifting surface technique
Kocurek, James David
1973-01-01T23:59:59.000Z
~ ~ ~ ~ ~ ~ ~ ~ ~ 34 VITA 39 vi LIST OF FIGURES Figure Page 1. Planar Panel Idealization 13 2. Vortex-Box Lifting Surface Model 14 3. Vortex-Box Trailing Wake Model 4. Spanwise Distribution Of Circulation, Planar Wing 5. Chordwise Distribution Of Circulation... coordinate ? ~ circulation strength, ft /sec 2 p ~ freestream density, slugs/ft 3 o a portion of S and W velocity potential, ft /sec 2 Subscripts a, b, c points in Cartesian space i, g indicies n ~ direction normal to a surface x, y, z with respect...
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
CONTINUOUSTIME FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY
CONTINUOUSÂTIME FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY Zhangxin ChenÂwater system in groundwater hydrology is given. The system is written in a fractional flow formulation, i for an airÂwater system in groundwater hydrology, ff = a; w [1], [11], [26]: @(OEae ff s ff ) @t +r \\Delta
Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING
Dennis, Brian
arterial supply and effectively blocks the external cooling wave from advancing to the core of the brain1 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
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
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.
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
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
Dohrmann, C.R.; Heinstein, M.W.; Jung, J.; Key, S.W.
1999-01-01T23:59:59.000Z
This report documents a collection of papers on a family of uniform strain tetrahedral finite elements and their connection to different element types. Also included in the report are two papers which address the general problem of connecting dissimilar meshes in two and three dimensions. Much of the work presented here was motivated by the development of the tetrahedral element described in the report "A Suitable Low-Order, Eight-Node Tetrahedral Finite Element For Solids," by S. W. Key {ital et al.}, SAND98-0756, March 1998. Two basic issues addressed by the papers are: (1) the performance of alternative tetrahedral elements with uniform strain and enhanced uniform strain formulations, and (2) the proper connection of tetrahedral and other element types when two meshes are "tied" together to represent a single continuous domain.
Bochev, Pavel Blagoveston
2011-06-01T23:59:59.000Z
We develop a new formulation of the Control Volume Finite Element Method (CVFEM) with a multidimensional Scharfetter-Gummel (SG) upwinding for the drift-diffusion equations. The formulation uses standard nodal elements for the concentrations and expands the flux in terms of the lowest-order Nedelec H(curl; {Omega})-compatible finite element basis. The SG formula is applied to the edges of the elements to express the Nedelec element degree of freedom on this edge in terms of the nodal degrees of freedom associated with the endpoints of the edge. The resulting upwind flux incorporates the upwind effects from all edges and is defined at the interior of the element. This allows for accurate evaluation of integrals on the boundaries of the control volumes for arbitrary quadrilateral elements. The new formulation admits efficient implementation through a standard loop over the elements in the mesh followed by loops over the element nodes (associated with control volume fractions in the element) and element edges (associated with flux degrees of freedom). The quantities required for the SG formula can be precomputed and stored for each edge in the mesh for additional efficiency gains. For clarity the details are presented for two-dimensional quadrilateral grids. Extension to other element shapes and three dimensions is straightforward.
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
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
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.
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.
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...
Edwards, W.R.; Hoyer, E.H.; Thompson, A.C.
1985-10-01T23:59:59.000Z
The first crystal of the Brown-Hower x-ray monochromator of the LBL-EXXON 54 pole wiggler beamline at Stanford Synchrotron Radiation Laboratory (SSRL) is subjected to intense synchrotron radiation. To provide an accurate thermal/structural analysis of the existing monochromator design, a finite element analysis (FEA) was performed. A very high and extremely localized heat flux is incident on the Si (220) crystal. The crystal, which possesses pronouncedly temperature-dependent orthotropic properties, in combination with the localized heat load, make the analysis ideally suited for finite element techniques. Characterization of the incident synchrotron radiation is discussed, followed by a review of the techniques employed in modeling the monochromator and its thermal/structural boundary conditions. The results of the finite element analysis, three-dimensional temperature distributions, surface displacements and slopes, and stresses, in the area of interest, are presented. Lastly, the effects these results have on monochromator output flux and resolution are examined.
Finite size scaling for quantum criticality using the finite-element method
Edwin Antillon; Birgit Wehefritz-Kaufmann; Sabre Kais
2012-03-08T23:59:59.000Z
Finite size scaling for the Schr\\"{o}dinger equation is a systematic approach to calculate the quantum critical parameters for a given Hamiltonian. This approach has been shown to give very accurate results for critical parameters by using a systematic expansion with global basis-type functions. Recently, the finite element method was shown to be a powerful numerical method for ab initio electronic structure calculations with a variable real-space resolution. In this work, we demonstrate how to obtain quantum critical parameters by combining the finite element method (FEM) with finite size scaling (FSS) using different ab initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, internuclear distances, electron density, disorder, lattice structure, and external fields for stability of atomic, molecular systems and quantum phase transitions of extended systems. To illustrate the effectiveness of this approach we provide detailed calculations of applying FEM to approximate solutions for the two-electron atom with varying nuclear charge; these include Hartree-Fock, density functional theory under the local density approximation, and an "exact"' formulation using FEM. We then use the FSS approach to determine its critical nuclear charge for stability; here, the size of the system is related to the number of elements used in the calculations. Results prove to be in good agreement with previous Slater-basis set calculations and demonstrate that it is possible to combine finite size scaling with the finite-element method by using ab initio calculations to obtain quantum critical parameters. The combined approach provides a promising first-principles approach to describe quantum phase transitions for materials and extended systems.
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.
HYDRA, A finite element computational fluid dynamics code: User manual
Christon, M.A.
1995-06-01T23:59:59.000Z
HYDRA is a finite element code which has been developed specifically to attack the class of transient, incompressible, viscous, computational fluid dynamics problems which are predominant in the world which surrounds us. The goal for HYDRA has been to achieve high performance across a spectrum of supercomputer architectures without sacrificing any of the aspects of the finite element method which make it so flexible and permit application to a broad class of problems. As supercomputer algorithms evolve, the continuing development of HYDRA will strive to achieve optimal mappings of the most advanced flow solution algorithms onto supercomputer architectures. HYDRA has drawn upon the many years of finite element expertise constituted by DYNA3D and NIKE3D Certain key architectural ideas from both DYNA3D and NIKE3D have been adopted and further improved to fit the advanced dynamic memory management and data structures implemented in HYDRA. The philosophy for HYDRA is to focus on mapping flow algorithms to computer architectures to try and achieve a high level of performance, rather than just performing a port.
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
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.
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 ...
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 ...
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 ...
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...
Kaul, Sandeep P.
2004-09-30T23:59:59.000Z
Spontaneous imbibition plays a very important role in the displacement mechanism of non-wetting fluid in naturally fractured reservoirs. We developed a new 2D two-phase finite element numerical model, as available commercial simulators cannot...
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
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
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
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
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
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
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
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
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
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
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 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
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
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
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 PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES
Biros, George
A PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES RAHUL S. SAMPATH for the discretized finite element operators and the intergrid transfer operations. The key component of our scheme it has a low setup cost. Key words. Geometric Multigrid, Finite Element Method, Linear Octrees, Adaptive
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...
Zhang, Yijun; Cheng, Yang-Tse; Grummon, David S. [Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824 (United States); Materials and Processes Laboratory, General Motors Research and Development Center, Warren, Michigan 48090 (United States); Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824 (United States)
2007-03-01T23:59:59.000Z
Indentation-induced shape memory and superelastic effects are recently discovered thermo-mechanical behaviors that may find important applications in many areas of science and engineering. Theoretical understanding of these phenomena is challenging because both martensitic phase transformation and slip plasticity exist under complex contact loading conditions. In this paper, we develop a three-dimensional constitutive model of shape memory alloys with plasticity. Spherical indentation-induced superelasticity in a NiTi shape memory alloy was simulated and compared to experimental results on load-displacement curves and recovery ratios. We show that shallow indents have complete recovery upon unloading, where the size of the phase transformation region is about two times the contact radius. Deep indents have only partial recovery when plastic deformation becomes more prevalent in the indent-affected zone.
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.
Visualizing Higher Order Finite Elements: FY05 Yearly Report.
Thompson, David; Pebay, Philippe Pierre
2005-11-01T23:59:59.000Z
This report contains an algorithm for decomposing higher-order finite elementsinto regions appropriate for isosurfacing and proves the conditions under which thealgorithm will terminate. Finite elements are used to create piecewise polynomialapproximants to the solution of partial differential equations for which no analyticalsolution exists. These polynomials represent fields such as pressure, stress, and mo-mentim. In the past, these polynomials have been linear in each parametric coordinate.Each polynomial coefficient must be uniquely determined by a simulation, and thesecoefficients are called degrees of freedom. When there are not enough degrees of free-dom, simulations will typically fail to produce a valid approximation to the solution.Recent work has shown that increasing the number of degrees of freedom by increas-ing the order of the polynomial approximation (instead of increasing the number offinite elements, each of which has its own set of coefficients) can allow some typesof simulations to produce a valid approximation with many fewer degrees of freedomthan increasing the number of finite elements alone. However, once the simulation hasdetermined the values of all the coefficients in a higher-order approximant, tools donot exist for visual inspection of the solution.This report focuses on a technique for the visual inspection of higher-order finiteelement simulation results based on decomposing each finite element into simplicialregions where existing visualization algorithms such as isosurfacing will work. Therequirements of the isosurfacing algorithm are enumerated and related to the placeswhere the partial derivatives of the polynomial become zero. The original isosurfacingalgorithm is then applied to each of these regions in turn.3 AcknowledgementThe authors would like to thank David Day and Louis Romero for their insight into poly-nomial system solvers and the LDRD Senior Council for the opportunity to pursue thisresearch. The authors were supported by the United States Department of Energy, Officeof Defense Programs by the Labratory Directed Research and Development Senior Coun-cil, project 90499. Sandia is a multiprogram laboratory operated by Sandia Corporation,a Lockheed-Martin Company, for the United States Department of Energy under contractDE-AC04-94-AL85000.4
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...
Fracture and Fragmentation of Simplicial Finite Elements Meshes using Graphs
Mota, A; Knap, J; Ortiz, M
2006-10-18T23:59:59.000Z
An approach for the topological representation of simplicial finite element meshes as graphs is presented. It is shown that by using a graph, the topological changes induced by fracture reduce to a few, local kernel operations. The performance of the graph representation is demonstrated and analyzed, using as reference the 3D fracture algorithm by Pandolfi and Ortiz [22]. It is shown that the graph representation initializes in O(N{sub E}{sup 1.1}) time and fractures in O(N{sub I}{sup 1.0}) time, while the reference implementation requires O(N{sub E}{sup 2.1}) time to initialize and O(N{sub I}{sup 1.9}) time to fracture, where NE is the number of elements in the mesh and N{sub I} is the number of interfaces to fracture.
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
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.
R.H. Saunders GS concrete growth mitigation project instrumentation and finite element analysis
Adeghe, L.; Hindy, A.; Ho, M.S. [Hydroelectric Business Unit, Ontario Hydro, Toronto, Ontario (Canada)
1995-12-31T23:59:59.000Z
In 1991, concrete expansion due to Alkali-Silica Reaction (ASR), was diagnosed as the cause of operational and structural problems at R.H. Saunders Generating Station. Reestablishment of contraction joints between the generating units by cutting slots was initiated in January 1993 to relieve accumulated stresses and allow further expansion without deforming the turbine-generators. An integral part of the remedial measure is the installation of an extensive instrumentation system and development of detailed finite element models of the powerhouse structures. In total, two hundred and thirty five instruments have been installed. The instruments include surface extensometers, borehole extensometers, crackmeters, stressmeters, pendulums, thermocouples, borehole convergence meters and strain gauges. All the instruments are monitored continuously by an Automatic Data Acquisition System (ADAS) which allows instrument data to be evaluated remotely. This instrumentation system is being used to collect data on the structural concrete expansion and response to slot cutting. To complement the instrumentation data, three different finite element models have been developed for use. The models range from a very detailed representation of a single powerhouse unit to a less detailed model of the sixteen-unit powerhouse. The finite element models have been calibrated to reflect measured data and subsequently used to estimate the location and frequency of future cuts.
Finite-Element Analysis of Biting Behavior and Bone Stress in the
Dumont, Elizabeth R.
Finite-Element Analysis of Biting Behavior and Bone Stress in the Facial Skeletons of Bats biting behavior and bite force data gathered in the field with finite-element (FE) analysis. Our FE words: biting behavior; bone stress; adaptation; finite-ele- ment analysis; Chiroptera Mammal evolution
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
Manzini, Gianmarco [Los Alamos National Laboratory
2012-07-13T23:59:59.000Z
We develop and analyze a new family of virtual element methods on unstructured polygonal meshes for the diffusion problem in primal form, that use arbitrarily regular discrete spaces V{sub h} {contained_in} C{sup {alpha}} {element_of} N. The degrees of freedom are (a) solution and derivative values of various degree at suitable nodes and (b) solution moments inside polygons. The convergence of the method is proven theoretically and an optimal error estimate is derived. The connection with the Mimetic Finite Difference method is also discussed. Numerical experiments confirm the convergence rate that is expected from the theory.
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%.
King, Joshua David
2005-02-17T23:59:59.000Z
that are varied in studying these subsurface structures are the disk radius, disk depth, the transmitter frequency, the transmitter location, and the structure orientation.The results showed that a disk of finite radius behaves similar to an infinite disk at short...
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.
FINITE ELEMENT METHOD FOR SUBSURFACE HYDROLOGY USING A MIXED EXPLICIT-IMPLICIT SCHEME
Narasimhan, T.N.
2011-01-01T23:59:59.000Z
METHOD FOR SUBSURFACE HYDROLOGY USING A MIXED EXPLICIT-arising in subsurface hydrology. These problems includeFinite Element Method in Hydrology," Int. Jour. Num. Meth.
Reis, A. C.; Moreira Filho, L. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); Menezes, M. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); UNESP - Sao Paulo State University, Ilha Solteira Engineering Faculty, DEM, Av. Brasil, 56 - Centro - Ilha Solteira - SP, CEP 15385-000 (Brazil)
2007-04-07T23:59:59.000Z
The aim of this paper consists in presenting a method of simulating the warpage in 7xxx series aluminium alloy plates. To perform this simulation finite element software MSC.Patran and MSC.Marc were used. Another result of this analysis will be the influence on material residual stresses induced on the raw material during the rolling process upon the warpage of primary aeronautic parts, fabricated through machining (milling) at Embraer. The method used to determinate the aluminium plate residual stress was Layer Removal Test. The numerical algorithm Modified Flavenot Method was used to convert layer removal and beam deflection in stress level. With such information about the level and profile of residual stresses become possible, during the step that anticipate the manufacturing to incorporate these values in the finite-element approach for modelling warpage parts. Based on that warpage parameter surely the products are manufactured with low relative vulnerability propitiating competitiveness and price.
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.
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.
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...
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
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 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
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
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
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
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
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
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
Adaptive finite element methods for PDE-constrained optimal control problems
Adaptive finite element methods for PDE-constrained optimal control problems R. Becker1 , M. Braack is discretized by a finite element Galerkin method. The accuracy of the discretization is controlled by residual of heat transfer, fluid flow and parameter estimation. The contents of this article is as follows
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].
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 ...
Shindo, Yasuhide; Narita, Fumio; Mikami, Masaru [Department of Materials Processing, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-02, Sendai 980-8579 (Japan)
2005-06-01T23:59:59.000Z
This paper presents the results of an experimental and numerical investigation in electric fracture behavior of composite [Pb(Zr,Ti)O{sub 3}] double torsion (DT) specimens. DT tests were conducted on a commercial piezoelectric ceramic bonded between two metals. Fracture loads under different electric fields were obtained from the experiment. Nonlinear three-dimensional finite element analysis was also employed to calculate the energy release rate for DT specimens based on the exact (permeable) and approximate (impermeable) crack models. The effects of applied electric field and domain switching on the energy release rate are discussed, and the model predictions are compared with the results of the experiments.
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.
Finite difference model of eccentric labyrinth seals
Davis, Fredrick Michael
1993-01-01T23:59:59.000Z
shaft of a turbomachine, such as a gas turbine engine. To achieve the desired pressure drop between sections, the seal is constructed to convert the pressure energy between sections to kinetic energy in the seal where it is dissipated. When the rotor.... . . . . Finite Difference Method. Generating Eccentric Grids. . . . . . . . . . . . . . . . . . . . . . . . . . Generalizing Finite Difference Relations. . . . Accounting for Rotor Whirl. . . . . . Turbulence Model. . Enthalpy Model. . Boundary Conditions...
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
Finite element meshing approached as a global minimization process
WITKOWSKI,WALTER R.; JUNG,JOSEPH; DOHRMANN,CLARK R.; LEUNG,VITUS J.
2000-03-01T23:59:59.000Z
The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested before this project ended. The primary complexity in the extension was in the connectivity problem formulation. Defining all of the interparticle interactions that occur in three-dimensions and expressing them in mathematical relationships is very difficult.
Stalnaker, Jack Lee
2005-11-01T23:59:59.000Z
;nite elementmethod is attractive, because it allows the model to be discretized into an unstructured mesh, permitting the speci?cation of realistic irregular conductor geometries, and permitting the mesh to be re?ned locally, where ﬁ...
Finite element analyses for seismic shear wall international standard problem
Park, Y.J.; Hofmayer, C.H.
1998-04-01T23:59:59.000Z
Two identical reinforced concrete (RC) shear walls, which consist of web, flanges and massive top and bottom slabs, were tested up to ultimate failure under earthquake motions at the Nuclear Power Engineering Corporation`s (NUPEC) Tadotsu Engineering Laboratory, Japan. NUPEC provided the dynamic test results to the OECD (Organization for Economic Cooperation and Development), Nuclear Energy Agency (NEA) for use as an International Standard Problem (ISP). The shear walls were intended to be part of a typical reactor building. One of the major objectives of the Seismic Shear Wall ISP (SSWISP) was to evaluate various seismic analysis methods for concrete structures used for design and seismic margin assessment. It also offered a unique opportunity to assess the state-of-the-art in nonlinear dynamic analysis of reinforced concrete shear wall structures under severe earthquake loadings. As a participant of the SSWISP workshops, Brookhaven National Laboratory (BNL) performed finite element analyses under the sponsorship of the U.S. Nuclear Regulatory Commission (USNRC). Three types of analysis were performed, i.e., monotonic static (push-over), cyclic static and dynamic analyses. Additional monotonic static analyses were performed by two consultants, F. Vecchio of the University of Toronto (UT) and F. Filippou of the University of California at Berkeley (UCB). The analysis results by BNL and the consultants were presented during the second workshop in Yokohama, Japan in 1996. A total of 55 analyses were presented during the workshop by 30 participants from 11 different countries. The major findings on the presented analysis methods, as well as engineering insights regarding the applicability and reliability of the FEM codes are described in detail in this report. 16 refs., 60 figs., 16 tabs.
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.
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.
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.
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
Boyer, Edmond
microstructures for hip prosthesis Kyungmok KimÂ¹, Bernard ForestÂ¹, Jean GeringerÂ¹* Â¹Ecole Nationale SupÃ©rieure des and fatigue behaviours of pure alumina microstructures found at hip prosthesis. Finite element models are similar to those found at a slip zone between a femoral head and an acetabular cup of hip prosthesis
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
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
DIRECT AND INVERSE APPROXIMATION THEOREMS FOR THE p-VERSION OF THE FINITE ELEMENT METHOD IN THE
Guo, Benqi
of the finite element method, for example, MSC/PROBE, FIESTA, MECHANICA, PHLEX, STRESSCHECK, and STRIPE. In 1980
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
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
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
Ward, Karen
Interval Finite Element Methods: New Directions Rafi Muhanna 1 , Vladik Kreinovich 2 , Pavel Å¸ Sol advanced numerical methods to tackle these problems, such as finite element methods (FEM). Lately, new advanced version of these methods have appeared, such as hierarchic higherÂorder finite element methods (hp
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...
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 ...
FETI-R (Part II): A regularized variational approach for Finite Element Tearing and
FETI-R (Part II): A regularized variational approach for Finite Element Tearing and Interconnecting Laboratories y Albuquerque, New Mexico 87185 Abstract The coarse grid problem of the original FETI method
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...
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
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 ...
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...
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
A finite element viscous flow analysis in a radial turbine scroll
Hill, Donald Lee
1987-01-01T23:59:59.000Z
A FINITE ELEMENT VISCOUS FLOW ANALYSIS IN A RADIAL TURBINE SCROLL A Thesis DONALD LEE HILL JR. Submitted to the Graduate College. of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December... 1987 Major Subject: Mechanical Engineering A FINITE ELEMENT VISCOUS FLOW ANALYSIS IN A RADIAL TURBINE SCROLL A Thesis by DONALD LEE HILL JR. Approved as to style snd content by: Dr. Erian A. Baskharone (Chairman of Conunittee) Dr. Alan B azzolo...
Kondagunta, Veeraraghava Gopal
1993-01-01T23:59:59.000Z
TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA Submitted to the Office of Graduate Studies of Texas ARM University In partial fulffllment... of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject: Aerospace Engineering TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA...
Evaluation of new techniques for two dimensional finite element analysis of woven composites
Gundapaneni, Sitaram Chowdary
1992-01-01T23:59:59.000Z
EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE DECEMBER 1992 Major Subject: Aerospace Engineering EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Approved...
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.
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
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
Hong, Jung-Wuk, 1970-
2004-01-01T23:59:59.000Z
In this thesis we develop some advances in the method of finite spheres which is a truly meshless numerical technique for the solution of boundary value problems on geometrically complex domains. We present the development ...
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.
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
Finite Model Finding for Parameterized Verification
Lisitsa, Alexei
2010-01-01T23:59:59.000Z
In this paper we investigate to which extent a very simple and natural "reachability as deducibility" approach, originated in the research in formal methods in security, is applicable to the automated verification of large classes of infinite state and parameterized systems. The approach is based on modeling the reachability between (parameterized) states as deducibility between suitable encodings of states by formulas of first-order predicate logic. The verification of a safety property is reduced to a pure logical problem of finding a countermodel for a first-order formula. The later task is delegated then to the generic automated finite model building procedures. In this paper we first establish the relative completeness of the finite countermodel finding method (FCM) for a class of parameterized linear arrays of finite automata. The method is shown to be at least as powerful as known methods based on monotonic abstraction and symbolic backward reachability. Further, we extend the relative completeness of ...
Kim, Kyungmok; Géringer, Jean; 10.1177/0954411911422843
2012-01-01T23:59:59.000Z
This paper describes a two-dimensional (2D) finite element simulation for fracture and fatigue behaviours of pure alumina microstructures such as those found at hip prostheses. Finite element models are developed using actual Al2O3 microstructures and a bilinear cohesive zone law. Simulation conditions are similar to those found at a slip zone in a dry contact between a femoral head and an acetabular cup of hip prosthesis. Contact stresses are imposed to generate cracks in the models. Magnitudes of imposed stresses are higher than those found at the microscopic scale. Effects of microstructures and contact stresses are investigated in terms of crack formation. In addition, fatigue behaviour of the microstructure is determined by performing simulations under cyclic loading conditions. It is shown that crack density observed in a microstructure increases with increasing magnitude of applied contact stress. Moreover, crack density increases linearly with respect to the number of fatigue cycles within a given con...
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
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
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
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...
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...
Visualization of high resolution, three-dimensional, nonlinear finite element analyses
Christon, M.A.; Spelce, T.E.
1992-03-24T23:59:59.000Z
A two-pass surface extraction algorithm for adaptive finite element meshes is presented in the context of a visualization study for a particle impact and a turbine containment problem. The direct use of finite element data structures for the computation of external surfaces, surface normals, and derived physical quantities is discussed. An overview of the in-betweening algorithm which compensates for rigid body dynamics is presented with a brief discussion of a {open_quotes}direct-to-videodisk{close_quotes} animation strategy.
Inversion of Robin coefficient by a spectral stochastic finite element approach
Jin Bangti [Department of Mathematics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)], E-mail: kimbtsing@yahoo.com.cn; Zou Jun [Department of Mathematics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)], E-mail: zou@math.cuhk.edu.hk
2008-03-01T23:59:59.000Z
This paper investigates a variational approach to the nonlinear stochastic inverse problem of probabilistically calibrating the Robin coefficient from boundary measurements for the steady-state heat conduction. The problem is formulated into an optimization problem, and mathematical properties relevant to its numerical computations are investigated. The spectral stochastic finite element method using polynomial chaos is utilized for the discretization of the optimization problem, and its convergence is analyzed. The nonlinear conjugate gradient method is derived for the optimization system. Numerical results for several two-dimensional problems are presented to illustrate the accuracy and efficiency of the stochastic finite element method.
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.
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
FINITE ELEMENT SIMULATION OF MACROSCOPIC MACHINING PROCESSES -IMPLEMENTATION OF TIME
Schmidt, Alfred
force and heat flux prediction is triggered that calculates the mechanical and thermal load. It is modeled mathematically by linking heat con- duction equation with the deformation equation on a time with a process model for prediction of cutting forces and heat flux, thermal and mechanical effects during
Nakamachi, Eiji; Yoshida, Takashi; Yamaguchi, Toshihiko; Morita, Yusuke [Dept. of Biomedical Engineering, Doshisha Univ., Kyotanabe, Kyoto, 610-0394 (Japan); Kuramae, Hiroyuki [Dept. of Technol. Management, Osaka Institute of Technol., Asahiku, Osaka, 535-8585 (Japan); Morimoto, Hideo [Furukawa Electric Co. Ltd., Okano, Nishiku, Yokohama, Kanagawa, 220-0073 (Japan)
2014-10-06T23:59:59.000Z
We developed two-scale FE analysis procedure based on the crystallographic homogenization method by considering the hierarchical structure of poly-crystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure can be modeled as a three dimensional representative volume element (RVE). RVE is featured as by 3×3×3 eight-nodes solid finite elements, which has 216 crystal orientations. This FE analysis code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro- scales, and further the crystal texture and hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the wire drawing processes by our two-scale FE analysis code under conditions of various drawing angles of dice. We evaluates the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution.
stabilized finite element methods for coupled geomechanics and ...
Abstract v. Acknowledgments vii. 1 Introduction. 1. 1.1 Problem Statement . ..... recent studies have shifted focus onto coupled modeling (e.g., Settari & Price 1984, ... Water, oil and natural gas are all fluids that exist within the pore spaces and ...
Finite Element Analysis of Three-Phase Piezoelectric Nanocomposites
Maxwell, Kevin S.
2010-10-12T23:59:59.000Z
on performance. The nanocomposite consisted of a polyimide matrix, beta-CN APB/ODPA, enhanced with single wall carbon nanotubes and PZT-5A particles. The polyimide and nan- otube phases were modeled as a single homogenized phase. This results in a two...
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
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
Local Flaps: A Real-Time Finite Element Based Solution to the Plastic Surgery
Liblit, Ben
Local Flaps: A Real-Time Finite Element Based Solution to the Plastic Surgery Defect Puzzle fundamental challenges in plastic surgery is the alter- ation of the geometry and topology of the skin for the patient after the procedure is completed. The plastic surgeon must look at the defect created
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
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
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
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.
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
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
Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.
1984-06-01T23:59:59.000Z
The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.
California at Berkeley, University of
-Galerkin method and subsequently discretize the resulting equations by N + 1 equally-sized finite elementsDRAFT Chapter 9 HYPERBOLIC DIFFERENTIAL EQUATIONS The classical Bubnov-Galerkin finite element equations. In many problems of mechan- ics and convective heat transfer where convection dominates diffusion
Finite element analyses of tool stresses in metal cutting processes
Kistler, B.L. [Sandia National Labs., Livermore, CA (United States)
1997-01-01T23:59:59.000Z
In this report, we analytically predict and examine stresses in tool tips used in high speed orthogonal machining operations. Specifically, one analysis was compared to an existing experimental measurement of stresses in a sapphire tool tip cutting 1020 steel at slow speeds. In addition, two analyses were done of a carbide tool tip in a machining process at higher cutting speeds, in order to compare to experimental results produced as part of this study. The metal being cut was simulated using a Sandia developed damage plasticity material model, which allowed the cutting to occur analytically without prespecifying the line of cutting/failure. The latter analyses incorporated temperature effects on the tool tip. Calculated tool forces and peak stresses matched experimental data to within 20%. Stress contours generally agreed between analysis and experiment. This work could be extended to investigate/predict failures in the tool tip, which would be of great interest to machining shops in understanding how to optimize cost/retooling time.
FINITE ELEMENT ANALYSIS OF JNES/NUPEC SEISMIC SHEAR WALL CYCLIC AND SHAKING TABLE TEST DATA.
XU,J.; NIE, J.; HOFMAYER, C.; ALI, S.
2007-04-12T23:59:59.000Z
This paper describes a finite element analysis to predict the JNES/NUPEC cyclic and shaking table RC shear wall test data, as part of a collaborative agreement between the U.S. NRC and JNES to study seismic issues important to the safe operation of commercial nuclear power plant (NPP) structures, systems and components (SSC). The analyses described in this paper were performed using ANACAP reinforced concrete models. The paper describes the ANACAP analysis models and discusses the analysis comparisons with the test data. The ANACAP capability for modeling nonlinear cyclic characteristics of reinforced concrete shear wall structures was confirmed by the close comparisons between the ANACAP analysis results and the JNES/NUPEC cyclic test data. Reasonable agreement between the analysis results and the test data was demonstrated for the hysteresis loops and the shear force orbits, in terms of both the overall shape and the cycle-to-cycle comparisons. The ANACAP simulation analysis of the JNES/NUPEC shaking table test was also performed, which demonstrated that the ANACAP dynamic analysis with concrete material model is able to capture the progressive degrading behavior of the shear wall as indicated from the test data. The ANACAP analysis also predicted the incipient failure of the shear wall, reasonably close to the actual failure declared for the test specimen. In summary, the analyses of the JNES/NUPEC cyclic and shaking table RC shear wall tests presented in this paper have demonstrated the state-of-the-art analysis capability for determining the seismic capacity of RC shear wall structures.
Bajwa, Christopher S.; Piotter, Jason; Cuta, Judith M.; Adkins, Harold E.; Klymyshyn, Nicholas A.; Fort, James A.; Suffield, Sarah R.
2010-08-11T23:59:59.000Z
Storage casks and transportation packages for spent nuclear fuel (SNF) are designed to confine SNF in sealed canisters or casks, provide structural integrity during accidents, and remove decay through a storage or transportation overpack. The transfer, storage, and transportation of SNF in dry storage casks and transport packages is regulated under 10 CFR Part 72 and 10 CFR Part 71, respectively. Finite Element Analysis (FEA) is used with increasing frequency in Safety Analysis Reports and other regulatory technical evaluations related to SNF casks and packages and their associated systems. Advances in computing power have made increasingly sophisticated FEA models more feasible, and as a result, the need for careful review of such models has also increased. This paper identifies best practice recommendations that stem from recent NRC review experience. The scope covers issues common to all commercially available FEA software, and the recommendations are applicable to any FEA software package. Three specific topics are addressed: general FEA practices, issues specific to thermal analyses, and issues specific to structural analyses. General FEA practices covers appropriate documentation of the model and results, which is important for an efficient review process. The thermal analysis best practices are related to cask analysis for steady state conditions and transient scenarios. The structural analysis best practices are related to the analysis of casks and associated payload during standard handling and drop scenarios. The best practices described in this paper are intended to identify FEA modeling issues and provide insights that can help minimize associated uncertainties and errors, in order to facilitate the NRC licensing review process.
Modeling and Driving Piezoelectric Resonant Blade Elements
for extracting the parameters of the PRB equivalent circuit model: two are direct methods and one is basedrf rjf Figure 3. Equivalent circuit model of the PRB element. Cin is the dielectric capacitance element will bend the van attached to it and the whole structure will vibrate. Optimum operation
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...
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.
Orth, N.J.; Sansguiri, A.M. [Lamar Univ., Beaumont, TX (United States). Dept. of Mechanical Engineering; Orth, F.J. [Edison Welding Inst., Columbus, OH (United States). Structural Integrity Section
1995-08-01T23:59:59.000Z
It has been proven that the p-version of the finite element method results in a higher accuracy for a given mesh compared to the h-version of the finite element method. This investigation demonstrates the accuracy of the displacement and stress field methods in the vicinity of the crack tip using the p-version of the finite element method to compute the linear elastic stress intensity factor. The stress intensity factor for mode II is computed for an edge crack panel using stress and displacement methods and is compared to the analytical solution.
Visualization methods for high-resolution, transient, 3-D, finite element situations
Christon, M.A.
1995-01-10T23:59:59.000Z
Scientific visualization is the process whereby numerical data is transformed into a visual form to augment the process of discovery and understanding. Visualizing the data generated by large-scale, transient, three-dimensional finite element simulations poses many challenges due to geometric complexity, the presence of multiple materials and multiple element types, and the inherent unstructured nature of the meshes. In this paper, the direct use of finite element data structures, nodal assembly procedures, and element interpolants for volumetric adaptive surface extraction, surface rendering, vector grids and particle tracing is discussed. A brief description of a {open_quotes}direct-to-disk{close_quotes} animation system is presented, and case studies which demonstrate the use of isosurfaces, vector plots, cutting planes, reference surfaces and particle tracing are then discussed in the context of several case studies for transient incompressible viscous flow, and acoustic fluid-structure interaction simulations. An overview of the implications of massively parallel computers on visualization is presented to highlight the issues in parallel visualization methodology, algorithms. data locality and the ultimate requirements for temporary and archival data storage and network bandwidth.
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
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
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.
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;
Victoria, University of
Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis by Patricio Andres Lillo experienced in candi- date Canadian wind turbine deployment locations. The thesis then narrows its focus
Determining finite volume elements for the 2D Navier-Stokes equations
Jones, D.A. (California Univ., Irvine, CA (United States). Dept. of Mathematics); Titi, E.S. (California Univ., Irvine, CA (United States). Dept. of Mathematics Cornell Univ., Ithaca, NY (United States). Mathematical Sciences Inst.)
1991-01-01T23:59:59.000Z
We consider the 2D Navier-Stokes equations on a square with periodic boundary conditions. Dividing the square into N equal subsquares, we show that if the asymptotic behavior of the average of solutions on these subsquares (finite volume elements) is known, then the large time behavior of the solution itself is completely determined, provided N is large enough. We also establish a rigorous upper bound for N needed to determine the solutions to the Navier-Stokes equation in terms of the physical parameters of the problem. 34 refs.
Numerical solution of 2-D nonlinear inverse heat conduction problems using finite-element techniques
Khachfe, R.A.; Jarny, Y.
2000-02-01T23:59:59.000Z
A general method is presented for solving different classes of nonlinear inverse heat conduction problems (IHCP) for two-dimensional, arbitrarily shaped bodies. It is based on the systematic use of a finite-element library. It is shown that, following this approach, the conjugate gradient method can be easily implemented. The method offers a very wide field of practical applications in inverse thermal analysis, while reducing very significantly the amount of work which remains specific for each particular IHPC. Two numerical experiments illustrate the influence of data errors and the iterative regularization principle.
Large-Scale Parallel Finite Element Analysis of the Stress Singular Problems
Noriyuki Kushida; Hiroshi Okuda; Genki Yagawa [University of Tokyo (Japan)
2002-07-01T23:59:59.000Z
In this paper, the convergence behavior of large-scale parallel finite element method for the stress singular problems was investigated. The convergence behavior of iterative solvers depends on the efficiency of the pre-conditioners. However, efficiency of pre-conditioners may be influenced by the domain decomposition that is necessary for parallel FEM. In this study the following results were obtained: Conjugate gradient method without preconditioning and the diagonal scaling preconditioned conjugate gradient method were not influenced by the domain decomposition as expected. symmetric successive over relaxation method preconditioned conjugate gradient method converged 6% faster as maximum if the stress singular area was contained in one sub-domain. (authors)
Permeability computation on a REV with an immersed finite element method
Laure, P. [Laboratoire J.-A. Dieudonne, CNRS UMR 6621, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, Cedex 02 (France); Puaux, G.; Silva, L.; Vincent, M. [MINES ParisTech, CEMEF-Centre de Mise en Forme des Materiaux, CNRS UMR 7635, BP 207 1 rue Claude, Daunesse 06904 Sophia Antipolis cedex (France)
2011-05-04T23:59:59.000Z
An efficient method to compute permeability of fibrous media is presented. An immersed domain approach is used to represent the porous material at its microscopic scale and the flow motion is computed with a stabilized mixed finite element method. Therefore the Stokes equation is solved on the whole domain (including solid part) using a penalty method. The accuracy is controlled by refining the mesh around the solid-fluid interface defined by a level set function. Using homogenisation techniques, the permeability of a representative elementary volume (REV) is computed. The computed permeabilities of regular fibre packings are compared to classical analytical relations found in the bibliography.
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.
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...
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.
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
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.
Glass, Micheal W.; Hogan, Roy E., Jr.; Gartling, David K.
2010-03-01T23:59:59.000Z
The need for the engineering analysis of systems in which the transport of thermal energy occurs primarily through a conduction process is a common situation. For all but the simplest geometries and boundary conditions, analytic solutions to heat conduction problems are unavailable, thus forcing the analyst to call upon some type of approximate numerical procedure. A wide variety of numerical packages currently exist for such applications, ranging in sophistication from the large, general purpose, commercial codes, such as COMSOL, COSMOSWorks, ABAQUS and TSS to codes written by individuals for specific problem applications. The original purpose for developing the finite element code described here, COYOTE, was to bridge the gap between the complex commercial codes and the more simplistic, individual application programs. COYOTE was designed to treat most of the standard conduction problems of interest with a user-oriented input structure and format that was easily learned and remembered. Because of its architecture, the code has also proved useful for research in numerical algorithms and development of thermal analysis capabilities. This general philosophy has been retained in the current version of the program, COYOTE, Version 5.0, though the capabilities of the code have been significantly expanded. A major change in the code is its availability on parallel computer architectures and the increase in problem complexity and size that this implies. The present document describes the theoretical and numerical background for the COYOTE program. This volume is intended as a background document for the user's manual. Potential users of COYOTE are encouraged to become familiar with the present report and the simple example analyses reported in before using the program. The theoretical and numerical background for the finite element computer program, COYOTE, is presented in detail. COYOTE is designed for the multi-dimensional analysis of nonlinear heat conduction problems. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in COYOTE are also outlined. Instructions for use of the code are documented in SAND2010-0714.
Kais, Sabre
initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, and an "exact" formulation using FEM. We then use the FSS approach to determine its critical nuclear chargePHYSICAL REVIEW E 85, 036706 (2012) Finite-size scaling for quantum criticality using the finite
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.
Finite element analysis of the Arquin-designed CMU wall under a dynamic (blast) load.
Lopez, Carlos; Petti, Jason P.
2008-12-01T23:59:59.000Z
The Arquin Corporation designed a CMU (concrete masonry unit) wall construction and reinforcement technique that includes steel wire and polymer spacers that is intended to facilitate a faster and stronger wall construction. Since the construction method for an Arquin-designed wall is different from current wall construction practices, finite element computer analyses were performed to estimate the ability of the wall to withstand a hypothetical dynamic load, similar to that of a blast from a nearby explosion. The response of the Arquin wall was compared to the response of an idealized standard masonry wall exposed to the same dynamic load. Results from the simulations show that the Arquin wall deformed less than the idealized standard wall under such loading conditions. As part of a different effort, Sandia National Laboratories also looked at the relative static response of the Arquin wall, results that are summarized in a separate SAND Report.
Higher-Order Spectral/HP Finite Element Technology for Structures and Fluid Flows
Vallala, Venkat Pradeep
2013-06-20T23:59:59.000Z
This study deals with the use of high-order spectral/hp approximation functions in the ?nite element models of various nonlinear boundary-value and initial-value problems arising in the ?elds of structural mechanics and ?ows of viscous...
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...
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
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
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
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
Antoine, Xavier - Institut de MathÃ©matiques Ã?lie Cartan, UniversitÃ© Henri PoincarÃ©
Keywords: Acoustic scattering Finite element Plane wave Pollution High-frequency Artificial boundary condition in acoustic scattering R. Kechroud a , A. Soulaimani a , X. Antoine b,c,* a Ã?cole de Technologie are found. Indeed, it is well known that pollution effects [10Â12] arise in the standard FEM, limiting its
Beaumont, Christopher
SOPALE (a finite-element computer code for the computation of visco-plastic creeping flows are bracketed like this ** 1. What is SOPALE? SOPALE is a computer code written in Fortran 77 which computes of the code history and contributors ** my comments, which may be eliminated or used at your discretion
Boyer, Edmond
of steel continuous casting Michel Bellet, Alban Heinrich Ecole des Mines de Paris, Centre de Mise en Forme.bellet@ensmp.fr Synopsis This paper addresses the two-dimensional finite element simulation of steel continuous casting state (temperature, deformation, stresses) of steel all along the continuous casting machine. Both plane
Lopez-Pamies, Oscar
A finite element approach to study cavitation instabilities in non-linear elastic solids under a b s t r a c t This paper proposes an effective numerical method to study cavitation instabilities a single infinitesimal defect at its center. The occurrence of cavitation is identified as the event when
Mofrad, Mohammad R. K.
number mass/heat transport in a fully developed pipe flow. Ó 2002 Elsevier Science B.V. All rights of physics and engineering. Examples are heat transfer processes in rubber extrusion, plastic castingA characteristic/finite element algorithm for time-dependent 3-D advection-dominated transport
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.
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
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 ...
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).
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.
Hossain, Mohammad Kabir
1990-01-01T23:59:59.000Z
FINITE ELEMENT ANALYSIS AND DESiGN OF LARGE DIANETER FLEXIBLE VERTICAL PIPES SUBJECTED TO INCREMENTAL COMPACTED BACKFILL LOADS AND CREEP EFFECTS A Thesis by MOHAMMAD KABIR HOSSAIN Submitted to the Office of Graduate Studies of Texas A... BACKFILL LOADS AND CREEP EFFECTS A Thesis by MOHAMMAD KABIR HOSSAIN Approved as to sty1e and content by: R be+r L. Lytton (Chair of Committee) Ozden 0. Ochoa (Member) Derek V. Morris (Member) ames T P Yao (Head of rtment) ABSTRACT Finite...
Finite element based micromechanical modeling of periodic composite microstructures
Rosario, Matthew J
2010-01-01T23:59:59.000Z
The mechanical behavior of cellular solids, including stiffness and strength, can be tuned by tailoring the underlying geometry and material constituents of the microstructure. Here the effect of key parameters on the ...
Finite element modeling of SHTE and PSVTM electroseismics
zyserman
reduction of the electroseismic effect in porous media with strong electrolytic concentration was reported by Lorne et al. (1999); Haines and Pride (2006),.
A Mixed Finite Element Framework for Modeling Coupled Fluid Flow ...
Birendra Jha
2005-10-03T23:59:59.000Z
and in enhanced oil recovery techniques such as steam assisted gravity ..... When fluid flows through a porous medium there are three forces acting, per unit.
Finite element modeling of hydraulic fracturing in 3D
2013-03-22T23:59:59.000Z
Mar 22, 2013 ... Gautier. A.. Touzelet. S.: Tracer testing of the geothermal heat ex- ... R.: A field demonstra- tion of hydraulic fracturing for solid waste diposal—.
Finite element modeling of heat and mass transport in aquifers
Grubaugh, Elston Kent
1980-01-01T23:59:59.000Z
1s written as v [ ' ( ? + pg ? )] + 0 = (o + ep a ) ? + ez a ? !I) kxi o ap aT ax, ax; o p at o T at where kx. 1 Po Bp 9T intr1nsic permeab1lity in the x. direct1on, L ; 2. 1 fluid density, M L -2. fluid dynamic v1scos1ty, FTL 2 -l... The basis functions used here are presented in Table 1. These functions fulfill both the compatibility and completeness requirements Linear Nodes le 5r lo Quadratic Nodes 13 I 820 9 I I l7 J Ig ~ I8 l4 19 23 24 Cubic Nodes 37 38 30 39 743...
Finite element modeling of flow through ceramic pot filters
Kelly, Anna C
2013-01-01T23:59:59.000Z
Pure Home Water (PHW) is an organization based in Tamale, Ghana that manufactures and distributes ceramic water filters. While many ceramic filter factories manufacture flowerpot-shaped filters, PHW has transitioned from ...
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.
Test of modified BCS model at finite temperature
V. Yu. Ponomarev; A. I. Vdovin
2005-08-24T23:59:59.000Z
A recently suggested modified BCS (MBCS) model has been studied at finite temperature. We show that this approach does not allow the existence of the normal (non-superfluid) phase at any finite temperature. Other MBCS predictions such as a negative pairing gap, pairing induced by heating in closed-shell nuclei, and ``superfluid -- super-superfluid'' phase transition are discussed also. The MBCS model is tested by comparing with exact solutions for the picket fence model. Here, severe violation of the internal symmetry of the problem is detected. The MBCS equations are found to be inconsistent. The limit of the MBCS applicability has been determined to be far below the ``superfluid -- normal'' phase transition of the conventional FT-BCS, where the model performs worse than the FT-BCS.
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.
Shadmand, Mohammad
2012-07-16T23:59:59.000Z
A DESIGN-ORIENTED FRAMEWORK TO DETERMINE THE PARASITIC PARAMETERS OF HIGH FREQUENCY MAGNETICS IN SWITCING POWER SUPPLIES USING FINITE ELEMENT ANALYSIS TECHNIQUES A Thesis by MOHAMMAD BAGHER SHADMAND Submitted to the Office... to Determine the Parasitic Parameters of High Frequency Magnetics in Switching Power Supplies using Finite Element Analysis Techniques Copyright 2012 Mohammad Bagher Shadmand A DESIGN-ORIENTED FRAMEWORK TO DETERMINE THE PARASITIC PARAMETERS OF HIGH...
Yaqi Wang; Jean C. Ragusa
2011-10-01T23:59:59.000Z
Diffusion synthetic acceleration (DSA) schemes compatible with adaptive mesh refinement (AMR) grids are derived for the SN transport equations discretized using high-order discontinuous finite elements. These schemes are directly obtained from the discretized transport equations by assuming a linear dependence in angle of the angular flux along with an exact Fick's law and, therefore, are categorized as partially consistent. These schemes are akin to the symmetric interior penalty technique applied to elliptic problems and are all based on a second-order discontinuous finite element discretization of a diffusion equation (as opposed to a mixed or P1 formulation). Therefore, they only have the scalar flux as unknowns. A Fourier analysis has been carried out to determine the convergence properties of the three proposed DSA schemes for various cell optical thicknesses and aspect ratios. Out of the three DSA schemes derived, the modified interior penalty (MIP) scheme is stable and effective for realistic problems, even with distorted elements, but loses effectiveness for some highly heterogeneous configurations. The MIP scheme is also symmetric positive definite and can be solved efficiently with a preconditioned conjugate gradient method. Its implementation in an AMR SN transport code has been performed for both source iteration and GMRes-based transport solves, with polynomial orders up to 4. Numerical results are provided and show good agreement with the Fourier analysis results. Results on AMR grids demonstrate that the cost of DSA can be kept low on locally refined 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, 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
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
Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables
Kumar, Ratnesh
1 Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables for reactive untimed infinite state systems called input- output extended finite automaton (I/O-EFA), which of a finite bisimilar abstraction. The results are illustrated through examples that model reactive software
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.
McArthur, Karl Edward
1996-01-01T23:59:59.000Z
calibrated to a June 1991 data set from a TWDB intensive inflow survey of the Laguna Madre. Velocity and water quality data were available for the three days of the survey. Tide data for a much longer period were available from TCOON network stations...
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.
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...
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...
THE MORTAR FINITE ELEMENT METHOD FOR 3D MAXWELL EQUATIONS: FIRST RESULTS
Buffa, Annalisa
of the mortar element method to the numerical solution of Maxwell's equations (in wave form) by H; accepted for publication (in revised form) February 2, 2001; published electronically July 31, 2001. This work has been partially supported by Istituto di Analisi Numerica del Centro Nazionale delle Ricerche
Finite-Volume Spectra of the Lee-Yang Model
Zoltan Bajnok; Omar el Deeb; Paul A. Pearce
2014-12-29T23:59:59.000Z
We consider the non-unitary Lee-Yang minimal model ${\\cal M}(2,5)$ in three different finite geometries: (i) on the interval with integrable boundary conditions labelled by the Kac labels $(r,s)=(1,1),(1,2)$, (ii) on the circle with periodic boundary conditions and (iii) on the periodic circle including an integrable purely transmitting defect. We apply $\\varphi_{1,3}$ integrable perturbations on the boundary and on the defect and describe the flow of the spectrum. Adding a $\\Phi_{1,3}$ integrable perturbation to move off-criticality in the bulk, we determine the finite size spectrum of the massive scattering theory in the three geometries via Thermodynamic Bethe Ansatz (TBA) equations. We derive these integral equations for all excitations by solving, in the continuum scaling limit, the TBA functional equations satisfied by the transfer matrices of the associated $A_{4}$ RSOS lattice model of Forrester and Baxter in Regime III. The excitations are classified in terms of $(m,n)$ systems. The excited state TBA equations agree with the previously conjectured equations in the boundary and periodic cases. In the defect case, new TBA equations confirm previously conjectured transmission factors.
Constraints of mixing matrix elements in the sequential fourthgeneration model
W. J. Huo
2002-03-23T23:59:59.000Z
We review our works on the sequential fourth generation model and focus on the constriants of $4\\times 4$ quark mixing matrix elements. We investigate the quark mixing matrix elements from the rare $K,B$ meson decays. We talk about the $ hierarchy$ of the $4\\times 4$ matrix and the existence of fourth generation.
Lipnikov, Konstantin [Los Alamos National Laboratory; Agouzal, Abdellatif [UNIV DE LYON; Vassilevski, Yuri [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
We present a new technology for generating meshes minimizing the interpolation and discretization errors or their gradients. The key element of this methodology is construction of a space metric from edge-based error estimates. For a mesh with N{sub h} triangles, the error is proportional to N{sub h}{sup -1} and the gradient of error is proportional to N{sub h}{sup -1/2} which are optimal asymptotics. The methodology is verified with numerical experiments.
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...
Everstine, Gordon C.
be applied easily to existing NASTRAN models of complex machinery structural systems, and outputs power ELEMENT PREDICTIONS AND EXPERIMENTAL MEASUREMENTS OF STRUCTUREBORNE POWERS IN A TSHAPED BEAM Stephen A 200845000 INTRODUCTION Based on initial structureborne power studies for Tshaped beams presented
Extending ballistic graphene FET lumped element models to diffusive devices
Paris-Sud XI, Université de
Extending ballistic graphene FET lumped element models to diffusive devices G Vincenzi1,2 , G graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced
Superconvergence of finite element approximations by a computer-based approach
Gangaraj, Srihari Kumar
1994-01-01T23:59:59.000Z
. Superconvcrgence poi?ts I'or I, hc & lass of "harmonic" solutious of the cquatio?s of pla?c elasl i& i ty: Cubi& i& n?dipitv square elements The superconvergence points arc le& atcd at the intersection of thc contours C a?' (P; f, T), i = 1, . . . , 4... of &he mat('ri;&I orl, l&ot ropy. Sup( r(o?v& rgcuce points fol the r& curl]po?eut of thc Ih&s, &I&('u) I'o&. tl&& ?lais of "harmonic" solutions of th&. cquatio? ol' or&i&olropi& h( &I, -&. ond?ction: Cubic serendipity ele&?cnts. /cro-co?to?rs a?d s...
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.
Finite Element Studies in the Out-Of-Plane Failure of Unreinfored Masonry
Martini, Kirk
, modelling phenomena resulting from different elastic properties of block and mortar. Â· Joints and associated local effects at the block-mortar interface, instead model- ling the mortar joints as potential lines of failure due to cracking. Â· Joints are smeared out. In this approach, the block-mortar composite
Navon, Michael
, Reduced order modelling, Shock wave. 1. Introduction Reduced Order Model (ROM) technology is a rapidly to extract a set of modes characteristic of the database which constitutes the optimal basis energy of the flow. The leading POD modes are not able to dissipate enough energy since the main amount
A STABILIZED FINITE VOLUME ELEMENT FORMULATION FOR SEDIMENTATION-CONSOLIDATION PROCESSES
Bürger, Raimund
¨URGER, RICARDO RUIZ-BAIER, AND H´ECTOR TORRES Abstract. A model of sedimentation-consolidation processes in so.1. Scope. The sedimentation of a suspension of small solid particles dispersed in a viscous fluid under or naturally and form sediment layers that undergo consolidation. The modeling and simulation of the resulting
Tezduyar, Tayfun E.
the sediment transport, the dispersion of contaminants, the exchange of sea water and so on accurately for the shallow water ¯ow based on the two di- mensional model have been presented in the past. The present, it is necessary to evaluate the vertical velocity pro®le. Several quasi-three dimen- sional models have been also
MixedHybrid Finite Elements for the Simulation of Thermal Oxidation in Semiconductors
Causin, Paola
Cedex France b MOX Modeling and Scientific Computing, Dipartimento di Matematica ``F Email address: Riccardo.Sacco@mate.polimi.it (Riccardo Sacco). URL: mox.polimi.it (Riccardo Sacco
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...
A finite element Poisson solver for gyrokinetic particle simulations in a global field aligned mesh
Lin, Zhihong
and thus a logically non-rectangular grid in a general geometry. Employing test cases where the analytical size employing portable, extensible toolkit for scientific computation (PETSc) to solve the sparse models for global electromagnetic simulations. Ó 2005 Elsevier Inc. All rights reserved. PACS: 52.30.Gz
A CONVERGENT ADAPTIVE FINITE ELEMENT METHOD FOR AN OPTIMAL DESIGN PROBLEM
Bartels, Soeren
of given geometry and unknown distribution of two materials of prescribed amounts is one model example in topology optimisation. It eventually leads to a degenerated convex minimisation problem. The numerical to refine everywhere. Its convergence proof is therefore based on energy estimates and some refined
Varghese, Julian
2010-10-12T23:59:59.000Z
. In addition to implementing an oxidation model, the framework was also used to implement strategies that expedited the simulation of oxidation in textile composites so that it would take only a few hours. The simulation showed that the tow architecture played...
Tubular Links for Eccentrically Braced Frames. I: Finite Element Parametric Study
Bruneau, Michel
, making them less susceptible to lateral torsional buckling, thereby reducing or eliminating the need levels prior to significant strength degradation from local buckling. Part B of the study involves models shapes as link beams necessitates that they be braced out-of-plane to prevent lateral torsional buck
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
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
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
A simple Discrete-Element-Model of Brazilian Test
Sumanta Kundu; Anna Stroisz; Srutarshi Pradhan
2015-03-30T23:59:59.000Z
We present a statistical model which is able to capture some interesting features exhibited in the Brazilian test. The model is based on breakable elements which break when the force experienced by the elements exceed their own load capacity. In this model when an element breaks, the capacity of the neighboring elements are decreased by a certain amount assuming weakening effect around the defected zone. We numerically investigate the stress-strain behavior, the strength of the system, how it scales with the system size and also it's fluctuation for both uniformly and weibull distributed breaking threshold of the elements in the system. We find that the strength of the system approaches it's asymptotic value $\\sigma_c=1/6$ and $\\sigma_c=5/18$ for uniformly and Weibull distributed breaking threshold of the elements respectively. We have also shown the damage profile right at the point when the stress-strain curve reaches at it's maximum and then it is compared with our experimental observations.
Discrete-element model for the interaction between ocean waves and sea ice
Xu, Zhijie; Tartakovsky, Alexandre M.; Pan, Wenxiao
2012-01-05T23:59:59.000Z
We present a discrete element method (DEM) model to simulate the mechanical behavior of sea ice in response to ocean waves. The wave/ice interaction can potentially lead to the fracture and fragmentation of sea ice depending on the wave amplitude and period. The fracture behavior of sea ice is explicitly modeled by a DEM method, where sea ice is modeled by densely packed spherical particles with finite size. These particles are bonded together at their contact points through mechanical bonds that can sustain both tensile & compressive forces and moments. Fracturing can be naturally represented by the sequential breaking of mechanical bonds. For a given amplitude and period of incident ocean wave, the model provides information for the spatial distribution and time evolution of stress and micro-fractures and the fragment size distribution. We demonstrate that the fraction of broken bonds,, increases with increasing wave amplitude. In contrast, the ice fragment size decreases with increasing amplitude.
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...
Finite-element analysis of the deformation of thin Mylar films due to measurement forces.
Baker, Michael Sean; Robinson, Alex Lockwood; Tran, Hy D.
2012-01-01T23:59:59.000Z
Significant deformation of thin films occurs when measuring thickness by mechanical means. This source of measurement error can lead to underestimating film thickness if proper corrections are not made. Analytical solutions exist for Hertzian contact deformation, but these solutions assume relatively large geometries. If the film being measured is thin, the analytical Hertzian assumptions are not appropriate. ANSYS is used to model the contact deformation of a 48 gauge Mylar film under bearing load, supported by a stiffer material. Simulation results are presented and compared to other correction estimates. Ideal, semi-infinite, and constrained properties of the film and the measurement tools are considered.
Finite element analysis of conjugate heat transfer in axisymmetric pipe flows
Fithen, Robert Miller
1987-01-01T23:59:59.000Z
with no axial fluid conduction, such as liquid water at a moderate to high Reynolds number. Detailed fluid ? solid interface heat flux, Nusselt number, wall, and bulk temperatures for each case are presented. The results indicate axial wall conduction is very... model for a circular tube Comparison for constant heat flux case Comparison for constant temperature case Heat flux for Pe=5, constant heat flux case Heat flux for Pe=50, constant heat flux case Heat flux for Pe=200, constant heat flux case Heat...
Ariza Moreno, Pilar
SEMINARIOS INTERUNIVERSITARIOS MECÁNICA Y MATERIALES STRUCTURAL MODELING OF BIOSOLIDS UNDER FINITE the detailed structure of a biosolid in a material model. We focus on the micro- structure of arterial walls
Mahinthakumar, K.
1997-01-01T23:59:59.000Z
In this report we present parallel solvers for large linear systems arising from the finite-element discretization of the three-dimensional steady-state groundwater flow problem. Our solvers are based on multigrid and Krylov subspace methods. The parallel implementation is based on a domain decomposition strategy with explicit message passing using NX and MPI libraries. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors and on other parallel platforms such as SGI/Power Challenge Array, Cray/SGI Origin 2000, Convex Exemplar SPP-1200, and IBM SP using up to 64 processors. We show that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 70 million nodes in less than a minute. This is more than 25 times faster than the diagonal preconditioned conjugate gradient method which is one of the more popular methods for large sparse linear systems. Our results also show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov subspace method such as the conjugate gradient method. We show that even for extremely heterogeneous systems the multigrid pre-conditioned conjugate gradient method is at least 10 times faster than the diagonally preconditioned conjugate gradient method.
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.
Pask, J E; Sukumar, N; Guney, M; Hu, W
2011-02-28T23:59:59.000Z
Over the course of the past two decades, quantum mechanical calculations have emerged as a key component of modern materials research. However, the solution of the required quantum mechanical equations is a formidable task and this has severely limited the range of materials systems which can be investigated by such accurate, quantum mechanical means. The current state of the art for large-scale quantum simulations is the planewave (PW) method, as implemented in now ubiquitous VASP, ABINIT, and QBox codes, among many others. However, since the PW method uses a global Fourier basis, with strictly uniform resolution at all points in space, and in which every basis function overlaps every other at every point, it suffers from substantial inefficiencies in calculations involving atoms with localized states, such as first-row and transition-metal atoms, and requires substantial nonlocal communications in parallel implementations, placing critical limits on scalability. In recent years, real-space methods such as finite-differences (FD) and finite-elements (FE) have been developed to address these deficiencies by reformulating the required quantum mechanical equations in a strictly local representation. However, while addressing both resolution and parallel-communications problems, such local real-space approaches have been plagued by one key disadvantage relative to planewaves: excessive degrees of freedom (grid points, basis functions) needed to achieve the required accuracies. And so, despite critical limitations, the PW method remains the standard today. In this work, we show for the first time that this key remaining disadvantage of real-space methods can in fact be overcome: by building known atomic physics into the solution process using modern partition-of-unity (PU) techniques in finite element analysis. Indeed, our results show order-of-magnitude reductions in basis size relative to state-of-the-art planewave based methods. The method developed here is completely general, applicable to any crystal symmetry and to both metals and insulators alike. We have developed and implemented a full self-consistent Kohn-Sham method, including both total energies and forces for molecular dynamics, and developed a full MPI parallel implementation for large-scale calculations. We have applied the method to the gamut of physical systems, from simple insulating systems with light atoms to complex d- and f-electron systems, requiring large numbers of atomic-orbital enrichments. In every case, the new PU FE method attained the required accuracies with substantially fewer degrees of freedom, typically by an order of magnitude or more, than the current state-of-the-art PW method. Finally, our initial MPI implementation has shown excellent parallel scaling of the most time-critical parts of the code up to 1728 processors, with clear indications of what will be required to achieve comparable scaling for the rest. Having shown that the key remaining disadvantage of real-space methods can in fact be overcome, the work has attracted significant attention: with sixteen invited talks, both domestic and international, so far; two papers published and another in preparation; and three new university and/or national laboratory collaborations, securing external funding to pursue a number of related research directions. Having demonstrated the proof of principle, work now centers on the necessary extensions and optimizations required to bring the prototype method and code delivered here to production applications.
Bhardwaj, Rajneesh; Attinger, Daniel
2010-01-01T23:59:59.000Z
The objective of this work is to investigate the coupling of fluid dynamics, heat transfer and mass transfer during the impact and evaporation of droplets on a heated solid substrate. A laser-based thermoreflectance method is used to measure the temperature at the solid-liquid interface, with a time and space resolution of 100 {\\mu}s and 20 {\\mu}m, respectively. Isopropanol droplets with micro- and nanoliter volumes are considered. A finite-element model is used to simulate the transient fluid dynamics and heat transfer during the droplet deposition process, considering the dynamics of wetting as well as Laplace and Marangoni stresses on the liquid-gas boundary. For cases involving evaporation, the diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary condition for the evaporative flux at the droplet-air interface. High-speed visualizations are performed to provide matching parameters for the wetting model used in the simulations. Numerical and experimental results are compar...
Model calculations of nuclear data for biologically-important elements
Chadwick, M.B.; Blann, M.; Reffo, G. [Lawrence Livermore National Lab., CA (United States); Young, P.G. [Los Alamos National Lab., NM (United States)
1994-05-01T23:59:59.000Z
We describe calculations of neutron-induced reactions on carbon and oxygen for incident energies up to 70 MeV, the relevant clinical energy in radiation neutron therapy. Our calculations using the FKK-GNASH, GNASH, and ALICE codes are compared with experimental measurements, and their usefulness for modeling reactions on biologically-important elements is assessed.
Canonical Modelling of Relative Spacecraft Motion via Epicyclic Orbital Elements
Canonical Modelling of Relative Spacecraft Motion via Epicyclic Orbital Elements N. Jeremy Kasdin of canonical coordinates for the relative state-space dynamics. The Hamiltonian formulation facilitates to be examined via variational equations such as Lagrange's planetary equations (LPEs) or Gauss's variational
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 ...
Conde, J. C.; Chiussi, S.; Gontad, F.; Gonzalez, P. [Dpto. Fisica Aplicada, University of Vigo, E-36310 Vigo (Spain); Martin, E. [Dpto. Mecanica, Maquinas, Motores Termicos y Fluidos, University of Vigo, E-36310 Vigo (Spain); Serra, C. [CACTI, University of Vigo, E-36310 Vigo (Spain)
2010-07-05T23:59:59.000Z
Ultraviolet (UV) Excimer laser assisted processing is an alternative strategy for producing patterned silicon germanium heterostructures. We numerically analyzed the effects caused by pulsed 193 Excimer laser radiation impinging on patterned amorphous hydrogenated silicon (a-Si:H) and germanium (a-Ge:H) bilayers deposited on a crystalline silicon substrate [Si(100)]. The proposed two dimensional axisymmetric numerical model allowed us to estimate the temperature and concentration gradients caused by the laser induced rapid melting and solidification processes. Energy density dependence of maximum melting depth and melting time evolution as well as three dimensional temperature and element distribution have been simulated and compared with experimentally obtained results.
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.
Ris-R-1501(EN) Development of a user element in
Mikkelsen for all the help and discussions about finite element analysis and ABAQUS. 4 #12;1 Introduction implemented into an interface element in the UEL user subroutine in the finite element code ABAQUS. ComparisonRisÃ¸-R-1501(EN) Development of a user element in ABAQUS for modelling of cohesive laws in composite
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.
Biffle, J.H.; Blanford, M.L.
1994-05-01T23:59:59.000Z
JAC2D is a two-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 equations. The method is implemented in a two-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. A four-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.
Preece, D.S.; Stone, C.M.
1982-08-01T23:59:59.000Z
An increasing interest is being shown worldwide in using leached salt caverns to store oil and natural gas. A critical factor in the use of existing caverns and the design of new ones is the creep behavior of the salt surrounding the caverns. An understanding of this behavior is being gained by using laboratory triaxial creep data as material property input to finite element computer programs designed to calculate displacements and stresses due to creep. An important step in verifying these predictive methods is the comparison of field data from existing caverns with finite element analyses which incorporate the material properties and geometry of each site. This comparison has been made for caverns in the Eminence Dome (Mississippi), West Hackberry Dome (Louisiana), and Bayou Chocktaw Dome (Louisiana) with reasonably good correlation being obtained between measured and predicted volumetric response of the caverns. These comparisons are discussed in this paper.
Elander, Nils [Department of Physics, Stockholm University, Alba Nova University Center, SE-106 91 Stockholm (Sweden); Levin, Sergey [Department of Physics, Stockholm University, Alba Nova University Center, SE-106 91 Stockholm (Sweden); Institute for Physics, St. Petersburg University, Uljanovskaya 1, St. Petersburg 198904 (Russian Federation); Institute for Theoretical Atomic and Molecular Physics at Harvard University and Smithsonian Astrophysical Observatory, 60 Garden Street, MS 14 Cambridge, Massachusetts 02138 (United States); Yarevsky, Evgeny [Institute for Physics, St. Petersburg University, Uljanovskaya 1, St. Petersburg 198904 (Russian Federation); International Solvay Institutes for Physics and Chemistry, Case Postale 231, Campus Plaine ULB Boulevard du Triomphe, Brussels 1050 (Belgium)
2003-06-01T23:59:59.000Z
A technique based on the total-angular-momentum representation the smooth exterior complex-scaling procedure, and the three-dimensional finite-element method, is applied to calculations of S, P, and D resonant, so-called doubly excited, states of the helium atom. The resonances are calculated with an accuracy better than 10{sup -5} a.u. The applicability of an extrapolation procedure to complex energies is analyzed.
Dash, Z.V.; Robinson, B.A.; Zyvoloski, G.A.
1997-07-01T23:59:59.000Z
The requirements, design, and verification and validation of the software used in the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multicomponent flow in porous media, are described. The test of the DOE Code Comparison Project, Problem Five, Case A, which verifies that FEHM has correctly implemented heat and mass transfer and phase partitioning, is also covered.
Cheng, Hao
2006-10-30T23:59:59.000Z
sensitivity computation of the streamline models with the versatility of finite-difference simulation was developed. Use of finite-difference simulation can account for complex physics. Finally, we developed an approach to history matching three-phase flow...
A Spectral Element Approach for Modeling of Wave-Based Structural Health Monitoring Systems
Schulte, Rolf T.; Fritzen, Claus-Peter [Institute of Mechanics and Control-Mechatronics, University of Siegen, Paul-Bonatz-Str. 9-11, 57076 Siegen (Germany)
2010-09-30T23:59:59.000Z
During the last decades, guided waves have shown great potential for Structural Health Monitoring (SHM) applications. These waves can be excited and sensed by piezoelectric elements that can be permanently attached onto a structure offering online monitoring capability. As the setup of wave based SHM systems may be very difficult and time consuming there is a growing demand for efficient simulation tools providing the opportunity to design wave based SHM systems in a virtual environment. As usually high frequency waves are used, the associated short wavelength leads to the necessity of a very dense mesh, which makes conventional finite elements not well suited for this purpose. Therefore a flat shell spectral element approach is presented in this contribution. By including electromechanical coupling an SHM system can be simulated entirely from actuator voltage to sensor voltage. The focus of this contribution is the analysis of the effect of delaminations on propagating waves. A forward increment Lagrange multiplier method is used to simulate contact within the delaminated area. A model validation is performed using measured data of an anisotropic CFRP-plate.
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
Buscaglia, Gustavo C.
Conservative one-dimensional finite volume discretization of a new cavitation model for piston Cavitation ElrodÂAdams model PistonÂrings a b s t r a c t This paper presents a conservative numerical implementation of a new cavitation model that is well suited for lubrication problems with cavitated regions
Isothermal model of ICF burn with finite alpha range treatment
Galloway, Conner Daniel (Conner Daniel Cross)
2009-01-01T23:59:59.000Z
A simple model for simulating deuterium tritium burn in inertial confinement fusion capsules is developed. The model, called the Isothermal Rarefaction Model, is zero dimensional (represented as ordinary differential ...
Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks
S. Athanassopoulos; E. Mavrommatis; K. A. Gernoth; J. W. Clark
2005-11-30T23:59:59.000Z
A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys
Beckermann, Christoph
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys KENT of hydrogen in the melt is developed to predict pore formation during the solidification of aluminum alloys by Lee et al.[3] Recent examples of porosity models for aluminum alloy castings, including the effect
Long Fibre Composite Modelling Using Cohesive User's Element
Kozak, Vladislav; Chlup, Zdenek [Institute of Physics of Material AS of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)
2010-09-30T23:59:59.000Z
The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.
Nellie Rajarova,
2010-07-14T23:59:59.000Z
disadvantage of classical variational methods is the difficulty in constructing the approximate functions for arbitrary domains. 1.4. Review of Weighted-Residual Methods Weighted-residual methods are those in which we seek approximate solutions using a... functions. The pth order interpolation function is given by )48.2( 1 2 1 1 2 1 221 2 21 T pp npp p kp g g g f f f...
Notes 01. Modeling of mechanical (lumped parameter) elements
San Andres, Luis
2008-01-01T23:59:59.000Z
Fundamental elements in mechanical systems: inertias, stiffness and damping elements. Equivalent spring coefficients and associated potential energy. Equivalent mass or inertia coefficients and associated kinetic energy. Equations of motion of a...
Finite-temperature order-disorder phase transition in a cluster model of decagonal tilings
Gähler, Franz
phase,2 because its phason degrees of freedom are frozen (locked). The high-temperature state is accordingly called unlocked phase. Here, the thermal energy is suffi- ciently high to excite the phasonFinite-temperature order-disorder phase transition in a cluster model of decagonal tilings Michael
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda , Daniel F. Martinb Abstract Continental scale marine ice sheets such as the present day West Antarctic Ice Sheet are strongly phenomenon of this kind is the migration of the grounding line -- the division between ice in contact
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes
Herbin, RaphaÃ¨le
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes Emily GallouÃ«t. This paper deals with the numerical simulation of the diffusion and assimilation by photosynthesis of CO2 medium, from experimental measurements of the pointwise value of internal CO2 concentration, giving some
S5 S5 S5 lacks the finite model property Dept. of Computer Science
Kurucz, Agi
S5 × S5 × S5 lacks the finite model property A. Kurucz Dept. of Computer Science King's College London Abstract It follows from algebraic results of Maddux that every multi-modal logic L such that [S5, S5, . . . , S5] L S5n is undecidable, whenever n 3. This implies that the product logic S5×S5×S5
Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water
Kurganov, Alexander
Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water Alina Chertock of shallow water equations and the pollutant propagation is described by a transport equation. The idea and the pollution computations: the shallow water equations are numerically integrated using a #12;nite- volume
A finite difference model for predicting sediment oxygen demand in streams
Charbonnet, Danielle Andrea
2003-01-01T23:59:59.000Z
in the representative river system using benthic chambers. A finite difference model was developed based on Fick's Law of Diffusion. Mass transfer principles are used to perform a mass balance on the oxygen concentrations in the sediment in order to determine SOD...
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION
Eindhoven, Technische Universiteit
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION J. BRUINING AND C.J. VAN DUIJN Abstract. Steam drive recovery of oil is an economical way of producing oil even in times of low oil prices and is used world wide. This paper focuses on the one-dimensional setting, where steam
Bank, Randolph E.
Partial Di#11;erential Equations Randolph E. Bank #3; and Peter K. Jimack y Abstract We present a new domain decomposition algorithm for the parallel #12;nite element solution of elliptic partial di#11 to be utilized in a well load-balanced manner. Finally, numerical evidence is presented which suggests
Thermodynamics and fluctuations of conserved charges in Hadron Resonance Gas model in finite volume
Bhattacharyya, Abhijit; Samanta, Subhasis; Sur, Subrata
2015-01-01T23:59:59.000Z
The thermodynamics of hot and dense matter created in heavy-ion collision experiments are usually studied as a system of infinite volume. Here we report on possible effects for considering a finite system size for such matter in the framework of the Hadron Resonance Gas model. The bulk thermodynamic variables as well as the fluctuations of conserved charges are considered. We find that the finite size effects are insignificant once the observables are scaled with the respective volumes. The only substantial effect is found in the fluctuations of electric charge which may therefore be used to extract information about the volume of fireball created in heavy-ion collision experiments.
Thermodynamics and fluctuations of conserved charges in Hadron Resonance Gas model in finite volume
Abhijit Bhattacharyya; Rajarshi Ray; Subhasis Samanta; Subrata Sur
2015-02-03T23:59:59.000Z
The thermodynamics of hot and dense matter created in heavy-ion collision experiments are usually studied as a system of infinite volume. Here we report on possible effects for considering a finite system size for such matter in the framework of the Hadron Resonance Gas model. The bulk thermodynamic variables as well as the fluctuations of conserved charges are considered. We find that the finite size effects are insignificant once the observables are scaled with the respective volumes. The only substantial effect is found in the fluctuations of electric charge which may therefore be used to extract information about the volume of fireball created in heavy-ion collision experiments.
Constructing warm inflationary model in finite temperature BIon
M. R. Setare; A. Sepehri
2014-10-07T23:59:59.000Z
We study warm inflationary universe model on the BIon in thermal background. The BIon is a configuration in flat space of a D-brane and a parallel anti-D-brane connected by a wormhole with F-string charge. When the branes and antibranes are well separated and the brane's spike is far from the antibrane's spike, wormhole isn't formed however when two branes are close to each other, they can be connected by a wormhole. In this condition, there exists many channels for flowing energy from extra dimensions into our universe and inflation may naturally occur in a warm region. We present a model that allows all cosmological parameters like the scale factor $a$, the Hubble parameter $H$ and universe energy density depend on the shape function and temperature of wormhole in transverse dimension between two branes. In our model, the expansion of 4D universe is controlled by the thermal wormhole between branes and ends up in Big-Rip singularity. We show that at this singularity, universe would be destroyed and one black F-string formed. Finally, we test our model against WMAP, Planck and BICEP2 data and obtain the ripping time. According to experimental data, $N\\simeq 50$ case leads to $n_{s}\\simeq 0.96$, where \\emph{N} and $n_{s}$ are the number e-folds and the spectral index respectively. This standard case may be found in $0.01 data and $t_{rip}=27.5(Gyr)$ for BICEP2 data. Comparing this time with the time of Big Rip in brane-antibrane, we find that the wormhole in BIonic system accelerates the destruction of the universe.
Runtime system library for parallel finite difference models with nesting
Michalakes, J.
1997-03-01T23:59:59.000Z
RSL is a parallel run-time system library for implementing regular-grid models with nesting on distributed memory parallel computers. RSL provides support for automatically decomposing multiple model domains and for redistributing work between processors at run time for dynamic load balancing. A unique feature of RSL is that processor subdomains need not be rectangular patches; rather, grid points are independently allocated to processors, allowing more precisely balanced allocation of work to processors. Communication mechanisms are tailored to the application: RSL provides an efficient high-level stencil exchange operation for updating subdomain ghost areas and interdomain communication to support two-way interaction between nest levels. RSL also provides run-time support for local iteration over subdomains, global-local index translation, and distributed I/O from ordinary Fortran record-blocked data sets. The interface to RSL supports Fortran77 and Fortran90. RSL has been used to parallelize the NCAR/Penn State Mesoscale Model (MM5).
Winding Transitions at Finite Energy and Temperature: An O(3) Model
Salman Habib; Emil Mottola; Peter Tinyakov
1996-08-14T23:59:59.000Z
Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at low energies, and numerically for all energies up to the sphaleron scale. The Euclidean period beta of these finite energy instantons increases with energy, contrary to the behavior found in the abelian Higgs model or simple one dimensional systems. This results in a sharp crossover from instanton dominated tunneling to sphaleron dominated thermal activation at a certain critical temperature. Since this behavior is traceable to the soft breaking of conformal invariance by the mass term in the sigma model, semiclassical winding number transition amplitudes in the electroweak theory in 3+1 dimensions should exhibit a similar sharp crossover. We argue that this is indeed the case in the standard model for M_H < 4 M_W.
Structure of finite-RSB asymptotic Gibbs measures in the diluted spin glass models
Dmitry Panchenko
2015-02-25T23:59:59.000Z
We suggest a possible approach to proving the M\\'ezard-Parisi formula for the free energy in the diluted spin glass models, such as diluted K-spin or random K-sat model at any positive temperature. In the main contribution of the paper, we show that a certain small modification of the Hamiltonian in any of these models forces all finite-RSB asymptotic Gibbs measures in the sense of the overlaps to satisfy the M\\'ezard-Parisi ansatz for the distribution of spins. Unfortunately, what is still missing is a description of the general full-RSB asymptotic Gibbs measures. If one could show that the general case can be approximated by finite-RSB case in the right sense then one could a posteriori remove the small modification of the Hamiltonian to recover the M\\'ezard-Parisi formula for the original model.
Transport and dispersion of pollutants in surface impoundments: a finite difference model
Yeh, G.T.
1980-07-01T23:59:59.000Z
A surface impoundment model by finite-difference (SIMFD) has been developed. SIMFD computes the flow rate, velocity field, and the concentration distribution of pollutants in surface impoundments with any number of islands located within the region of interest. Theoretical derivations and numerical algorithm are described in detail. Instructions for the application of SIMFD and listings of the FORTRAN IV source program are provided. Two sample problems are given to illustrate the application and validity of the model.