Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01
Vijayaraghavan, A. (2005), “Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool” ABSTRACT DEFORM-
Modeling a bender element test using Abaqus Finite Element Program
Johnson, Sean (Sean Michael)
2011-01-01
Finite Element Methods hold promise for modeling the behavior of an unsaturated soil specimen subjected to bender element agitation. The immediate objective of this research project is to reproduce a bender element test ...
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
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
Finite element study of Lamb waves: modeling techniques and applications
Verdict, Gregory Scott
1993-01-01
and theoretical results. In addition, other finite element work shows the viability of using these modeling techniques as a tool for understanding the interaction of Lamb waves with physical defects. As a signal processing tool, neural networks will process...
Experimentally validated finite element model of electrocaloric multilayer ceramic structures
Smith, N. A. S. E-mail: maciej.rokosz@npl.co.uk Correia, T. M. E-mail: maciej.rokosz@npl.co.uk; Rokosz, M. K. E-mail: maciej.rokosz@npl.co.uk
2014-07-28
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.
Finite Element Model of Fracture Formation on Growing Surfaces
Prusinkiewicz, Przemyslaw
Finite Element Model of Fracture Formation on Growing Surfaces Pavol Federl and Przemyslaw-mail: federl|pwp@cpsc.ucalgary.ca Abstract We present a model of fracture formation on surfaces of bilayered materials. The model makes it possible to synthesize patterns of fractures induced by growth or shrinkage
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
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
Finite Element Modeling of Micromachined MEMS Photon Devices
Datskos, P.G.; Evans, B.M.; Schonberger, D.
1999-09-20
The technology of microelectronics that has evolved over the past half century is one of great power and sophistication and can now be extended to many applications (MEMS and MOEMS) other than electronics. An interesting application of MEMS quantum devices is the detection of electromagnetic radiation. The operation principle of MEMS quantum devices is based on the photoinduced stress in semiconductors, and the photon detection results from the measurement of the photoinduced bending. These devices can be described as micromechanical photon detectors. In this work, we have developed a technique for simulating electronic stresses using finite element analysis. We have used our technique to model the response of micromechanical photon devices to external stimuli and compared these results with experimental data. Material properties, geometry, and bimaterial design play an important role in the performance of micromechanical photon detectors. We have modeled these effects using finite element analysis and included the effects of bimaterial thickness coating, effective length of the device, width, and thickness.
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
2004-01-01
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
2012-12-20
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.
Progress in Developing Finite Element Models Replicating Flexural Graphite Testing
Robert Bratton
2010-06-01
This report documents the status of flexural strength evaluations from current ASTM procedures and of developing finite element models predicting the probability of failure. This work is covered under QLD REC-00030. Flexural testing procedures of the American Society for Testing and Materials (ASTM) assume a linear elastic material that has the same moduli for tension and compression. Contrary to this assumption, graphite is known to have different moduli for tension and compression. A finite element model was developed and demonstrated that accounts for the difference in moduli tension and compression. Brittle materials such as graphite exhibit significant scatter in tensile strength, so probabilistic design approaches must be used when designing components fabricated from brittle materials. ASTM procedures predicting probability of failure in ceramics were compared to methods from the current version of the ASME graphite core components rules predicting probability of failure. Using the ASTM procedures yields failure curves at lower applied forces than the ASME rules. A journal paper was published in the Journal of Nuclear Engineering and Design exploring the statistical models of fracture in graphite.
A Finite Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2013-11-02
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.
Spectral/hp Finite Element Models for Fluids and Structures
Payette, Gregory
2012-07-16
for the numerical simulation of the fully geometrically nonlinear mechanical response of isotropic, laminated composite and functionally graded elastic shell structures. In addition, we also present a simple and efficient sparse global finite element coefficient...
Surface photovoltage measurements and finite element modeling of SAW devices.
Donnelly, Christine
2012-03-01
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)
2012-07-01
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)
Calibration under uncertainty for finite element models of masonry monuments
Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin
2010-02-01
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.
Finite element modeling of SHTE and PSVTM electroseismics
Fabio I. Zyserman
2010-10-07
element method to model electric fields induced by acoustic waves in ...... homogeneous layer of water-saturated poorly permeable shale; the .... As in gas/
Integrated Modeling, Finite-Element Analysis, and Engineering Design for Thin-Shell
Schroeder, Peter
Integrated Modeling, Finite-Element Analysis, and Engineering Design for Thin-Shell Structures transfer between the geometric design and finite-element anal- ysis tools. No cumbersome remodeling.S.A. Abstract Many engineering design applications require geometric modeling and mechanical simulation of thin
Bangerth, Wolfgang
Adaptive finite element methods for forward modeling in fluorescence enhanced frequency domain for Subsurface Modeling, ICES, University of Texas, Austin, TX Abstract: An adaptive finite element scheme the boundary measurements of photon energy resulting from the tissue stimulation via infrared light sources
Mihaila, Bogdan
TO -URANIUM Marko Knezevic, Rodney J. McCabe, Ricardo A. Lebensohn, Carlos N. Tomé, and Bogdan Mihaila Keywords: Uranium; Constitutive modeling; Finite Element Method Abstract We present an improved mechanical response of wrought -uranium. In this regard, a finite element integration point is considered
On a tensor-based finite element model for the analysis of shell structures
Arciniega Aleman, Roman Augusto
2006-04-12
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 ...
Qapo, Michael; Dirar, Samir; Yang, Jian; Elshafie, Mohammed Z. E. B.
2014-12-16
This paper presents a three-dimensional nonlinear finite element (FE) model for prestressed concrete girders strengthened in shear with externally bonded carbon fibre reinforced polymer (CFRP) reinforcement. A total strain rotating crack model...
Harrison, Mark
1988-01-01
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
Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites
Gaddamanugu, Dhatri
2010-07-14
Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading...
Finite element decomposition and grid generation for brain modeling and visualization
Batte, David Allan
1997-01-01
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...
TEA - a linear frequency domain finite element model for tidal embayment analysis
Westerink, Joannes J.
1984-01-01
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 ...
3-D Finite-Element Modelling of Magnetotelluric Data With a Static Divergence Correction
Farquharson, Colin G.
correction #12;Standard Finite-Element Modelling: Results 1e-14 1e-131e-13 1e-12 1e-11 1e-10 1e-09 1e-08 1e.1 Hz, without correction #12;Standard Finite-Element Modelling: Results 1e-14 1e-131e-13 1e-12 1e-11 1e-Element Modelling With Correction: Results 1e-14 1e-131e-13 1e-12 1e-11 1e-10 1e-09 1e-08 1e-07 1e-06 1e-05 0.0001 0
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
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 is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering
Adaptive Finite Element Discretization of Flow Problems for Goal-Oriented Model Reduction
. The emphasis is on laminar viscous incompressible flows governed by the Navier-Stokes equations. But also computation in a laminar viscous fluid modeled by the sta- tionary Navier-Stokes equations for velocity vAdaptive Finite Element Discretization of Flow Problems for Goal-Oriented Model Reduction Rolf
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
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
Finite Element Solution of Optimal Control Problems Arising in Semiconductor Modeling
Siefert, Chris
- timization problem, especially for highly heterogeneous materials with large jumps in material properties. 1Finite Element Solution of Optimal Control Problems Arising in Semiconductor Modeling Pavel Bochev, and inverse problems arising in the modeling of semiconductor devices lead to optimization problems
A Finite-Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2014-09-01
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 Modelling Of Thermal Processes With Phase Transitions
Vuik, Kees
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 1D steady diffusion equation . . . . . . . . . . . . . . . . . . . . . 5 2.2.1 Weak matrix and vector . . . . . . . . . . 8 2.2.5 Boundary conditions and assembly . . . . . . . . . . . . . . . . . . . . . . . 14 2.3.5 Streamline Upwind Petrov Galerkin method . . . . . . . . 16 2.4 Linear elements in two
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01
T. (1999). Computational Geomechanics with Special ReferenceDynamic Problems in Geomechanics," PhD Thesis, Universityon Numerical Models in Geomechanics, G. N. Pande, Van Impe,
FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE FREQUENCIES
De Flaviis, Franco
#12;FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE@uci.edu The recent developments of microelectromechanical systems (MEMS) switch and their use at microwave frequencies have promoted exciting advancements in the field of microwave switching. In comparison with other
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
Artificial Neural Network and Finite Element Modeling of Nanoindentation Tests
Haj-Ali, Rami
for a given depth. Their FE hardness results and plastic flow properties of the individual constituents information for the ANN model to extract material flow properties of the indented material. I. INTRODUCTION. The cone shape THE strength, fatigue, and fracture properties of multi- is constrained to have the same
Analysis of a finite element formulation for modelling phase separation
Wells, G N; Garikipati, Krishna
2007-01-01
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...
Jackson, Jason R.
1996-01-01
Elastomers are becoming more prevalent in everyday products, and it is very important to be able to describe their behavior. Particularly, with advancements in computer hardware and software, the use of finite element ...
Ghosh, Somnath
A size-dependent crystal plasticity finite-element model for creep and load shedding Abstract A rate-dependent anisotropic elastic-crystal plasticity based finite-element (FE) model with size in the crystal plasticity relations are expressed as HallPetch type relations, where the grain size, lath size
A novel hybrid finite element model for modeling anisotropic composites Changyong Cao a
Qin, Qinghua
Composite materials Green's function Hybrid finite element Stroh formalism a b s t r a c t In this paper we-plane stiffness, bending stiffness, strength, and coef- ficient of thermal expansion (see Fig. 1) [1]. Individual layers (or laminae) of the laminates consist of high-modulus, high-strength fibers in a polymeric
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)
2011-06-23
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,
2012-01-01
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.
Mixed-RKDG Finite Element Methods for the 2-D Hydrodynamic Model for Semiconductor Device Simulation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chen, Zhangxin; Cockburn, Bernardo; Jerome, Joseph W.; Shu, Chi-Wang
1995-01-01
In this paper we introduce a new method for numerically solving the equations of the hydrodynamic model for semiconductor devices in two space dimensions. The method combines a standard mixed finite element method, used to obtain directly an approximation to the electric field, with the so-called Runge-Kutta Discontinuous Galerkin (RKDG) method, originally devised for numerically solving multi-dimensional hyperbolic systems of conservation laws, which is applied here to the convective part of the equations. Numerical simulations showing the performance of the new method are displayed, and the results compared with those obtained by using Essentially Nonoscillatory (ENO) finite difference schemes. Frommore »the perspective of device modeling, these methods are robust, since they are capable of encompassing broad parameter ranges, including those for which shock formation is possible. The simulations presented here are for Gallium Arsenide at room temperature, but we have tested them much more generally with considerable success.« less
Mukherjee, Souvik
2010-10-12
in both subsurface conductivity ? and relative permeability ?r. In this dissertation, I present a new three dimensional edge–based finite element (FE) algorithm capable of modeling the CSEM response of buried conductive and permeable targets. A coupled...
McArthur, Karl Edward
1996-01-01
The U.S. Geological Survey Surface Water Flow and Transport Model in Two-Dimensions (SV*9FT2D) model was applied to the northern half of the Laguna Madre Estuary. SW=D is a two dimensional hydrodynamic and transport model for well-mixed estuaries...
Efficient Computation of Info-Gap Robustness for Finite Element Models
Stull, Christopher J.; Hemez, Francois M.; Williams, Brian J.
2012-07-05
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
2009-04-08
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
2014-04-23
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).
A finite element model for transient thermal/structural analysis of large composite space structures
Lutz, James Delmar
1986-01-01
Composite Space Structures. (May 1986) James Delmar Lutz, B. S. , Texas A&M University Chairmen of Advisory Committee: Dr. David H. Allen Dr. Walter E. Haisler A finite element model is developed for predicting the transient thermal/structural response... of structures to be analyzed in order to simplify the heat load analysis. The first r estr iction applies to the geometry of struc- tures to be analyzed. An appropriate structure should be of open lattice-type construction and have highly repetitive...
Krabicka, J.; Yan, Y.
2009-08-15
Electrostatic sensors are used in certain industries for the flow measurement of pneumatically conveyed solids. However, despite various advances that have been made in recent years, relatively little information is known about the exact nature of the electrostatic charge induced onto the sensor electrode due to moving particles, which is dependent on electrode geometry, particle distribution, and particle velocity. This paper presents a novel approach to the study of the charge induced onto electrostatic sensors based on fitting a Lorentzian curve to the results of a finite-element model of the electrostatic sensor and pipeline. The modeling method is validated by comparing the modeling results of a nonintrusive circular electrode with an established analytical solution. The modeling results are used for in-depth analysis and informed design of a particular sensor configuration.
Cambridge, University of
Element Analysis, H. K. D. H. Bhadeshia Lecture 2: Finite Elements In finite element analysis, functions to be homogeneous. In finite element stress analysis, the elastic body is first divided into discrete connected. Thus, a finite element representation of a circle would be a circumscribed polygon, with each edge
DOLFIN: Automated Finite Element Computing
Logg, Anders; Wells, G N
2009-01-01
´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...
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
2003-12-06
a volume integral formulation of the problem with a finite partitioning set of ... where ?0 and ?1 partition the boundary of ?, the ds-measure of ?0 is strictly positive ...
Payan, Yohan
/lower lip contacts are also modeled. Simulations of smiling and of an Orbicularis Oris activationAbstract: A 3D biomechanical finite element model of the face is presented. Muscles are represented the mesh or the muscle implementation totally independently of each other. Lip/teeth and upper lip
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
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
Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.
Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay
2012-01-01
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.
Christian, Joshua M.; Ho, Clifford Kuofei
2010-04-01
Understanding the effects of gravity and wind loads on concentrating solar power (CSP) collectors is critical for performance calculations and developing more accurate alignment procedures and techniques. This paper presents a rigorous finite-element model of a parabolic trough collector that is used to determine the impact of gravity loads on bending and displacements of the mirror facets and support structure. The geometry of the LUZ LS-2 parabolic trough collector was modeled using SolidWorks, and gravity-induced loading and displacements were simulated in SolidWorks Simulation. The model of the trough collector was evaluated in two positions: the 90{sup o} position (mirrors facing upward) and the 0{sup o} position (mirrors facing horizontally). The slope errors of the mirror facet reflective surfaces were found by evaluating simulated angular displacements of node-connected segments along the mirror surface. The ideal (undeformed) shape of the mirror was compared to the shape of the deformed mirror after gravity loading. Also, slope errors were obtained by comparing the deformed shapes between the 90{sup o} and 0{sup o} positions. The slope errors resulting from comparison between the deformed vs. undeformed shape were as high as {approx}2 mrad, depending on the location of the mirror facet on the collector. The slope errors resulting from a change in orientation of the trough from the 90{sup o} position to the 0{sup o} position with gravity loading were as high as {approx}3 mrad, depending on the location of the facet.
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)
2012-01-15
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.
Firoozabadi, Abbas
approach to mitigate global warming. Several unique phase behavior properties make CO2 especially reservoirs, and the solubility in both light and heavy oil may be very high. [3] Upon dissolution, CO2 mayThree-phase compositional modeling of CO2 injection by higher-order finite element methods with CPA
Terzopoulos, Demetri
, PET and other noninvasive medical imaging technologies can provide exceptional views of internal elastically to t the image data. The tting process is mediated by internal forces stemming from the elastic tting process. Keywords: 3D/4D Medical Image Analysis, Deformable Models, Finite Elements, Dynamics
Yaman, Yavuz
VERIFICATION OF A FINITE ELEMENT MODEL OF AN UNMANNED AERIAL VEHICLE WING TORQUE BOX VIA Aeronautical Association, Faculty of Aeronautics and Astronautics, TURKEY KEYWORDS Unmanned Aerial Vehicle Wing (FEM) of an unmanned aerial vehicle wing torque box was verified by the experimental modal testing
James, Stephen M.
2011-08-08
? Matrix of eigenvectors of rotor [ ]rA ? Component mode synthesis transformation matrix for rotor [ ]XA ? Eigenvector matrix for X Z? plane [ ]YA ? Eigenvector matrix for Y Z? plane , , , b1 b2 b3 b4 ? Bearings used in component... [F] FEA ? Finite element analysis FEM ? Finite element methods ; 1:if i = m ? ith force matrix element in Guyan reduction [F] { }rBF ? Transformed rotor external forces matrix ; 1:rif i m= ? Force acting at the ith station of rotor...
MODELING OF HIGH SPEED FRICTION STIR SPOT WELDING USING A LAGRANGIAN FINITE ELEMENT APPROACH
Miles, Michael; Karki, U.; Woodward, C.; Hovanski, Yuri
2013-09-03
Friction stir spot welding (FSSW) has been shown to be capable of joining steels of very high strength, while also being very flexible in terms of controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding (RSW) if tool life is sufficiently high, and if machine spindle loads are sufficiently low so that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11-14 kN. Therefore, in the current work tool speeds of 3000 rpm and higher were employed, in order to generate heat more quickly and to reduce welding loads to acceptable levels. The FSSW process was modeled using a finite element approach with the Forge® software package. An updated Lagrangian scheme with explicit time integration was employed to model the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate [3]. The modeling approach can be described as two-dimensional, axisymmetric, but with an aspect of three dimensions in terms of thermal boundary conditions. Material flow was calculated from a velocity field which was two dimensional, but heat generated by friction was computed using a virtual rotational velocity component from the tool surface. An isotropic, viscoplastic Norton-Hoff law was used to model the evolution of material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures and the movement of the joint interface with reasonable accuracy for the welding of a dual phase 980 steel.
Massively Parallel Computing: Unstructured Finite Element Simulations
Johnsson, S. Lennart
of NAFEM 4th International Conference on Quality Assurance and Standards in Finite Element and Associated
Finite element modelling of shock-induced damages on ceramic hip prostheses
Uribe, Juliana; Geringer, Jean; 10.5402/2011/121486
2012-01-01
The aim of this work was to simulate the behaviour of hip prostheses under mechanical shocks. When hip joint is replaced by prosthesis, during the swing phase of the leg, a microseparation between the prosthetic head and the cup could occur. Two different sizes of femoral heads were studied: 28 and 32 mm diameter, made, respectively, in alumina and zirconia. The shock-induced stress was determined numerically using finite element analysis (FEA), Abaqus software. The influence of inclination, force, material, and microseparation was studied. In addition, an algorithm was developed from a probabilistic model, Todinov's approach, to predict lifetime of head and cup. Simulations showed maximum tensile stresses were reached on the cup's surfaces near to rim. The worst case was the cup-head mounted at 30^{\\circ}. All simulations and tests showed bulk zirconia had a greater resistance to shocks than bulk alumina. The probability of failure could be bigger than 0.9 when a porosity greater than 0.7% vol. is present in...
Collins, Gary S.
Discussion Data collected here will aid researchers in creating a more accurate crystal plasticity grant number DMR-1062898. Introduction Although various crystal plasticity finite element models (CPFEMs Â· Provide data for researchers to create crystal plasticity finite element models (CPFEM) that characterize
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
Programing the Finite Element Method with Matlab
2002-10-03
Oct 3, 2002 ... in the writing of finite element code using Matlab. It is assumed .... Ultimately for all finite element programs we solve a linear algebraic system of the form .... equations is the enforcement of the essential boundary conditions.
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE ...
2015-06-30
Scattering theory in periodic structures, which is crucial in application .... is used to design the adaptive finite element algorithm to choose elements for refine-.
Alternative Least-Squares Finite Element Models of Navier-Stokes Equations for Power-Law Fluids
Vallala, Venkat
2010-01-16
-Squares formulations of the original partial differential equations (PDE's) in terms of primary variables require C1 continuity of the finite element spaces across inter-element boundaries. This higherorder continuity requirement for PDE's in primary variables is a...
On simple and accurate finite element models for nonlinear bending analysis of beams and plates
Urthaler Lapeira, Yetzirah Yksya
2007-09-17
–ce of Graduate Studies of Texas A&M University in partial fulflllment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, J.N. Reddy Committee Members, Steve Suh Harry Hogan Goong Chen Head of Department, Dennis O’Neal May... Bolivar Chair of Advisory Committee: Dr. J.N. Reddy This study is concerned with the development of simple and accurate alterna- tive flnite element models to displacement flnite element models for geometrically nonlinear bending analysis of beams...
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
DOLFIN: Automated finite element computing
Logg, Anders; Wells, G N
2009-02-25
, and in particular the C++ Technical Report 1 (TR1) std::tr1::shared ptr and Boost boost:shared ptr (DOLFIN currently uses boost:shared ptr since this is better supported by SWIG than is std::tr1::shared ptr). In managing data sharing, this solution has reduced... . DOLFIN: Automated Finite Element Computing · 7 3. DESIGN CONSIDERATIONS The successful development of DOLFIN has been driven by two keys factors. The first is striving for technical innovation. Examples of this include the use of a form compiler...
Suresh, Krishnan
Submitted to: Finite Elements in Analysis and Design 1 Finite Element Analysis over Tangled element theory and commercial FEA packages are not designed to handle tangled meshes, i.e., they can lead element). Modern finite element theory and commercial FEA packages are not designed to handle tangled
De Castro, Carlos Armando
2011-01-01
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.
Peng, McKenna, Fenves, Law1 An Open Collaborative Model for Development of Finite Element Program
Stanford University
a reality. The open source software development process reflects a powerful global trend toward networked and engineers can easily incorporate new element technologies and solution strategies. The distributed element engineering analysis programs. In current engineering practice, finite element packages need to be able
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
Pontaza, Juan Pablo
2004-09-30
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 ...
k - Version of Finite Element Method for Polymer flows using Giesekus Constitutive Model
Deshpande, Kedar M.
2008-01-31
= Velocity in x direction v = Dimensionless Velocity in x direction ??xx = Normal Stress in x direction ?xx = Dimensionless Normal Stress in x direction ??yy = Normal Stress in y direction ?yy = Dimensionless Normal Stress in y direction ??xy = Shear Stress... of Pressure p over an element primeeprime ?hxx = Interpolation of normal stress ?xx over an element primeeprime ?hyy = Interpolation of normal stress ?yy over an element primeeprime ?hxy = Interpolation of shear stress ?xy over an element primeeprime ??p...
Validation of Finite-Element Models of Persistent-Current Effects in Nb3Sn Accelerator Magnets
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, X.; Ambrosio, G.; Chlachidze, G.; Collings, E. W.; Dietderich, D. R.; DiMarco, J.; Felice, H.; Ghosh, A. K.; Godeke, A.; Gourlay, S. A.; et al
2015-01-06
Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality degradation, in particular at low field where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb3Sn accelerator magnets. Here a finite-element method based on the measured strand magnetization is validated against three state-of-art Nb3Sn accelerator magnets featuring different subelement diameters, critical currents, magnet designsmore »and measurement temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent current effects is discussed. The performance, limitations and possible improvements of the approach are also discussed.« less
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
Liu, Mian
How does trench coupling lead to mountain building in the Subandes? A viscoelastoplastic finite cause of the Andean mountain building. The present-day crustal shortening in the Andes is clear from the cyclic trench coupling leads to long-term mountain building, which has been concentrated in the Subandes
Yu, Guangbin [The Higher Educational Key Laboratory for Measuring and Control Technology and Instrumentations of Heilongjiang Province, Harbin University of Science and Technology, Harbin 150080 (China); Tang, Chaolong [Department of Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), University of Alabama, Tuscaloosa, Alabama 35487 (United States); Song, Jinhui, E-mail: jhsong@eng.ua.edu, E-mail: wqlu@cigit.ac.cn [The Higher Educational Key Laboratory for Measuring and Control Technology and Instrumentations of Heilongjiang Province, Harbin University of Science and Technology, Harbin 150080 (China); Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China); Department of Metallurgical and Materials Engineering, Center for Materials for Information Technology (MINT), University of Alabama, Tuscaloosa, Alabama 35487 (United States); Lu, Wenqiang, E-mail: jhsong@eng.ua.edu, E-mail: wqlu@cigit.ac.cn [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714 (China)
2014-04-14
Based on conductivity characterization of single crystal zinc oxide (ZnO) micro/nanobelt (MB/NB), we further investigate the physical mechanism of nonlinear intrinsic resistance-length characteristic using finite element method. By taking the same parameters used in experiment, a model of nonlinear anisotropic resistance change with single crystal MB/NB has been deduced, which matched the experiment characterization well. The nonlinear resistance-length comes from the different electron moving speed in various crystal planes. As the direct outcome, crystallography of the anisotropic semiconducting MB/NB has been identified, which could serve as a simple but effective method to identify crystal growth direction of single crystal semiconducting or conductive nanomaterial.
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors
Jüngel, Ansgar
Analisi Numerica, C.N.R., Via Ferrata 1, 27100 Pavia, Italy, e-mail: pietra@dragon.ian.pv.cnr.it. Abstract-transport equations in two space dimensions. More precisely, we adopt the #12;nite-element scheme, proposed by Marini
Finite element analysis of multilayer coextrusion.
Hopkins, Matthew Morgan; Schunk, Peter Randall; Baer, Thomas A.; Mrozek, Randy A.; Lenhart, Joseph Ludlow; Rao, Rekha Ranjana; Collins, Robert; Mondy, Lisa Ann
2011-09-01
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
Generalized finite element method for Helmholtz equation
Hidajat, Realino Lulie
2009-05-15
This dissertation presents the Generalized Finite Element Method (GFEM) for the scalar Helmholtz equation, which describes the time harmonic acoustic wave propagation problem. We introduce several handbook functions for ...
PARTIALLY PENALIZED IMMERSED FINITE ELEMENT METHODS ...
2015-01-05
This article presents new immersed finite element (IFE) methods for solving the ... convergence rate in an energy norm provided that the exact solution has ... An alternative approach is ...... North-Holland Publishing Co., Amsterdam-New York-.
Finite Element Analysis of the Schroedinger Equation
Avtar S. Sehra
2007-04-17
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.
King, Joshua David
2005-02-17
are produced as a result of interaction of the transmitter generated primary fields with the seawater and subsurface. Badea et al. (2001) coded an existing algorithm for solving Maxwell?s equations. This finite element 3D forward modeling algorithm is used...
RodrÃguez, Rodolfo
Â´on, Chile. This paper deals with the approximation of the bending of a clamped plate modeled by ReissnerNumerical analysis of a locking-free mixed finite element method for a bending moment formulation the thickness t is small. Here, we propose a new mixed formulation in terms of the bending moments, shear stress
Pettit, J. R. [Rolls-Royce Nuclear, PO BOX 2000, Derby, UK, DE21 7XX and Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Walker, A. [Rolls-Royce Nuclear, PO BOX 2000, Derby DE21 7XX (United Kingdom); Lowe, M. J. S. [Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2014-02-18
Defects which posses rough surfaces greatly affect ultrasonic wave scattering behaviour, often reducing the magnitude of reflected signals. Ultrasonic inspections rely upon this response for detecting and sizing flaws. For safety critical components reliable characterisation is crucial. Therefore, providing an accurate means to predict reductions in signal amplitude is essential. An extension of Kirchhoff theory has formed the basis for the UK power industry inspection justifications. However, it is widely recognised that these predictions are pessimistic owing to analytical approximations. A numerical full field modelling approach does not fall victim to such limitations. Here, a Finite Element model is used to aid in setting a non-conservative reporting threshold during the inspection of a large pressure vessel forging that might contain embedded rough defects. The ultrasonic response from multiple rough surfaces defined by the same statistical class is calculated for normal incident compression waves. The approach is validated by comparing coherent scattering with predictions made by Kirchhoff theory. At lower levels of roughness excellent agreement is observed, whilst higher values confirm the pessimism of Kirchhoff theory. Furthermore, the mean amplitude in the specular direction is calculated. This represents the information obtained during an inspection, indicating that reductions due to increasing roughness are significantly less than the coherent component currently being used.
Mongkolcheep, Kathira
2010-10-12
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 multi-scale iterative approach for finite element modeling of thermal contact resistance
Thompson, Mary Kathryn, 1980-
2007-01-01
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 ...
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method
Wang, G.; Liu, M.
2005-01-01
A method, based on simulation models, for active functional tests and optimization of coil energy recovery loop systems in Air Handling Units (AHUs) have been developed and a first version implemented in the program Engineering Equation Solver (EES...
Ionic Polymer-Metal Composites: Thermodynamical Modeling and Finite Element Solution
Arumugam, Jayavel
2012-10-19
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...
FINITE ELEMENT MODELS OF THE TONGUE AND VELUM FOR A PHYSICAL UNDERSTANDING OF SLEEP APNEA SYNDROME
Payan, Yohan
midsagittal radiography of a patient. The tongue model integrates the main extrinsic and intrinsic muscles that are responsible for tongue deformations and displacements inside the mouth (genioglossus, hyoglossus, styloglossus, verticalis, longitudinalis) The lingual and velar deformations induced by muscle activations and by airflow
Computers & Geosciences 31 (2005) 297307 Finite-element modelling of contemporary and palaeo-
Müller, Dietmar
2005-01-01
.albert@exxonmobil.com (R.A. Albert), dietmar@geosci.usyd.edu.au (R.D. Mu¨ ller). 1 Present address: ExxonMobil Upstream data and reactivation histories over the NW Shelf and Bass Strait regions of the Australian continent SHmax data can be sparse over large areas of continents and over geologic time, geophysical model- ling
Finite element modeling of long-term fluid-structure interaction problems in geological media
Anderson, C.A.
1980-01-01
A model is developed to predict long-term thermal creep and creep rupture in geological structures under multiaxial stress states and under elevated temperature conditions. An example of the method is given showing the behavior of the crust and mantle while undergoing intrusion by a low density diaper. (ACR)
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
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
FULLYDISCRETE FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY
Ewing, Richard E.
FULLYDISCRETE FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY Zhangxin Chen element method for a nonlinear differential system for describing an airwater system in groundwater experiments using the present approach for modeling groundwater flow in porous media are reported. Key words
Raut, Ameeta A.
2010-07-14
fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, J. N. Reddy Committee Members, Ibrahim Karaman Jose Roesset Head of Department, Dennis O?Neal December 2009 Major Subject: Mechanical... of Advisory Committee: Dr. J. N. Reddy The conventional finite element models (FEM) of problems in structural mechanics are based on the principles of virtual work and the total potential energy. In these models, the secondary variables...
ECI 212A: Finite Element Procedures in Applied Mechanics
Schladow, S. Geoffrey
), "The Finite Element Method: Linear Static and Dynamic Finite Element Analysis," Prentice), "Concepts and Appli- cations of Finite Element Analysis," 4th Ed., John Wiley and Sons, NY. 5. M. S, Philadelphia, PA. 6. G. Strang and G. J. Fix (1973), "An Analysis of the Finite Element Method," Prentice
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
2005-01-01
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
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
Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING
Dennis, Brian
1 Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING OF REALISTIC 3-D Rapid cooling of the brain in the first minutes following the onset of cerebral ischemia is a potentially attractive preservation method. This computer modeling study was undertaken to examine brain-cooling
Discontinuous finite element methods for particle transport problems
Stone, Hiromi
2002-01-01
We develop, analyze, and test a new discontinuous finite element method (DFEM), namely the piece-wise linear discontinuous (PWLD) method for transport problems. We compare the PWLD method against the rational finite element (RFE) method. We show...
B-spline finite elements for plane elasticity problems
Aggarwal, Bhavya
2007-04-25
The finite element method since its development in the 1950Ã¢Â?Â?s has been used extensively in solving complex problems involving partial differential equations. The conventional finite element methods use piecewise ...
Course Announcement: Spring 2015 Finite Element Methods for Engineers
.v.griffiths@mines.edu Web: www.mines.edu/~vgriffit This course combines finite element theory with practical programming
The Uranium Processing Facility (UPF) Finite Element Meshing Discussion
Broader source: Energy.gov [DOE]
The Uranium Processing Facility (UPF) Finite Element Meshing Discussion Loring Wyllie Arne Halterman Degenkolb Engineers, San Francisco
Beaumont, Christopher
1 Salt tectonics driven by differential sediment loading: Stability analysis and finite element of the basin. We use 2-D finite element modelling to investigate systems in which a linear viscous salt layer is used to investigate the subsequent finite deformation. As the systems evolve, overburden extension
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
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
2015-01-01
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...
SYMMETRIC NON-CONFORMING MIXED FINITE ELEMENTS FOR LINEAR ELASTICITY
GuzmÃ¡n, Johnny
. However, stress elements are difficult to design due to two requirements. First, due to conservation finite elements satisfying both these requirements have been designed in [1, 8, 4, 3]. But the mainSYMMETRIC NON-CONFORMING MIXED FINITE ELEMENTS FOR LINEAR ELASTICITY J. GOPALAKRISHNAN AND J. GUZM
Morris, J; Johnson, S
2007-12-03
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.
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
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 ...
The Uranium Processing Facility Finite Element Meshing Discussion
Office of Environmental Management (EM)
Uranium Processing Facility (UPF) Finite Element Meshing Discussion ...Need picture of Building... October 25, 2011 Department of Energy - Natural Phenomenon Hazard Workshop 1...
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
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
2013-10-31
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-
2014-01-01
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 ...
3-D Finite Element Analyses of the Egan Cavern Field
Klamerus, E.W.; Ehgartner, B.L.
1999-02-01
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.
SEACAS Theory Manuals: Part III. Finite Element Analysis in Nonlinear Solid Mechanics
Laursen, T.A.; Attaway, S.W.; Zadoks, R.I.
1999-03-01
This report outlines the application of finite element methodology to large deformation solid mechanics problems, detailing also some of the key technological issues that effective finite element formulations must address. The presentation is organized into three major portions: first, a discussion of finite element discretization from the global point of view, emphasizing the relationship between a virtual work principle and the associated fully discrete system, second, a discussion of finite element technology, emphasizing the important theoretical and practical features associated with an individual finite element; and third, detailed description of specific elements that enjoy widespread use, providing some examples of the theoretical ideas already described. Descriptions of problem formulation in nonlinear solid mechanics, nonlinear continuum mechanics, and constitutive modeling are given in three companion reports.
Adaptive Finite Elements and Colliding Black Holes
Douglas N. Arnold; Arup Mukherjee; Luc Pouly
1997-09-15
According to the theory of general relativity, the relative acceleration of masses generates gravitational radiation. Although gravitational radiation has not yet been detected, it is believed that extremely violent cosmic events, such as the collision of black holes, should generate gravity waves of sufficient amplitude to detect on earth. The massive Laser Interferometer Gravitational-wave Observatory, or LIGO, is now being constructed to detect gravity waves. Consequently there is great interest in the computer simulation of black hole collisions and similar events, based on the numerical solution of the Einstein field equations. In this note we introduce the scientific, mathematical, and computational problems and discuss the development of a computer code to solve the initial data problem for colliding black holes, a nonlinear elliptic boundary value problem posed in an unbounded three dimensional domain which is a key step in solving the full field equations. The code is based on finite elements, adaptive meshes, and a multigrid solution process. Here we will particularly emphasize the mathematical and algorithmic issues arising in the generation of adaptive tetrahedral meshes.
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
Plane-wave fluorescence tomography with adaptive finite elements
Bangerth, Wolfgang
Plane-wave fluorescence tomography with adaptive finite elements Amit Joshi Photon Migration reflectance imaging setup. The method employs planar illumination with modulated light and frequency domain fluo- rescence measurements made on the illumination plane. An adaptive finite-element algorithm
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
Rodríguez, Rodolfo
of an induction furnace ALFREDO BERM ´UDEZ Departamento de Matem´atica Aplicada, Universidade de Santiago de problem arising from the modeling of an induction furnace. By taking advantage of the cylindrical symmetry a formulation of the eddy current problem arising from the modeling of an induction furnace, which is based
Liu, Xuchen
2015-05-04
surrounded by soft tissues, 2) a layered ring model representing an arterial wall cross-section. The hypothetical "measured" displacement field for these problem domains will be created by solving the finite element forward problem. Additionally, noise...
Finite element analysis of elastic interaction of two en echelon overlapping faults
Leem, Junghun
1995-01-01
on the faults. Attention is focuses on the role of variable fault spacing and overlap for constant far-field compressive principal stresses. The linear elastic, isotropic, plane strain, finite element analyses are obtained. The basic modeling approach...
Barkan, Christopher P.L.
as well as the development of high-speed passenger rail in North America. In light of these ever) model of prestressed concrete sleepers and fastening systems for US high speed rail and joint passenger to the development of high speed rail corridors and increasing axle loads. Currently, there is little understanding
Santos, Juan
Aligned fractures modeled as boundary conditions within saturated porous media and induced´e M. Carcione, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, OGS SUMMARY Fractures in a fluid-saturated poroelastic -Biot- medium are very thin, compliant and highly permeable layers. Fracture
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
2004-01-01
to an increase in the ambien perature above the system design point, a rigi rt-tube can sometimes provide a high enough flow e to flood the compressor with saturated refrigerant the other hand, when the condenser pressur . 1. Schematic of the flexible short...Pa were studied. Four upstream and downstream pressures were applied and the upstream subcooling was held at a constant value of 16.7 ?C. Mass flow rates from the numerical model were compared to available published experimental results. The study showed...
Finite-volume matrix elements in multiboson states
Detmold, William
We derive the relations necessary for the extraction of matrix elements of multihadron systems from finite-volume lattice QCD calculations. We focus on systems of n ? 2 weakly interacting identical particles without spin. ...
Benchmarking of finite element codes for radioactive material transportation packages
Ammerman, D.J.
1996-10-01
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.
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
An application of stochastic finite element method in structural reliabiity
Agrawal, Sanjay
1993-01-01
AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SAN JAY AGRAWAL Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1993 Major Subject: Civil Engineering AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SANJAY AGRAWAL Approved as to style and content by: Kostas apadimitriou (Chair of Committee) John M...
JOURNAL OF MATERIALS SCIENCE 38 (2003) 307 322 Crystal plasticity-based finite element analysis
Grujicic, Mica
2003-01-01
JOURNAL OF MATERIALS SCIENCE 38 (2003) 307 322 Crystal plasticity-based finite element analysis-dependent, finite-strain, crystal-plasticity based materials constitutive model is used to represent the deformation obtained show that plastic flow localizes into deformation bands even at an overall strain level of only 0
A LOCAL PROJECTION STABILIZATION FINITE ELEMENT METHOD WITH NONLINEAR CROSSWIND DIFFUSION FOR
John, Volker
A LOCAL PROJECTION STABILIZATION FINITE ELEMENT METHOD WITH NONLINEAR CROSSWIND DIFFUSION and phrases. finite element method; local projection stabilization; crosswind diffusion; convection
R.W. Carpick; M.E. Plesha
2007-03-03
This report describes the accomplishments of the DOE BES grant entitled "Development and Integration of Single-Asperity Nanotribology Experiments & Nanoscale Interface Finite Element Modeling for Prediction and Control of Friction and Damage in Micro- and Nano-mechnical Systems". Key results are: the determination of nanoscale frictional properties of MEMS surfaces, self-assembled monolayers, and novel carbon-based films, as well as the development of models to describe this behavior.
Evaluation of an existing bridge`s modal properties using simplified finite element analysis
Farrar, C.R.; Duffey, T.A.
1996-02-01
The purpose of this paper is to present results of a simplified approach to the dynamic finite element modeling of composite girder-slab bridges using a single beam element to represent the girder-slab cross section. Dynamic properties calculated with these simplified models are compared to experimental results and results obtained from more detailed shell element models. The method for modeling flexural behavior is first discussed followed by a discussion of modeling torsional behavior. The beam element models accurately calculated the mode shapes of the structure, but the associated resonant frequencies showed some error.
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE WAVE ...
2015-09-09
Consider the acoustic wave scattering by an impenetrable obstacle in two dimensions. ... adaptive finite element algorithm is proposed for solving the acoustic ... element methods [19,20] and the boundary integral equation methods [11]. ...... rem 4.1, we use the PDE toolbox of MATLAB to implement the adaptive algorithm of.
Experimental and finite element analysis of high pressure packer elements
Berger, Stephanie, 1981-
2004-01-01
Packer elements are traditionally rubber seals that can operate under specified downhole conditions and provide a seal for either a short-term, retrievable, or a long-term, permanent, completion. In this case a retrievable ...
Direct Forcing Immersed Boundary Methods: Finite Element Versus Finite Volume Approach
Frisani, Angelo 1980-
2012-12-07
immersed boundary methods are in good agreement with the predictions from STAR-CCM+ and the numerical data from the other IBMs. The immersed boundary method based of finite element approach is numerically more accurate than the IBM based on finite volume...
Formulation and analysis of a three-dimensional finite element implementation for adhesive contact-dimensional finite element model for nanoscale contact problems with strong adhesion is presented. The contact the BF formulation but loses accuracy as the strength of adhesion increases. The model has applications
Finite element analyses of a linear-accelerator electron gun
Iqbal, M. E-mail: muniqbal@ihep.ac.cn; Wasy, A.; Islam, G. U.; Zhou, Z.
2014-02-15
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.
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
Hierarchical strategy for rapid finite element analysis
Varghese, Julian
2004-09-30
advantage. The proposed system's forte is its hierarchical framework that allows models to communicate with each other and share information with one another. This makes it ideal for global local analyses where solutions from a global model are used...
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01
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.
Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint
Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.
2014-01-01
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.
Paris-Sud XI, Université de
2002-01-01
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
ANALYSIS AND FINITE ELEMENT APPROXIMATION OF A
Fairag, Faisal
IN STREAMFUNCTION FORM 1 Faisal A. Fairag Department of Mathematical Sciences, King Fahd University of Petroleum incom- pressible flow. An excellent piece of motivation why one consider this model Email address
ANALYSIS AND FINITE ELEMENT APPROXIMATION OF A
Fairag, Faisal
IN STREAMFUNCTION FORM 1 Faisal A. Fairag Department of Mathematical Sciences, King Fahd University of Petroleum incom pressible flow. An excellent piece of motivation why one consider this model Email address
Electrogalvanic finite element analysis of partially protected marine structures
Kasper, R.G.; April, M.G.
1983-05-01
A general finite element modeling (FEM) procedure for calculating electrogalvanic field responses due to multiple anodic/cathodic interactions has been developed. Within any defined electrolytic continuum the exact geometry and location of anodes, cathodes, and paint surfaces can now be realistically incorporated in the mathematical model formulation. The anodic/cathodic interactions in the conductive electrolyte are predicted by the application of classical d.c. electric field theory for conductive continuums in conjunction with widely accepted laboratory oxidation/reduction responses for the electrodes. The electrogalvanic fields in the electrolyte are calculated using the scalar Poisson equation whereby traditional boundary conditions are prescribed in the far field of the electrolyte. In the near field of the anodes, cathodes, and the painted metallic substrate, complex boundary conditions are enforced based on empirical polarization curves and paint impedance values. The ionic current in the electrolyte leaving the anode and arriving at the cathodes are mathematically constrained to sum to zero over the metallic surface (spatial Kirchoff's law). Three example problems (three dimensional) of an iron bar in salt water will demonstrate the electrochemical field effects due to relative anodic/cathodic spacing, anodic/cathodic geometries, and infinite paint impedance. A fourth boundary value problem (two dimensional) will illustrate the effect of a paint discontinuity (unprotected area) in the center of the otherwise painted (finite impedance) metallic substrate. The proposed electrochemical modeling procedure has the advantage of concurrently treating numerous essential electrochemical parameters for any geometric anodic/cathodic configurations consistent with the physical laws of electrochemistry.
High Order Finite Element Solution of Elastohydrodynamic Lubrication Problems
Jimack, Peter
High Order Finite Element Solution of Elastohydrodynamic Lubrication Problems by Hongqiang Lu-dimensional Elastohydro- dynamic Lubrication (EHL) problems (line contact and point contact). This thesis pro- vides an introduction to elastohydrodynamic lubrication, including some history, and a description of the underlying
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
brachytherapy seeds are presented. 1 Introduction This paper considers finite element techniques for non-rigidly registering three- dimensional prostate images acquired for the purpose of brachytherapy plan- ning and guidance. Brachytherapy involves implanting radioactive seeds in the prostate to treat prostate cancer
STRUCTURAL TOPOLOGY OPTIMIZATION USING FINITE ELEMENT BASED LEVEL SET METHOD
Frey, Pascal
of Mechanical and Automation Engineering The Chinese University of Hong Kong THEME Optimization KEYWORDS, the standard Galerkin finite element method may produce oscillating results. In this paper, both equations set equation is a first order hyperbolic equation. It is well known that the standard Galerkin FEM may
Lim, Jong Il
2007-04-25
Finite element analysis of electric double layer capacitors using a transient nonlinear Nernst-Planck-Poisson (NPP) model and Nernst-Planck-Poisson-modified Stern layer (NPPMS) model are presented in 1D and 2D. The NPP ...
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
Bangerth, Wolfgang
error estimates for adaptive mesh refinement to optimally model the strongly graded light distributionADAPTIVE FINITE ELEMENT METHODS FOR FLUORESCENCE ENHANCED FREQUENCY DOMAIN OPTICAL TOMOGRAPHY Modeling, ICES, University of Texas at Austin, TX ABSTRACT In this contribution we introduce adaptive
An Annotated Reference Guide to the Finite-Element Interface Specification Version 1.0
Alan B. Williams; Ivan J. Otero; Kyran D. Mish; Lee M. Tayor; Robert L. Clay
1999-04-01
The Finite-Element Interface (FEI) specification provides a layered abstraction that permits finite-element analysis codes to utilize various linear-algebra solution packages with minimal concern for the internal details of the solver modules. Alternatively, this interface can be viewed as a way for solver developers to provide solution services to finite-element clients without having to embed finite-element abstractions within their solver libraries. The purpose of this document is to provide some level of documentation between the bare interface specification itself, which consists only of C/C++ header files, and the full documentation suite that supports the interface definition by providing considerable detail as to its design and implementation. This document primarily provides the ''how'' of calling the interface member functions, so that programmers can readily learn how to utilize the interface implementation without having to consider all the details contained in the interface's definition, design, and motivation. The interface specification is presented three times in this document, each time with an increasing level of detail. The first presentation provides a general overview of the calling sequence, in order to acquaint the programmer with a basic introduction to how the interface is used to ''train'' the underlying solver software on the particular finite-element problem that is to be solved. The second pass through the interface definition provides considerable detail on each method, including specific considerations as to the structure of the underlying data, and an exposition of potential pitfalls that may occur as a byproduct of either the finite-element modeling process, or of the use of the associated interface implementation. Finally, a third description of the interface is given implicitly via the discussion of sample problems that provide concrete examples of the use of the finite-element interface.
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
2011-10-10
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.
Finite size scaling for quantum criticality using the finite-element method
Edwin Antillon; Birgit Wehefritz-Kaufmann; Sabre Kais
2012-03-08
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.
Finite Elements in Analysis and Design 43 (2007) 397410 www.elsevier.com/locate/finel
Ghosh, Somnath
2007-01-01
Finite Elements in Analysis and Design 43 (2007) 397410 www.elsevier.com/locate/finel Modeling. Li, S. Ghosh Department of Mechanical Engineering, The Ohio State University, Columbus, OH, USA of damages is a challenging topic due to various kinematic and morphological complexities. Conventional
Jimack, Peter
On the linear finite element analysis of fully-coupled point contact elastohydrodynamic lubrication lubrication (EHL) point contact problems requires the numerical solution of the elasticity prob- lem, technique is applied. KEYWORDS: elastohydrodynamic lubrication; finite element method; linear elasticity
Jimack, Peter
An adaptive finite element procedure for fully-coupled point contact elastohydrodynamic lubrication to control adaptivity in both the elasticity and the lubrication domains. The implementation is based levels grows. KEYWORDS: elastohydrodynamic lubrication; finite element method; linear elasticity; fully
Implementation of finite element analysis into the athletic shoe design process
Hidalgo, Maria E. (Maria Estela), 1982-
2004-01-01
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 ...
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 ...
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 ...
Implementation of B-splines in a Conventional Finite Element Framework
Owens, Brian C.
2010-01-16
that describe the process of implementing B-splines into an existing finite element framework. Therefore, it is necessary to document this methodology. This implementation should conform to the structure of conventional finite elements and only require...
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
Finite Elements in Analysis and Design 42 (2006) 580591 www.elsevier.com/locate/finel
Li, Shaofan
2006-01-01
Finite Elements in Analysis and Design 42 (2006) 580591 www.elsevier.com/locate/finel A variational multiscale stabilized finite element method for the Stokes flow problem Xiaohu Liu , Shaofan Li order Finite Element intepolation pairs and has a formulation similar to the one of Galerkin
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
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
ANL/APS/TB-19 A Finite Element Analysis of Room Temperature Silicon Crystals
Kemner, Ken
ANL/APS/TB-19 A Finite Element Analysis of Room Temperature Silicon Crystals for the Advanced #12;ANL/APS/TB-19 1 A Finite Element Analysis of Room Temperature Silicon Crystals for the Advanced if the monochromator is not properly designed (or cooled). This document describes a series of finite element analyses
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
2004-01-01
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
ME 538: Introduction to Finite Element Methods and Analysis Instructor and Class Information
Lin, Xi
ME 538: Introduction to Finite Element Methods and Analysis Fall 2014 Instructor and Class edition, Thomson 2012 Reference Books · Concepts and applications of finite element analysis by R.D. Cook@gmail.com) Course Summary This class serves as an introduction to the linear finite element method, and its
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
Gao, Kai; Gibson, Richard L; Chung, Eric T; Efendiev, Yalchin
2014-01-01
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both boundaries and the interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale medium property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and di...
An efficient finite element method applied to quantum billiard systems
Woo-Sik Son; Sunghwan Rim; Chil-Min Kim
2009-02-25
An efficient finite element method (FEM) for calculating eigenvalues and eigenfunctions of quantum billiard systems is presented. We consider the FEM based on triangular $C_1$ continuity quartic interpolation. Various shapes of quantum billiards including an integrable unit circle are treated. The numerical results show that the applied method provides accurate set of eigenvalues exceeding a thousand levels for any shape of quantum billiards on a personal computer. Comparison with the results from the FEM based on well-known $C_0$ continuity quadratic interpolation proves the efficiency of the method.
Guaranteed Verification of Finite Element Solutions of Heat Conduction
Wang, Delin
2012-07-16
||uSp?h ||C, and the relative value of C-norm of the error ||eh||C / ||u||C, for the semi-discrete solutions of degree p = 1, 2 and 3, computed using uniform meshes with mesh size h = L2n , n = 1, 2, 3, and 4 respectively.... . . . . . . . . . . . . . . . . . 67 4.2 Heat transition problem in one dimension. The effectivity indices ? based on the exact solution u? and ?Sp+k?h? = ESp+k?h? /||eh||C based on the finite element solution u?Sp+k?h? (k = 1, 2, 3, and ?h? from the nest subdivision...
Conditioning of finite element equations with arbitrary anisotropic meshes
Kamenski, Lennard; Huang, Weizhang; Xu, Hongguo
2014-03-05
OF COMPUTATION Volume 83, Number 289, September 2014, Pages 2187–2211 S 0025-5718(2014)02822-6 Article electronically published on March 5, 2014 CONDITIONING OF FINITE ELEMENT EQUATIONS WITH ARBITRARY ANISOTROPIC MESHES LENNARD KAMENSKI, WEIZHANG HUANG... scaling. This work was supported in part by the DFG (Germany) under grants KA 3215/1-1 and KA 3215/2-1 and the National Science Foundation (U.S.A.) under grants DMS-0712935 and DMS- 1115118. c©2014 American Mathematical Society Reverts to public domain 28...
Taflove, Allen
, and bone tissue on simulated surface electromyographic (EMG) signals was examined using a finite of the surface electromyographic (EMG) signal has proved to be a valuable tool in helping to interpret
An Augmented Lagrangian Mixed Finite Element Scheme for Saddle Point Problems \\Lambda
Yang, Daoqi
on the idea of iteratively penalizing the mixed finite element scheme. It is shown that the scheme has \\Delta /dx: Its mixed finite element approximations consist of constructing finite dimensional spaces [5 ); (9) where \\Pi is the L 2 projection operator onto Q. The convergence for this method is ku \\Gamma um
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
FINITE ELEMENT ANALYSIS OF BULK TRITIUM SHIPPING PACKAGE
Jordan, J.
2010-06-02
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.
ANALYSIS OF MIXED FINITE ELEMENTS FOR LAMINATED COMPOSITE PLATES
Lovadina, Carlo
an extension-bending coupling (i.e. in-plane displacements arise even for vertical loads). The paper- dard membrane element for the in-plane displacements with a robust method for plate bending problem direction; Â· they exhibit extension-bending coupling. In literature, many different models have been
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)
2014-02-18
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.
Rumpf, Martin
16th Workshop on the Finite Element Method in Biomedical Engineering, Biomechanics and Related. This is a convenient approach in practice because frequently in biomechanics geometric interfaces are described via 3D
An h-adaptive finite element method for turbulent heat transfer
Carriington, David B [Los Alamos National Laboratory
2009-01-01
A two-equation turbulence closure model (k-{omega}) using an h-adaptive grid technique and finite element method (FEM) has been developed to simulate low Mach flow and heat transfer. These flows are applicable to many flows in engineering and environmental sciences. Of particular interest in the engineering modeling areas are: combustion, solidification, and heat exchanger design. Flows for indoor air quality modeling and atmospheric pollution transport are typical types of environmental flows modeled with this method. The numerical method is based on a hybrid finite element model using an equal-order projection process. The model includes thermal and species transport, localized mesh refinement (h-adaptive) and Petrov-Galerkin weighting for the stabilizing the advection. This work develops the continuum model of a two-equation turbulence closure method. The fractional step solution method is stated along with the h-adaptive grid method (Carrington and Pepper, 2002). Solutions are presented for 2d flow over a backward-facing step.
A PIECEWISE LINEAR FINITE ELEMENT METHOD FOR THE BUCKLING AND THE VIBRATION PROBLEMS OF THIN
Rodríguez, Rodolfo
A PIECEWISE LINEAR FINITE ELEMENT METHOD FOR THE BUCKLING AND THE VIBRATION PROBLEMS OF THIN PLATES finite element method to approximate the buckling and the vibration problems of a thin plate. The method]). The method was applied to the plate vibration problem in [6] and [17, Section 7(b)], where it was proved
Finite Elements in Analysis and Design 40 (2004) 16191640 www.elsevier.com/locate/nel
Ghosh, Somnath
2004-01-01
Finite Elements in Analysis and Design 40 (2004) 16191640 www.elsevier.com/locate/ÿnel Two scale. Raghavan et al. / Finite Elements in Analysis and Design 40 (2004) 16191640 performed by the method-scale analysis of composite structures with non-uniform microstructural heterogeneities as obtained from optical
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
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS
RodrÃguez, Rodolfo
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS FELIPE LEPE, DAVID MORA, AND RODOLFO RODRÂ´IGUEZ Abstract. In this paper we study a finite element formulation of the transverse displacement, rota- tion, shear stress and bending moment. By using the classical Babuska
TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities
TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities F. Marhauser BESSY GmbH #12;TESLA FEL Report 200602 Contents 1. INTRODUCTION......................................................................................................................................................28 #12;TESLA FEL Report 200602 Finite Element Analyses for RF Photoinjector Gun Cavities F
STATISTICAL AND 3D NONLINEAR FINITE ELEMENT ANALYSIS OF SCHLEGEIS DAM
Balaji, Rajagopalan
STATISTICAL AND 3D NONLINEAR FINITE ELEMENT ANALYSIS OF SCHLEGEIS DAM VICTOR SAOUMA, ERIC HANSEN is composed of two parts. First a statistical analysis of the dam crest displacement is performed, along with a prediction for the years 2000-2001. Then a 3D finite element analysis of Schlegeis dam is performed using
Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls
Bruneau, Michel
Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls.k.a. perforated SPSW . Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips with variation in perforation diameter, to develop a fundamental understanding
FINITE ELEMENT INVESTIGATION AND DESIGN RECOMMENDATIONS FOR PERFORATED STEEL PLATE SHEAR WALLS
Bruneau, Michel
FINITE ELEMENT INVESTIGATION AND DESIGN RECOMMENDATIONS FOR PERFORATED STEEL PLATE SHEAR WALLS of the behavior of unstiffened thin SPSW having a regular pattern of openings (a.k.a. perforated SPSW). Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips
Christian Kreuzer; Endre Süli
2015-03-18
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].
Finite element simulation of magnetic detection of creep damage at seam welds
Sablik, M.J.; Rubin, S.W.; Jiles, D.C.; Kaminski, D.; Bi, Y.
1996-09-01
Using appropriately modified magnetization curves for each element of creep-damaged material, a finite element calculation has been carried out to simulate magnetic detection of non-uniform creep damage around a seam weld in a 2.25 Cr 1 Mo steam pipe. The magnetization curves for the creep-damaged elements were obtained from an earlier model for the magnetic effect of a uniformly creep-damaged material as given by Chen, et al. In the finite element calculation, a magnetic C-core with primary and secondary coils was placed with its pole pieces flush against the specimen in the vicinity of the weld. The secondary emf was shown to be reduced when creep damage was present inside the pipe wall at the cusp of weld and in the vicinity of the cusp. The C-core detected the creep damage best if it completely spanned the weld seam width. Also, the current in the primary needed to be such that the C-core was not magnetically saturated.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-04-14
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale mediummore »property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.« less
Volk, Brent Louis 1985-
2012-10-16
of applied strain. Using the uniaxial experimental data, the model is then calibrated and compared to the 1-D experimental results. The validated finite element analysis tool is then used to model biomedical devices, including cardiovascular tubes...
Finite Models for Arithmetical Quantum Chaos
Terras, Audrey
Finite Models for Arithmetical Quantum Chaos Audrey Terras Math. Dept., U.C.S.D., San Diego, Ca termed by Sarnak "arithmetic quantum chaos" when the manifolds are quotients of a symmet- ric space have been evident to physicists for some time. Here we survey what may be called "finite quantum chaos
Finite element analyses for seismic shear wall international standard problem
Park, Y.J.; Hofmayer, C.H.
1998-04-01
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.
hp-finite-elements for simulating electromagnetic fields in optical devices with rough textures
Burger, S; Hammerschmidt, M; Herrmann, S; Pomplun, J; Schmidt, F; Wohlfeil, B; Zschiedrich, L
2015-01-01
The finite-element method is a preferred numerical method when electromagnetic fields at high accuracy are to be computed in nano-optics design. Here, we demonstrate a finite-element method using hp-adaptivity on tetrahedral meshes for computation of electromagnetic fields in a device with rough textures. The method allows for efficient computations on meshes with strong variations in element sizes. This enables to use precise geometry resolution of the rough textures. Convergence to highly accurate results is observed.
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)
2013-11-15
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.
Mourad, Hashem M [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Addessio, Francis L [Los Alamos National Laboratory
2010-12-16
An explicit finite element formulation, used to study the behavior and failure mechanisms of metallic materials under high strain rate loading, is presented. The formulation is based on the assumed-strain approach of Fish and Belytschko [1988], which allows localization bands to be embedded within an element, thereby alleviating mesh sensitivity and reducing the required computational effort. The behavior of the material outside localization bands (and of the virgin material prior to the onset of strain localization) is represented using a Gurson-type coupled plasticity-damage model based on the work of Johnson and Addessio [1988]. Assuming adiabatic conditions, the response of the localization band material is represented by a set of constitutive equations for large elasticviscoplastic deformations in metals at high strain rates and high homologous temperatures (see Brown et al. [1989]). Computational results are compared to experimental data for different metallic alloys to illustrate the advantages of the proposed modeling strategy.
A topology-motivated mixed finite element method for dynamic response of porous media
Lotfian, Zahrasadat
2015-01-01
In this paper, we propose a numerical method for computing solutions to Biot's fully dynamic model of incompressible saturated porous media [Biot;1956]. Our spatial discretization scheme is based on the three-field formulation (u-w-p) and the coupling of a lowest order Raviart-Thomas mixed element [Raviart,Thomas;1977] for fluid variable fields (w, p ) and a nodal Galerkin finite element for skeleton variable field (u). These mixed spaces are constructed based on the natural topology of the variables; hence, are physically compatible and able to exactly model the kind of continuity which is expected. The method automatically satisfies the well known LBB (inf-sup) stability condition and avoids locking that usually occurs in the numerical computations in the incompressible limit and very low hydraulic conductivity. In contrast to the majority of approaches, our three-field formulation can fully capture dynamic behavior of porous media even in high frequency loading phenomena with considerable fluid acceleratio...
A Finite Quantum Gravity Field Theory Model
Jorge Alfaro; Pablo González; Ricardo Avila
2011-09-22
We discuss the quantization of Delta gravity, a two symmetric tensors model of gravity. This model, in Cosmology, shows accelerated expansion without a cosmological constant. We present the $\\tilde{\\delta}$ transformation which defines the geometry of the model. Then we show that all delta type models live at one loop only. We apply this to General Relativity and we calculate the one loop divergent part of the Effective Action showing its null contribution in vacuum, implying a finite model. Then we proceed to study the existence of ghosts in the model. Finally, we study the form of the finite quantum corrections to the classical action of the model.
Analysis of delamination growth with discontinuous finite elements
Remmers, Joris J C; Wells, G N; De Borst, R
of the incorporated interface elements is examined by means of a three point bending test. Conventional interface elements suffer from spurious stress oscillations for high ratios of dummy stiffnesses and the Young’s modulus of the continuum elements [2... than conventional interface elements, especially when geometrically nonlinearities are incorporated. Furthermore, the ele- ments can still be used in unstructured meshes. In the remainder of this paper, we will refer to this element type...
Finite element analysis of surface-stress effects in the Si lattice-parameter measurement
Sasso, Carlo; Massa, Enrico; Mana, Giovanni; Kuetgens, Ulrich
2013-01-01
A stress exists in solids surfaces, similarly to liquids, also if the underlying bulk material is stress-free. This paper investigates the surface stress effect on the measured value of the Si lattice parameter used to determine the Avogadro constant by counting Si atoms. An elastic-film model has been used to provide a surface load in a finite element analysis of the lattice strain of the x-ray interferometer crystal used to measure the lattice parameter. Eventually, an experiment is proposed to work a lattice parameter measurement out so that there is a visible effect of the surface stress.
A Method for Connecting Dissimilar Finite Element Meshes in Three Dimensions
Dohrmann, C.R.; Heinstein, M.W.; Key, S.W.
1998-11-12
A method is presented for connecting dissimilar finite element meshes in three dimensions. The method combines the concept of master and slave surfaces with the uniform strain approach for surface, corrections finite elements- By modifyhg the are made to element formulations boundaries of elements on the slave such that first-order patch tests are passed. The method can be used to connect meshes which use different element types. In addition, master and slave surfaces can be designated independently of relative mesh resolutions. Example problems in three-dimensional linear elasticity are presented.
Multigrid for Higher Order Discontinuous Galerkin Finite Elements Applied to Groundwater Flow
Bastian, Peter
Multigrid for Higher Order Discontinuous Galerkin Finite Elements Applied to Groundwater Flow Peter elements applied to the groundwater flow equation. It uses an incomplete LU decomposition on an element for diffusion problems has been formu- lated in [6]. 1.1 Notation In this paper we wish to solve the groundwater
Finite element thermomechanical simulation of droplets impacting on a rigid substrate
Bertagnolli, M.; Marchese, M.; Jacucci, G.; St. Doltsinis, I.; Noelting, S.
1994-12-31
The plasma spray process is a convenient way to coat a piece of material with a layer of another material, to protect the first from thermal shock or environmental degradation. Finite Element simulation techniques (FEM) for the spreading process of a ceramic liquid droplet impacting on a flat cold surface have been developed. The goal of the present investigation is (1) to predict the geometrical form of the splat as a function of process parameters, such as initial temperature and velocity, and (2) to follow the thermal field developing in the droplet up to solidification. A non-linear finite element procedure has been extended in order to model the complex physical phenomena involved in the impact process. The dynamic motion of the viscous melt in the drops as constrained by elastic surface tensions in interaction with the developing contact with the target, ultimately has been coupled to transient thermal phenomena accounting also for the solidification of the material. In a first model description, spherical particles of liquid ceramic of given temperature and velocity impact on a flat, cool rigid surface. The deformation of the splat geometry as well as the evolution of the thermal field within the splat are followed up to the final state and require adaptive discretization techniques. The authors discuss an utilization of the proposed model in correlating flattening degrees with the initial process parameters.
A Finite Element Method Using Singular Functions: Interface Problems
2008-03-06
The solution of the interface problem is only in H1+?(?) with ? > 0 possibly close to zero ...... To this end, let Th be a partition of the domain ? into triangular finite.
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
Adaptive High-order Finite Element Solution of Transient Elastohydrodynamic Lubrication
Walkley, Mark
Adaptive High-order Finite Element Solution of Transient Elastohydrodynamic Lubrication Problems H a new numerical method to solve transient line contact elastohydrodynamic lubrication (EHL) problems parameter dimensionless density 2 #12;1 Introduction Elastohydrodynamic Lubrication (EHL) problems have
Higher Order Discontinuous Finite Element Methods for Discrete Ordinates Thermal Radiative Transfer
Maginot, Peter G
2015-07-28
The linear discontinuous finite element method (LDFEM) is the current work horse of the radiation transport community. The popularity of LDFEM is a result of LDFEM (and its Q1 multi-dimensional extensions) being both ...
Miniature Hourglass Shaped Actuator Geometry Study Using A Finite Element Simulation
Elwell, Roston Clement
2011-08-08
This project investigated a miniature, hourglass-shaped actuator (MHA) and how its geometry affects performance. A custom, self-contained, finite-element simulation code predicts how each MHA deforms when pressurized ...
Bangerth, Wolfgang
Experimental Fluorescence Optical Tomography using Adaptive Finite Elements and Planar Illumination with Modulated Excitation Light Amit Joshia , Wolfgang Bangerthb , Alan B. Thompsona , and Eva M. Sevick adaptive discretization strategies. To date, the efficacy of adaptive mesh refinement techniques has yet
Least squares based finite element formulations and their applications in fluid mechanics
Prabhakar, Vivek
2009-05-15
In this research, least-squares based finite element formulations and their applications in fluid mechanics are presented. Least-squares formulations offer several computational and theoretical advantages for Newtonian as well as non-Newtonian fluid...
A Finite Element-Multibody Dynamics Co-simulation Methodology Applied to FAST
Suryakumar, Vishvas Samuel
2013-05-02
A co-simulation methodology is explored whereby a finite element code and a multi-body dynamics code featuring flexible cantilevered beams can be coupled and interactively executed. The floating frame of reference formulation is used to develop...
Gogineni, Sireesha
2011-10-21
The ballistic impact of Twaron CT709® plain weave fabrics is studied using an explicit finite element method. Many existing approximations pertaining to woven fabrics cannot adequately represent strain rate-dependent behavior exhibited by the Twaron...
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
2014-01-01
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 ...
Finite generation and geography of models
Kaloghiros, Anne-Sophie; Lazi?, Vladimir
2012-01-01
There are two main examples where a version of the Minimal Model Program can, at least conjecturally, be performed successfully: the first is the classical MMP associated to the canonical divisor, and the other is Mori Dream Spaces. In this paper we formulate a framework which generalises both of these examples. Starting from divisorial rings which are finitely generated, we determine precisely when we can run the MMP, and we show why finite generation alone is not sufficient to make the MMP work.
Finite Element Approximation of the Acoustic Wave Equation: Error Control and Mesh
Bangerth, Wolfgang
Finite Element Approximation of the Acoustic Wave Equation: Error Control and Mesh Adaptation of the Acoustic Wave Equation: Error Control and Mesh Adaptation Wolfgang Bangerth and Rolf Rannacher1 Institute@iwr.uni-heidelberg.de Abstract We present an approach to solving the acoustic wave equation by adaptive finite el- ement methods
Suo, Zhigang
A dynamic finite element method for inhomogeneous deformation and electromechanical instability Electromechanical instability Wrinkling Snap through a b s t r a c t We present a three-dimensional nonlinear finite the basis for needed computational tools that can elucidate the electromechanical behavior and properties
Finite element analysis of conjugate heat transfer in axisymmetric pipe flows
Fithen, Robert Miller
1987-01-01
FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MA STER... OF S CI EN CE August 1987 Major Subject: Mechanical Engineering FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Approved ss to style and content by: N. K. Anand (Chairman of Committee...
A finite element analysis of shrinkage stress fields in two-phase materials
Hall, Frank
1980-01-01
A FINITE ELEMENT ANALYSIS OF SHRINKAGE STRESS FIELDS IN TWO-PHASE MATERIALS A Thesis by FRANK HALL Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1980 Maj or Subj ect: Mechanical Engineering A FINITE ELEMENT ANALYSIS OF SHRINKAGE STRESS FIELDS IN TWO-PHASE MATERIALS A Thesis FRANK HALL Approved as to style and content by: (Chairman of Committee) (Member) (Member) (Member) (H d...
Partially Penalized Immersed Finite Element Methods for Parabolic ...
2015-01-26
to parabolic interface problem together with the Laplacian transform. Parabolic .... We then partition K into two sub-elements K? and K+ by the line segment ...
FINITE ELEMENTS AND FINITE DIFFERENCE HUMAN HEAD MODELING: FORWARD PROBLEM
Lowd, Daniel
.T. Vetterling, B.P. Flannery, The Numerical Recipes in C: The art of Scientific Computing, 2nd edition. New York/MEG Fundamental problems in electroencephalography (EEG) and magnetoencephalograpy (MEG), in particular , source DISCUSSION AND FUTURE RESEARCH When using FD methods one should be aware about the following "pros" and "cons
Structural Mechanics & Solid Mechanics A finite element toolbox to MATLAB
Ehrhardt, Matthias
Structural Mechanics & Solid Mechanics Department of Mechanics and Materials CALFEM A finite.3 Copyright Â© 1999 by Structural Mechanics, LTH, Sweden. Printed by JABE Offset, Lund, Sweden. ISRN LUTVDG/TVSM--99/9001--SE (1-265) ISSN 0281-6679 Department of Mechanics and Materials Structural Mechanics #12;The
Numerical Analysis of a Mixed Finite Element Method for a FlowTransport Problem
Chou, So-Hsiang
a waste disposal problem in which high level radioactive waste is buried in a salt dome, the salt dissolves to create a brine, radioactive elements decay to generate heat, and radionuclides are transportedNumerical Analysis of a Mixed Finite Element Method for a FlowTransport Problem S. H. CHOU AND Q
Finite Model Finding for Parameterized Verification
Lisitsa, Alexei
2010-01-01
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 ...
Unconstrained paving and plastering method for generating finite element meshes
Staten, Matthew L. (Albuquerque, NM); Owen, Steven J. (Albuquerque, NM); Blacker, Teddy D. (Albuquerque, NM); Kerr, Robert (Albuquerque, NM)
2010-03-02
Computer software for and a method of generating a conformal all quadrilateral or hexahedral mesh comprising selecting an object with unmeshed boundaries and performing the following while unmeshed voids are larger than twice a desired element size and unrecognizable as either a midpoint subdividable or pave-and-sweepable polyhedra: selecting a front to advance; based on sizes of fronts and angles with adjacent fronts, determining which adjacent fronts should be advanced with the selected front; advancing the fronts; detecting proximities with other nearby fronts; resolving any found proximities; forming quadrilaterals or unconstrained columns of hexahedra where two layers cross; and establishing hexahedral elements where three layers cross.
FEHM (Finite Element Heat and Mass Transfer Code)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunitiesofExtrans - Permeation Measurement2TargetedFEHM (Finite
Wang, Ji; Sun, Qiang; Wu, Rongxing; Huang, Bin; Du, Jianke; Xiang, Wei
2015-01-01
The finite element analysis of high frequency vibrations of quartz crystal plates is a necessary process required in the design of quartz crystal resonators of precision types for applications in filters and sensors. The anisotropic materials and extremely high frequency in radiofrequency range of resonators determine that vibration frequency spectra are complicated with strong couplings of large number of different vibration modes representing deformations which do not appear in usual structural problems. For instance, the higher-order thickness-shear vibrations usually representing the sharp deformation of thin plates in the thickness direction, expecting the analysis is to be done with refined meshing schemes along the relatively small thickness and consequently the large plane area. To be able to represent the precise vibration mode shapes, a very large number of elements are needed in the finite element analysis with either the three-dimensional theory or the higher-order plate theory, although considera...
ADAPTIVE DISCONTINUOUS GALERKIN FINITE ELEMENT METHODS FOR NONLINEAR HYPERBOLIC CONSERVATION
Hartmann, Ralf
RALF HARTMANN #3; AND PAUL HOUSTON y Abstract. We consider the a posteriori error analysis and adaptive, University of Heidelberg, Im Neuenheimer Feld 293, D-69120 Heidelberg, Germany (e-mail: Ralf.Hartmann-mail: Paul.Houston@mcs.le.ac.uk). 1 #12; 2 R. HARTMANN and P. HOUSTON estimates, the element residuals
The strong Bass conjecture for group elements of finite order and for residually finite groups
Schick, Thomas
groups Thomas Schick* Last compiled October 5, 2000; last edited Oct 5~g __________________________* e-mail: thomas.schick@math.uni-muenster.de www: http://wwwmath.uni-muenster.de/u/lueck/schick Thomas Schick If P is a finitely generated projective kG-module, choose a "complement" Q such that P
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
A Finite Element Method for Fully Nonlinear and General Quasilinear Elliptic Problems
Pryer, Tristan
2011-01-01
We present a continuous finite element method for fully nonlinear elliptic equations. The tools we use are (1) a Newton linearisation, yielding a sequence of linear PDEs in nonvariational form and (2) the discretisation proposed in [LP11] allowing us to work directly on the strong form of a linear PDE. An added benefit to making use of this discretisation method is that a recovered (finite element) Hessian is a biproduct of the solution process. Benchmark numerical results illustrate the convergence properties of the scheme for some test problems.
A VECTOR FINITE ELEMENT TIME-DOMAIN METHOD FOR ...
SIAM (#1) 1035 2001 Apr 10 12:32:38
2001-08-14
voltage standing wave ratio (VSWR), and reflection coefficient are shown in Table 8. .... C. D. Turner, VOLMAX: A solid model based transient volumetric Maxwell.
Full wave simulation of waves in ECRIS plasmas based on the finite element method
Torrisi, G.; Mascali, D.; Neri, L.; Castro, G.; Patti, G.; Celona, L.; Gammino, S.; Ciavola, G.; Di Donato, L.; Sorbello, G.; Isernia, T.
2014-02-12
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.
Wells, G N
2009-10-28
This solver is in support of the paper 'Analysis of an interface stabilised finite element method: The advection-diffusion-reaction equation', by Garth N. Wells...
Li, H.; Li, G., E-mail: gli@clemson.edu [College of Engineering and Science, Clemson University, Clemson, South Carolina 29634-0921 (United States)
2014-08-28
An accelerated Finite Element Contact Block Reduction (FECBR) approach is presented for computational analysis of ballistic transport in nanoscale electronic devices with arbitrary geometry and unstructured mesh. Finite element formulation is developed for the theoretical CBR/Poisson model. The FECBR approach is accelerated through eigen-pair reduction, lead mode space projection, and component mode synthesis techniques. The accelerated FECBR is applied to perform quantum mechanical ballistic transport analysis of a DG-MOSFET with taper-shaped extensions and a DG-MOSFET with Si/SiO{sub 2} interface roughness. The computed electrical transport properties of the devices obtained from the accelerated FECBR approach and associated computational cost as a function of system degrees of freedom are compared with those obtained from the original CBR and direct inversion methods. The performance of the accelerated FECBR in both its accuracy and efficiency is demonstrated.
stabilized finite element methods for coupled geomechanics and ...
7.19 Water saturation map by FCM and FEAST model at t = 1600 days . 110 .... The Wilmington oil field is located in Long Beach, California. Subsidence was first.
Early Finite Element Research at University of California at Berkeley ...
professionally prior to the publication of a formal paper... ... Next couple of decades or so witnessed a great by Hrennikoff [1] and McHenry[2], to model membrane and plate bending parts of the structure. However Turner, head of the Structural Dynamics Unit, and was asked to calculate the bending and torsional
AN hp FINITE ELEMENT METHOD TO SOLVE A FLUID-SOLID VIBRATION PROBLEM
Rodríguez, Rodolfo
AN hp FINITE ELEMENT METHOD TO SOLVE A FLUID-SOLID VIBRATION PROBLEM CLAUDIO PADRA, RODOLFO RODR´IGUEZ , AND MARIO SCHEBLE § Abstract. This paper deals with a two-dimensional fluid-solid vibration problem arising from nuclear engineering: the vibration of elastically mounted tubes immersed in a cavity filled
Finite Element Method for Epitaxial Growth with Attachment-Detachment Kinetics
Li, Bo
growth of thin films. Epitaxial growth is a technology for growing single crystal thin filmsFinite Element Method for Epitaxial Growth with Attachment-Detachment Kinetics Eberhard B in epitaxial growth. Such problems consist of an adatom (adsorbed atom) diffusion equation on terraces
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations with
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations in time 5 3 Specific applications 10 3.1 The acoustic wave equation, for the first time, to second order wave equations including elastodynamics with and without Kelvin
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations with
High Order Space-Time Finite Element Schemes for Acoustic and Viscodynamic Wave Equations applications are to the acoustic wave equation and to elastodynamics. We also build in the well-known Kelvin for decoupled DGFEM in time 6 3 Specific applications 10 3.1 The acoustic wave equation
Ewing, Richard E.
A ThreeÂDimensional Finite Element Simulation for Transport of Nuclear Waste ContaminationÂwaste contamination in threeÂdimensional porous media are presented with a description of linearization techniques contamination involving the transport of fluid, heat, brine, and traceÂspecies radionuclides by logically
Shape Design with Great Geometrical Deformations Using Continuously Moving Finite Element Nodes
Ring, Wolfgang
Shape Design with Great Geometrical Deformations Using Continuously Moving Finite Element Nodes B, University of Graz, Heinrichstrasse 36, AÂ8010 Graz, Austria Abstract --- In this paper design sensitivity on the design paÂ rameters. Since design sensitivity analysis is mainly applicable to optimization problems
Shape Design with Great Geometrical Deformations Using Continuously Moving Finite Element Nodes
Ring, Wolfgang
Shape Design with Great Geometrical Deformations Using Continuously Moving Finite Element Nodes B of Graz, Heinrichstrasse 36, A-8010 Graz, Austria Abstract | In this paper design sensitivity anal- ysis, it is necessary to assume a continuously di erentiable dependence of the sti ness matrix on the design pa
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
An Online Data Access System for a Finite Element Program , David Liu2
Stanford University
management in FEA programs still mainly rely on file systems. The prevailing data structures are based of the problems encountered by the prevailing data management based on file systems. Current trend sees retrieval. The online data access system gives great flexibility to the management of data in finite element
Solid-mechanics finite element simulations of the draping of fabrics: a sensitivity analysis
Frey, Pascal
Solid-mechanics finite element simulations of the draping of fabrics: a sensitivity analysis L. Dong, C. Lekakou*, M.G. Bader School of Mechanical and Materials Engineering, University of Surrey into a "hat" shape, combining a hemispherical cup with a wide flat rim. A mechanical approach is adopted using
FINITE ELEMENT ANALYSIS OF A BENDING MOMENT FORMULATION FOR THE VIBRATION PROBLEM OF A
RodrÃguez, Rodolfo
FINITE ELEMENT ANALYSIS OF A BENDING MOMENT FORMULATION FOR THE VIBRATION PROBLEM OF A NON-HOMOGENEOUS TIMOSHENKO BEAM FELIPE LEPE, DAVID MORA, AND RODOLFO RODRÂ´IGUEZ Abstract. In this paper we analyze a low-homogeneous Timoshenko beam. We consider a formulation in which the bending moment is introduced as an additional unknown
Wadley, Haydn
The impact of sand slugs against beams and plates: Coupled discrete particle/finite element/continuum coupling Dynamic loading a b s t r a c t The impact of a slug of dry sand particles against a metallic for shock mitigation. The sand particles interact via a combined linear-spring-and-dashpot law whereas
Advanced finite-element methods for design and analysis of nanooptical structures: Applications
Burger, S; Pomplun, J; Blome, M; Schmidt, F; 10.1117/12.2001094
2013-01-01
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.
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
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
Surface Based Atlas Matching of the Brain Using Deformable Surfaces and Volumetric Finite Elements
Surface Based Atlas Matching of the Brain Using Deformable Surfaces and Volumetric Finite Elements onto the target image and interpolate the surface displacement to obtain a fully volumetric mapping (e.g. [3]). Volumetric methods compute a deformation field that minimizes a similarity criterion between
STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES Tayfun E boundaries and interfaces. The methods developed can be classified into two main categories: interface-tracking and interface-capturing techniques. Both classes of techniques are based on sta- bilized formulations
STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES of flow problems with moving boundaries and interfaces. The methods developed are categorized into two classes: interface-tracking and interface-capturing techniques. Both classes of techniques are based
Finite element analyses of tool stresses in metal cutting processes
Kistler, B.L.
1997-01-01
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.
Recanati, Catherine
A finite element method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein Abstract Numerical computations of stationary states of fastrotating BoseEinstein condensates require rotation rates). Key words: Gross--Pitaevskii equation, finite element method, mesh adaptivity, BoseEinstein
Cut-on cut-off transition in flow ducts: comparing multiple-scales and finite-element solutions
Eindhoven, Technische Universiteit
Cut-on cut-off transition in flow ducts: comparing multiple-scales and finite-element solutions Eindhoven, The Netherlands. The phenomenon of cut-on cut-off transition of acoustic modes in ducts with mean from a numerical finite-element method. The analytical solution, derived for an arbitrary duct
Müftü, Sinan
An Adaptive Finite Element Startegy for Analysis of Air Lubrication in the Head-Disk Interface, interface de tête-disque KEYWORDS: air lubrication, finite elements, adaptive mesh, head-disk interface #12). Air lubrication between the rotating disk and the slider is critical to maintain this gap; a delicate
Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur
Ascenzi, Maria-Grazia, E-mail: mgascenzi@mednet.ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States)] [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Kawas, Neal P., E-mail: nealkawas@ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Lutz, Andre, E-mail: andre.lutz@hotmail.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Kardas, Dieter, E-mail: kardas@ibnm.uni-hannover.de [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany)] [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany); Nackenhorst, Udo, E-mail: nackenhorst@ibnm.uni-hannover.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Keyak, Joyce H., E-mail: jhkeyak@uci.edu [Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697-5000 (United States)
2013-07-01
We present an innovative method to perform multi-scale finite element analyses of the cortical component of the femur using the individual’s (1) computed tomography scan; and (2) a bone specimen obtained in conjunction with orthopedic surgery. The method enables study of micro-structural characteristics regulating strains and stresses under physiological loading conditions. The analysis of the micro-structural scenarios that cause variation of strain and stress is the first step in understanding the elevated strains and stresses in bone tissue, which are indicative of higher likelihood of micro-crack formation in bone, implicated in consequent remodeling or macroscopic bone fracture. Evidence that micro-structure varies with clinical history and contributes in significant, but poorly understood, ways to bone function, motivates the method’s development, as does need for software tools to investigate relationships between macroscopic loading and micro-structure. Three applications – varying region of interest, bone mineral density, and orientation of collagen type I, illustrate the method. We show, in comparison between physiological loading and simple compression of a patient’s femur, that strains computed at the multi-scale model’s micro-level: (i) differ; and (ii) depend on local collagen-apatite orientation and degree of calcification. Our findings confirm the strain concentration role of osteocyte lacunae, important for mechano-transduction. We hypothesize occurrence of micro-crack formation, leading either to remodeling or macroscopic fracture, when the computed strains exceed the elastic range observed in micro-structural testing.
Swaddiwudhipong, S; Liu, Z S
2012-01-01
Finite element method (FEM) suffers from a serious mesh distortion problem when used for high velocity impact analyses. The smooth particle hydrodynamics (SPH) method is appropriate for this class of problems involving severe damages but at considerable computational cost. It is beneficial if the latter is adopted only in severely distorted regions and FEM further away. The coupled smooth particle hydrodynamics - finite element method (SFM) has been adopted in a commercial hydrocode LS-DYNA to study the perforation of Weldox 460E steel and AA5083-H116 aluminum plates with varying thicknesses and various projectile nose geometries including blunt, conical and ogival noses. Effects of the SPH domain size and particle density are studied considering the friction effect between the projectile and the target materials. The simulated residual velocities and the ballistic limit velocities from the SFM agree well with the published experimental data. The study shows that SFM is able to emulate the same failure mechan...
The inclusion of damage effects in an incremental finite element analysis of composite plates
Kilpatrick, Mark Christopher
1984-01-01
, boron, carbon, graphite) supported in polymeric matrices and later ln light weight metal matrices. (mme- diatelyo the analysis of fiber composites began. Analyses of Fiber composites are approached from the micro- or macro-mechanics view- point... for ihe degree of MASTER OF SCIENCE December 1984 Major Subject: Mechanical Engineering THE INCLUSION OF DAMAGE EFFECTS IN AN INCREMENTAL FINITE ELEMENT ANALYSIS OF COMPOSITE PLATES A Thesis by MARK CHRISTOPHER KILPATRICK Approved as to style...
Three dimensional finite element analysis of the flow of polymer melts
Jimack, Peter
Three dimensional finite element analysis of the flow of polymer melts R. Tencheva , T. Goughb , O.G, LS2 9JT, UK. b School of Engineering, Design & Technology, University of Bradford, Bradford, BD7 1DP.g.harlen@leeds.ac.uk (O.G. Harlen), p.k.jimack@leeds.ac.uk (P.K. Jimack), h.klein@leeds.ac.uk (D.H. Klein), m
Oelgaard, Kristian B; Wells, G N
2009-07-20
Optimisations for quadrature representations of finite element tensors through automated code generation KRISTIAN B. ØLGAARD Faculty of Civil Engineering and Geosciences Delft University of Technology and GARTH N. WELLS Department of Engineering... differential equations while achieving optimal or near-optimal run time performance is a possibility offered by K.B. Ølgaard, Faculty of Civil Engineering and Geosciences, Delft University of Technology Stev- inweg 1, 2628 CN Delft, Netherlands. Email: k.b...
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
2009-01-01
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.
Grujicic, Mica
2005-01-01
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
Zingan, Valentin Nikolaevich
2012-07-16
This work develops a discontinuous Galerkin finite element discretization of non- linear hyperbolic conservation equations with efficient and robust high order stabilization built on an entropy-based artificial viscosity approximation...
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
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;
Modeling and Driving Piezoelectric Resonant Blade Elements
Modeling and Driving Piezoelectric Resonant Blade Elements Sam Ben-Yaakov* and Natan Krihely Power@ee.bgu.ac.il ; Website: http://www.ee.bgu.ac.il/~pel Abstract-- Piezoelectric Resonant Blade elements (PRB) are useful in applications such as light choppers, laser beam scanners, fans and others. Three methods are proposed
Finite element simulations of compositionally graded InGaN solar cells G.F. Brown a,b,n
Wu, Junqiao
for cheap multi-junction solar cells [4]. Previous simulations have shown that double-junction InxGa1ÀxFinite element simulations of compositionally graded InGaN solar cells G.F. Brown a,b,n , J.W. Ager conversion efficiency of compositionally graded InxGa1ÀxN solar cells was simulated using a finite element
Discrete element modelling of cementitious materials
Brown, Nicholas John
2013-07-01
This thesis presents a new bonded particle model that accurately predicts the wideranging behaviour of cementitious materials. There is an increasing use of the Discrete Element Method (DEM) to study the behaviour of ...
Higher-Order Spectral/HP Finite Element Technology for Structures and Fluid Flows
Vallala, Venkat Pradeep
2013-06-20
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 ...
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)
2011-05-04
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
2006-04-06
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.
Analysis of an interface stabilised finite element method: The advection-diffusion-reaction equation
Wells, G N
2009-10-29
is denoted by ?0. Adjacent cells are considered to share a common facet F . The bilinear and linear forms for the advection-diffusion-reaction equation are now introduced. Using the notation w = (w, w¯) and v = (v, v¯), consider the bilinear form: B (w... ? h , the finite element problem of interest reads: find uh ?W ?h such that B (uh,vh) = L (vh) ?vh ?W ?h . (2.8) Noteworthy in the bilinear form is that the functions wh, which are discontinuous across cell facets, are not linked directly across facets...
Local Jacobi Operators and Applications to the p-version of Finite Element Method in Two Dimensions
Guo, Benqi
Local Jacobi Operators and Applications to the p-version of Finite Element Method in Two Dimensions Benqi Guo Ivo Babuska Abstract Based on Jacobi projection operators p, on elements and edges we have designed local Jacobi operators j for smooth and singular solution on each triangular and quadrilateral
David L. Meier
1998-11-10
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.
Circuit level modeling of inductive elements
Muyshondt, G.P.; Portnoy, W.M.
1989-01-01
Design and analysis of spacecraft power systems have been difficult to perform because of the lack of circuit level models for nonlinear inductive elements. This paper reviews some of the models which have been proposed, their limitations, and applications. An improved saturation dependent model will be described. The model has been implemented in SPICE and with a commercial circuit program and demonstrated to be satisfactory in both implementations. 3 refs., 9 figs.
Nuclear Matter and Finite Nuclei in the Effective Chiral Model
Sahu, P K; Ohnishi, A
2009-01-01
We systematically investigate the vacuum stability and nuclear properties in the effective chiral model with higher order terms in $\\sigma$. We evaluate the model parameters by considering the saturation properties of nuclear matter as well as the normal vacuum to be globally stable at zero and finite baryon densities. We can find parameter sets giving moderate equations of state, and apply these models to finite nuclei.
A Generalized Multiscale Finite Element Method for Poroelasticity Problems I: Linear Problems
Brown, Donald L
2015-01-01
In this paper, we consider the numerical solution of poroelasticity problems that are of Biot type and develop a general algorithm for solving coupled systems. We discuss the challenges associated with mechanics and flow problems in heterogeneous media. The two primary issues being the multiscale nature of the media and the solutions of the fluid and mechanics variables traditionally developed with separate grids and methods. For the numerical solution we develop and implement a Generalized Multiscale Finite Element Method (GMsFEM) that solves problem on a coarse grid by constructing local multiscale basis functions. The procedure begins with construction of multiscale bases for both displacement and pressure in each coarse block. Using a snapshot space and local spectral problems, we construct a basis of reduced dimension. Finally, after multiplying by a multiscale partitions of unity, the multiscale basis is constructed in the offline phase and the coarse grid problem then can be solved for arbitrary forcin...
Evaluation of the matrix exponential function using finite elements in time
Gebremedhin, D H; Zhang, X; Wynn, A; Tanaka, G
2008-01-01
The evaluation of a matrix exponential function is a classic problem of computational linear algebra. Many different methods have been employed for its numerical evaluation [Moler C and van Loan C 1978 SIAM Review 20 4], none of which produce a definitive algorithm which is broadly applicable and sufficiently accurate, as well as being reasonably fast. Herein, we employ a method which evaulates a matrix exponential as the solution to a first-order initial value problem in a fictitious time variable. The new aspect of the present implementation of this method is to use finite elements in the fictitious time variable. [Weatherford C A, Red E, and Wynn A 2002 Journal of Molecular Structure 592 47] Then using an expansion in a properly chosen time basis, we are able to make accurate calculations of the exponential of any given matrix as the solution to a set of simultaneous equations.
Evaluation of the matrix exponential function using finite elements in time
D H Gebremedhin; C A Weatherford; X Zhang; A Wynn III; G Tanaka
2008-11-17
The evaluation of a matrix exponential function is a classic problem of computational linear algebra. Many different methods have been employed for its numerical evaluation [Moler C and van Loan C 1978 SIAM Review 20 4], none of which produce a definitive algorithm which is broadly applicable and sufficiently accurate, as well as being reasonably fast. Herein, we employ a method which evaulates a matrix exponential as the solution to a first-order initial value problem in a fictitious time variable. The new aspect of the present implementation of this method is to use finite elements in the fictitious time variable. [Weatherford C A, Red E, and Wynn A 2002 Journal of Molecular Structure 592 47] Then using an expansion in a properly chosen time basis, we are able to make accurate calculations of the exponential of any given matrix as the solution to a set of simultaneous equations.
Finite element residual stress analysis of induction heating bended ferritic steel piping
Kima, Jong Sung; Kim, Kyoung-Soo; Oh, Young-Jin; Chang, Hyung-Young; Park, Heung-Bae
2014-10-06
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 three TVA dams with alkali-aggregate reaction
Grenoble, B.A.; Meisenheimer, J.K.; Wagner, C.D.; Newell, V.A.
1995-12-31
Three large Tennessee Valley Authority (TVA) dams are currently experiencing problems caused by alkali-aggregate reaction (AAR). Since the fall of 1990, engineers in Stone & Webster`s Denver, Colorado office have been working with TVA to evaluate how AAR is affecting the dams and to identify measures for controlling the adverse effects of the concrete growth. This paper provides an overview of how finite element analysis is being used to understand the affects of AAR on these structures and to evaluate alternatives for minimizing the adverse effects of the concrete growth. Work on Hiwassee Dam is essentially complete, while that on the Chickamauga and Fontana Projects is still in progress. Consequently, this paper will focus primarily on Hiwassee Dam. The ongoing work on the other two projects will only be discussed briefly.
Comparison of methods for solving nonlinear finite-element equations in heat transfer
Cort, G.E.; Graham, A.L.; Johnson, N.L.
1981-01-01
We have derived two new techniques for solving the finite-element heat-transfer equations with highly nonlinear boundary conditions and material properties. When compared with the more commonly employed successive substitution and Newton-Raphson procedures, the new methods speed convergence rates and simultaneously increase the radius of convergence. We have observed reductions in computation time in excess of 80% when the new techniques are employed. The first method accelerates the standard Newton-Raphson approach when the degree of the nonlinearity is known (for example, radiation boundary conditions or a prescribed temperature dependence in the thermal conductivity). The second technique employs feedback to regulate the solution algorithm during execution. Comparisons of these techniques are given for several practical examples.
Ewing, Richard E.
A ThreeÂDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination for transport of nuclearÂwaste contamination in threeÂdimensional porous media are presented with a description waste contamination involving the transport of fluid, heat, brine, and traceÂspecies radionuclides
Tezduyar, Tayfun E.
Chapter 17 in Encyclopedia of Computational Mechanics, Volume 3: Fluids Finite Element Methods surfaces, two-fluid interfaces, fluidobject and fluidstructure in- teractions, and moving mechanical in Encyclopedia of Computational Mechanics, Volume 3: Fluids (eds. E. Stein, R. De Borst and T.J.R. Hughes), John
Patzek, Tadeusz W.
the geomechanics of oil and gas reservoirs. The fragile microstructure of some rocks makes it difficult to predict of Steel, Aluminum, Concrete, etc. Moreover, the pattern of rock damage in oil and gas reservoirsFinite Element Solution of Nonlinear Transient Rock Damage with Application in Geomechanics of Oil
Incorporation and modification of a shear deformable finite element into MARC
Hofman, Brad Burdell
1996-01-01
The proposed research focuses on implementing an existing shear deformable composite element as a user element in MARC[]. Furthermore, the element is enhanced by developing an algorithm to accommodate variable thickness within an element...
X. Frank Xu
2010-03-30
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.
Quinones, Armando, Sr. (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2008-08-01
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).
Elgeti, Stefanie
2015-01-01
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 ...
Zhou, Jack
"FINITE ELEMENT ANALYSIS ASSISTED HOT BAR BLADE DESIGN," Jack. Zhou, Li Zhuang, Zongyan He, Maryland, June 2000. FINITE ELEMENT ANALYSIS ASSISTED HOT BAR BLADE DESIGN Jack. Zhou, Li Zhuang in fabrication of cellular phones for many years. The existing hot bar blade design has two defects
E. Sun, P. Brindza, S. Lassiter, M. Fowler, E. Xu
2010-06-01
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.
Nguyen, Dang Van; Li, Jing-Rebecca; Grebenkov, Denis; Le Bihan, Denis
2014-04-15
The complex transverse water proton magnetization subject to diffusion-encoding magnetic field gradient pulses in a heterogeneous medium can be modeled by the multiple compartment Bloch–Torrey partial differential equation (PDE). In addition, steady-state Laplace PDEs can be formulated to produce the homogenized diffusion tensor that describes the diffusion characteristics of the medium in the long time limit. In spatial domains that model biological tissues at the cellular level, these two types of PDEs have to be completed with permeability conditions on the cellular interfaces. To solve these PDEs, we implemented a finite elements method that allows jumps in the solution at the cell interfaces by using double nodes. Using a transformation of the Bloch–Torrey PDE we reduced oscillations in the searched-for solution and simplified the implementation of the boundary conditions. The spatial discretization was then coupled to the adaptive explicit Runge–Kutta–Chebyshev time-stepping method. Our proposed method is second order accurate in space and second order accurate in time. We implemented this method on the FEniCS C++ platform and show time and spatial convergence results. Finally, this method is applied to study some relevant questions in diffusion MRI.
Bandaru, Vinodh; Krasnov, Dmitry; Schumacher, Jörg
2015-01-01
A conservative coupled finite difference-boundary element computational procedure for the simulation of turbulent magnetohydrodynamic flow in a straight rectangular duct at finite magnetic Reynolds number is presented. The flow is assumed to be periodic in the streamwise direction and is driven by a mean pressure gradient. The duct walls are considered to be electrically insulating. The co-evolution of the velocity and magnetic fields as described respectively by the Navier-Stokes and the magnetic induction equations, together with the coupling of the magnetic field between the conducting domain and the non-conducting exterior is solved using the magnetic field formulation. The aim is to simulate localized magnetic fields interacting with turbulent duct flow. Detailed verification of the implementation of the numerical scheme is conducted in the limiting case of low magnetic Reynolds number by comparing with the results obtained using a quasistatic approach that has no coupling with the exterior. The rigorous...
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01
Earthquake." Journal of Soil Mechanics and FoundationsConference on Soil Mechanics and Foundation Engineering,Journal of the Soil Mechanics and Foundations Division, 89(
Finite element modeling of SHTE and PSVTM electroseismics
Fabio I. Zyserman
2010-10-07
Theory and application to geothermal systems. Journal Geophysical Research. 104, 20033–20048. Santos, J.E., 1998. Global and domain-decomposed mixed ...
Finite element modeling of heat and mass transport in aquifers
Grubaugh, Elston Kent
1980-01-01
3C ac aq 3N. 1 ay aN. 1 az aN. 3 3y aN. 1 az The left hand side can be evaluated since the basis functions are specified in local coordinates. The matrix [J], known as the "Jacobian matrix", can also be formed in terms of local... N. when iso- 1 parametric formulation is used, J may be written as, aN. 1 z ? x. az i BN 1 z ? x. an i aN. 1 z ? y. az i' aN. 1 z ? y. an i aN. 1 z ? z. az i BN. 1 z ? z. an BN. z ? x. 1 ac i aN. 1 z ? y. ac i aN. 1...
Notes 12. Finite element modeling of mechanical systems
San Andres, Luis
2008-01-01
Engineering calculations on PC's are undergoing a revolution with the advent of spreadsheet programs. The author has found that virtually all of the energy analysis types of programs can be cast into spreadsheet methods ...
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01
and computed excess pore pressure time histories. .and computed excess pore pressure time histories. ..time histories. Excess pore pressure (KPa) PP1 (1.0m depth)
A Finite Element Model Of Self-Resonating Bimorph Microcantilever...
Office of Scientific and Technical Information (OSTI)
parameters on the frequency and magnitude of temperature cycling and the efficiency of energy recycling using the proposed structure has been investigated. Results show that...
Finite element modeling of hydraulic fracturing in 3D
2013-03-22
Mar 22, 2013 ... The paper is organized as followszThe partitioning of the stress .... given by Young's modulus E and Poisson ratio v as. vE E .... angled bend.
A Mixed Finite Element Framework for Modeling Coupled Fluid Flow ...
Birendra Jha
2005-10-03
from being used routinely in oil and gas reservoir simulation studies. ..... 6.8 Example 8 - Input parameters for Unstructured Grid field simulation. 117 xi .... water is known to cause surface subsidence in Santa Clara and San Joaquin Valleys.
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
1980-01-01
Solar energy is a promising alternate energy source for space heating. A method of economic long term solar energy storage is needed. Researchers have proposed storing solar energy by injecting hot water heated using solar collectors...
Optimization of superconducting magnetic bearings using finite element modeling
Bryslawskyj, Jason (Jason Bogdan)
2009-01-01
This project investigated the possibility of using superconducting bearings in large (3 - 100 MW) electric drives. Superconducting bearings are used to levitate the rotors inside electric drives via the Meiissner effect, ...
Finite element modeling of flow through ceramic pot filters
Kelly, Anna C
2013-01-01
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 ...
Finite-element harmonic experiments to model fractured induced ...
santos
Mar 10, 2014 ... Fractured hydrocarbon reservoirs have been the subject of interest in explo- ... since these factors control hydrocarbon production [2]. This is ...
Modeling dislocations in a polycrystal using the generalized finite element
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport)Fermentative Activity on Fateof StarThermosyphonsArticle)
Modeling dislocations in a polycrystal using the generalized finite element
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport)Fermentative Activity on Fateof
Hoffman, E.L.; Ammerman, D.J.
1993-08-01
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
2005-08-24
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.
Iskander, S.K.
1981-02-01
Two finite element (FE) approaches were used to calculate opening mode I stress intensity factors (K/sub I/) in two- or three-dimensional (2-D and 3-D) problems for the Heavy-Section Steel Technology (HSST) program. For problems that can be modeled in two dimensions, two techniques were used. One of these may be termed an ''energy release rate'' technique, and the other is based on the classical near-tip displacement and stress field equations. For three-dimensional problems, only the latter technique was used. In the energy release technique, K/sub I/ is calculated as the change in potential energy of the structure due to a small change in crack length. The potential energy is calculated by the FE method but without completely solving the system of linear equations for the displacements. Furthermore, the system of linear equations is only slightly perturbed by the change in crack length and, therefore, many computations need not be repeated for the second structure with the slight change in crack length. Implementation of these last two items has resulted in considerable savings in the calculation of K/sub I/ as compared to two complete FE analyses. These ideas are incorporated in the FMECH code. The accuracy of the methods has been checked by comparing the results of the two approaches with each other and with closed form solutions. It is estimated that the accuracy of the results is about +-5%.
Woodward, Carol S.; Gardner, David J.; Evans, Katherine J.
2015-01-01
Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.
Gardner, David; Woodward, Carol S.; Evans, Katherine J
2015-01-01
Efficient solution of global climate models requires effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a time step dictated by accuracy of the processes of interest rather than by stability governed by the fastest of the time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton s method is applied for these systems. Each iteration of the Newton s method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but this Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite-difference which may show a loss of accuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite-difference approximations of these matrix-vector products for climate dynamics within the spectral-element based shallow-water dynamical-core of the Community Atmosphere Model (CAM).
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Woodward, Carol S.; Gardner, David J.; Evans, Katherine J.
2015-01-01
Efficient solutions of global climate models require effectively handling disparate length and time scales. Implicit solution approaches allow time integration of the physical system with a step size governed by accuracy of the processes of interest rather than by stability of the fastest time scales present. Implicit approaches, however, require the solution of nonlinear systems within each time step. Usually, a Newton's method is applied to solve these systems. Each iteration of the Newton's method, in turn, requires the solution of a linear model of the nonlinear system. This model employs the Jacobian of the problem-defining nonlinear residual, but thismore »Jacobian can be costly to form. If a Krylov linear solver is used for the solution of the linear system, the action of the Jacobian matrix on a given vector is required. In the case of spectral element methods, the Jacobian is not calculated but only implemented through matrix-vector products. The matrix-vector multiply can also be approximated by a finite difference approximation which may introduce inaccuracy in the overall nonlinear solver. In this paper, we review the advantages and disadvantages of finite difference approximations of these matrix-vector products for climate dynamics within the spectral element shallow water dynamical core of the Community Atmosphere Model.« less
Insider Models with Finite Utility in Markets with Jumps
Kohatsu-Higa, Arturo; Yamazato, Makoto
2011-10-15
In this article we consider, under a Levy process model for the stock price, the utility optimization problem for an insider agent whose additional information is the final price of the stock blurred with an additional independent noise which vanishes as the final time approaches. Our main interest is establishing conditions under which the utility of the insider is finite. Mathematically, the problem entails the study of a 'progressive' enlargement of filtration with respect to random measures. We study the jump structure of the process which leads to the conclusion that in most cases the utility of the insider is finite and his optimal portfolio is bounded. This can be explained financially by the high risks involved in models with jumps.
Analysis and behavioral modeling of the Finite State Machines of the Xpress Transfer Protocol
Madduri, Venkateswara Rao
1994-01-01
. This research focuses on the analysis and behavioral modeling of the Finite State Machines of the XTP. The simulation language used is the Verilog Hardware Description Language. We have modeled XTP Finite State Machines as a set of communicating, concurrent...
Fournier, John J.F.
Introduction to nuclear fusion Modelling Finite volume scheme Formal asymptotics Summary Magnetized, Committee Member November 28, 2014 Michael Lindstrom Magnetized Target Fusion #12;Introduction to nuclear Target Fusion #12;Introduction to nuclear fusion Modelling Finite volume scheme Formal asymptotics
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
Notes 01. Modeling of mechanical (lumped parameter) elements
San Andres, Luis
2008-01-01
1 / ? Luis San Andr?s 2008 1.1 Handout # 1 Modeling of Mechanical (Lumped Parameter) Elements The fundamental components of a mechanical system are: masses or inertias, springs (stiffnesses), and dampers. Lumped elements lead to ordinary... into another form of energy (usually heat). Dampers relate the element force (torque) to a translational (angular) velocity. MEEN 617 Notes: Handout 1 / ? Luis San Andr?s 2008 1.2 Our objective: to determine equivalent system elements as those capable...
Linker, K.L.; Rawlinson, K.S.; Smith, G.
1991-10-01
The Department of Energy's Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program's goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia's Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.
Reduced order Modeling of Heat Exchangers Using High Order Finite Control Volume Models
Gupta, Abhishek
2007-01-01
. In 1998, Tummescheit and Eborn [26] presented the lumped parameter as well as distributed parameter models as a commercially available software package known as Modelica?. Bendapudi [8] compared and validated the moving boundary as well as finite...
Real-time Volumetric Deformable Models for Surgery Simulation using
Real-time Volumetric Deformable Models for Surgery Simulation using Finite Elements volumetric Finite Element models to surgery simulation. In particular it presents three new approaches: Virtual Surgery, Real-Time Deformation, Solid Volumetric Deformable Mod- els, Virtual Reality, Finite
A MIXED FINITE ELEMENT--FINITE VOLUME FORMULATION OF THE BLACKOIL MODEL #
Bergamaschi, Luca
, Italy (marco@ian.pv.cnr.it). Current address: IANCNR, via Abbiategrasso 209, 27100 Pavia, Italy. 970 formulation adopted b
2-D discrete element modeling of unconsolidated sandstones
Franquet Barbara, Javier Alejandro
2001-01-01
In this work unconsolidated sands saturated with heavy oil were modeled using a discrete element numerical model, (DEM). The DEM code was built in Mathematica ? programming language. The strain-stress behavior of biaxial ...
Finite-Volume Spectra of the Lee-Yang Model
Zoltan Bajnok; Omar el Deeb; Paul A. Pearce
2014-12-29
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.
Superconvergence of finite element approximations by a computer-based approach
Gangaraj, Srihari Kumar
1994-01-01
%-SUPERCONVERGENCE . . 5. 1 Preliminaries . . 5. 2 The method of freezing the periodicity 5. 3 Numerical studies of g%-superconvergence . 5. 4 Summary 74 74 79 84 192 CHAPTER VI SUMMARY OF CONCLUSIONS . 6. 1 Conclusions based on this study 6. 2 Directions... shown i? (. I) u it I& tl a?shin? cl& n&cn(s: (&I) The mesh- patch of 1?qu &drat i?l& ln& n(s sh&&n? i? (I&) (vith j la?slllon clem&&nts. 66 73 Figure Figure Figurc Figure Figure 5. 2. Method ol' I& ppzi?g thc pcl'lo&licijy: (a) A finit& elr?1...
Nonconforming finite element methods for the simulation of waves in viscoelastic solids
Sheen, Dongwoo
a , Juan E. Santos b , Dongwoo Sheen c,* a School of Civil, Urban, and Geosystem Engineering, Seoul of waves in two- and three-dimensional bounded viscoelastic media is described in the space frequency element methods are employed for the spatial discretization. Optimal error estimate in a broken energy
Mixed-mode fracture of orthotropic functionally graded materials using finite elements and the
Paulino, Glaucio H.
coordinates, which are integrated into the element stiffness matrix using the isoparametric concept graded materials (FGMs) are special composites in which the volume fraction of constituent materials vary functionally graded ceramic/metal coatings have also been investigated under mechanical and thermal loads using
Blacker, Teddy D. (12205 Kashmir, N.E., Albuquerque, NM 87111)
1994-01-01
An automatic quadrilateral surface discretization method and apparatus is provided for automatically discretizing a geometric region without decomposing the region. The automated quadrilateral surface discretization method and apparatus automatically generates a mesh of all quadrilateral elements which is particularly useful in finite element analysis. The generated mesh of all quadrilateral elements is boundary sensitive, orientation insensitive and has few irregular nodes on the boundary. A permanent boundary of the geometric region is input and rows are iteratively layered toward the interior of the geometric region. Also, an exterior permanent boundary and an interior permanent boundary for a geometric region may be input and the rows are iteratively layered inward from the exterior boundary in a first counter clockwise direction while the rows are iteratively layered from the interior permanent boundary toward the exterior of the region in a second clockwise direction. As a result, a high quality mesh for an arbitrary geometry may be generated with a technique that is robust and fast for complex geometric regions and extreme mesh gradations.
Hilbert, L.B. Jr. [Univ. of California, Berkeley, CA (United States); Fredrich, J.T. [Sandia National Labs., Albuquerque, NM (United States); Bruno, M.S. [Terralog Technologies USA, Inc., Arcadia, CA (United States); Deitrick, G.L.; Rouffignac, E.P. de [Shell Exploration and Production Co., Houston, TX (United States)
1996-05-01
In this paper the authors present the results of a coupled nonlinear finite element geomechanics model for reservoir compaction and well-to-well interactions for the high-porosity, low strength diatomite reservoirs of the Belridge field near Bakersfield, California. They show that well damage and failures can occur under the action of two distinct mechanisms: shear deformations induced by pore compaction, and subsidence, and shear deformations due to well-to-well interactions during production or water injection. They show such casting damage or failure can be localized to weak layers that slide or slip under shear due to subsidence. The magnitude of shear displacements and surface subsidence agree with field observations.
A study of arbitrary rotations of shells of revolution by the finite element method
Rosenbaum, James Byron
1974-01-01
were reduced to eiskf3, ez3kz~, and the squares and products of the two. This contributed rotation effects to the nonlinear strain energy which previously had not been taken into account. As a computational time saver, the partial derivatives... II-1 III-1 IV-1 Geometry of Shell of Revolution Segment. . Coordinization of Shell Element. . Comparison of SNASOR III with New SNASOR III for a Shallow Shell of X = 6. Page 14 26 31 IV-2 Buckling Analysis of Higher Order Strain Energy...
Linker, K.L.; Rawlinson, K.S.; Smith, G.
1991-10-01
The Department of Energy`s Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program`s goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia`s Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.
Hoffman, E.L.; Ammerman, D.J.
1995-04-01
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.
Kondagunta, Veeraraghava Gopal
1993-01-01
and continuity[7]. The model is still two-dimensional and the actual three-dimension- al cross-sectional shape of the fiber bundles was not considered. The fiber undulation model could analyze the knee behavior in plain-weave composites. Ishikawa and Chou [7... is discussed. 23 III. 2 Micromechanics model for calculating fiber tow properties One of the most basic problems in the analysis of the behavior of composite materials is the prediction of effective or average macroscopic properties in terms...
Evaluation of new techniques for two dimensional finite element analysis of woven composites
Gundapaneni, Sitaram Chowdary
1992-01-01
and Harris (1989) proposed a mathematical model for predicting the effective Young's moduli of a laminate with wavy patterns in the main load-carrying layers. Experimental results obtained fmm cor- rugated aluminium specimens and aluminium/epoxy specimens...
PARALLEL FINITE ELEMENT COMPUTATION OF 3D INCOMPRESSIBLE FLOWS ON MPPs
Tezduyar, Tayfun E.
vortex shedding pat- terns are observed. Comparisons are made between computations on a semi-stuctured structure utilized in either model are very different compared to traditional scalaror vector design
Determination of bypass currents in bipolar plate cells using finite elements
Holmes, Joseph Wayne
1984-01-01
. This is usually a valid assumption at very low current densities. Any or all of these boundary conditions can be used in a single problem to mathematically model the physical reality of the system. Since each type of boundary condition imposes certain... collocation to solve a current distribution problem. Their system was a parallel plate cell. The model accounted for geometry, mass transfer effects, and nonlinear electrode kinetics. One of the most commonly used techniques in solution of current...
Madabhushi, S. S. C.; Madabhushi, S. P. G.
2014-10-29
, R., Yang, D. and Naesgaard, E. (2003). Centrifuge modeling for seismic retrofit design of an immersed tube tunnel. Journal of Physical Modelling of Geotechnics 3, No. 2, 23-32. [8] Chou, J.C., Kutter, B.L., Travasarou, T. and Chacko, J.M. (2011... during a major earthquake. Seismic behavior of tunnels and other underground structures can be studied using numerical analyses or physical testing. Cilingir and Madabhushi [1,2,3] investigated the seismic response of square tunnels using both dynamic...
A TRACE FINITE ELEMENT METHOD FOR A CLASS OF COUPLED BULK-INTERFACE TRANSPORT PROBLEMS
Olshanskii, Maxim A.
, MAXIM A. OLSHANSKII, AND ARNOLD REUSKENÂ§ Abstract. In this paper we study a system of advection of coupled partial differential equations arise in, for example, the modeling of transport and diffusion phenomena related to soluble surfactants in two-phase incom- pressible flows we refer to the literature, e
Finite Elements for the Reissner-Mindlin Plate Richard S. Falk
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 1 Introduction In this paper, we consider the approximation of the equations of linear elas. The compliance tensor A is given by A = (1 + )/E - tr()/E, with E > 0 Young's modulus, [0, 1/2) Poisson to stretching and bending of the plate. The most common plate stretch- ing models are variants of the equations
Finite Volume Element Approximations of Nonlocal Reactive Flows in Porous Media
Ewing, Richard E.
, Raytcho Lazarov Institute for Scienti#12;c Computation Texas A&M University 612 Blocker Building College. This model is very important in the transport of reactive and passive contaminates in aquifers, an area point of view, the evolution of either a passive or reactive chemical within a velocity #12;eld
Finite Element Based Micromechanical Analysis of Precipitated NiTi Shape Memory Alloys
Cox, Austin Edward
2015-07-22
into the material and its thermomechanical response than ever before. The most widely modeled and produced SMA class in industry today is one which hosts Ni as a core component of its composition, and usually takes the form of NiTi. When these SMA materials are heat...
Fairag, Faisal
and energy related applications (global change, mixing of fuel and oxidizer in engines and drag reduction), aerodynamics (maneuvering flight of jet aircraft) and biophysical applications (blood flow in the heart equations considered here are identical to Smagorinsky model [21]. Thus, from a practical engineering point
Mathur, Anuj
1994-01-01
In this work we study the pollution-error in the h-version of the finite element method and its effect on the local quality of a-posteriori error estimators. We show that the pollution-effect in an interior subdomain depends on the relationship...
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
Rumpf, Martin
15th Workshop on the Finite Element Method in Biomedical Engineering, Biomechanics and Related A microstructured material of special biomechanical interest is human trabecular bone which is mainly located.rumpf,ole.schwen}@ins.uni-bonn.de Institute of Orthopaedic Research and Biomechanics, University of Ulm {hans
Finite-range model potentials for resonant interactions
Bimalendu Deb
2015-12-04
We show that it is possible to model two-body resonant interactions at low energy with a class of finite-range potentials based on the methods of Jost and Kohn. These potentials are expressed in terms of the effective range $r_0$ and the $s$-wave scattering length $a_s$. We derive continuum solutions of these potentials. By writing $V_{\\pm}(r) = V_{0}(r) + V_{\\pm}^{\\epsilon}(r)$, where the sign +(-) refers to positive(negative) scattering length, $ V_{0}(r)$ is of the form of P\\"{o}schl-Teller potential and $V_{\\pm}^{\\epsilon}$ is expressed as a power series of the small parameter $\\epsilon = (\\sqrt{1 - 2 r_0/a_s})^{-1} - 1 $ when $a_s$ is large, we derive Green function of $V_{0}(r)$. Using the Green function, solutions of $V_{\\pm}(r)$ for $|a_s| >\\!> r_0$ can be obtained numerically by treating $V_{\\pm}^{\\epsilon}(r)$as a perturbation. We describe the threshold behavior of scattering phase shift for $V_{0}(r)$. This study may be important for developing a better understanding of physics of strongly interacting ultracold atomic gases with tunable interactions.
Tezaur, I. K. [Sandia National Laboratories; Perego, M. [Sandia National Laboratories; Salinger, A. G. [Sandia National Laboratories; Tuminaro, R. S. [Sandia National Laboratories; Price, S. F. [Los Alamos National Laboratory
2015-01-01
This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, along with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Tezaur, I. K.; Perego, M.; Salinger, A. G.; Tuminaro, R. S.; Price, S. F.
2015-04-27
This paper describes a new parallel, scalable and robust finite element based solver for the first-order Stokes momentum balance equations for ice flow. The solver, known as Albany/FELIX, is constructed using the component-based approach to building application codes, in which mature, modular libraries developed as a part of the Trilinos project are combined using abstract interfaces and template-based generic programming, resulting in a final code with access to dozens of algorithmic and advanced analysis capabilities. Following an overview of the relevant partial differential equations and boundary conditions, the numerical methods chosen to discretize the ice flow equations are described, alongmore »with their implementation. The results of several verification studies of the model accuracy are presented using (1) new test cases for simplified two-dimensional (2-D) versions of the governing equations derived using the method of manufactured solutions, and (2) canonical ice sheet modeling benchmarks. Model accuracy and convergence with respect to mesh resolution are then studied on problems involving a realistic Greenland ice sheet geometry discretized using hexahedral and tetrahedral meshes. Also explored as a part of this study is the effect of vertical mesh resolution on the solution accuracy and solver performance. The robustness and scalability of our solver on these problems is demonstrated. Lastly, we show that good scalability can be achieved by preconditioning the iterative linear solver using a new algebraic multilevel preconditioner, constructed based on the idea of semi-coarsening.« less
Blunt-crack band propagation in finite-element analysis for concrete structures. [LMFBR
Pfeiffer, P.A.; Bazant, Z.P.; Marchertas, A.H.
1983-01-01
The knowledge of concrete fracture is needed in nuclear reactor safety. The question of safety arises from the potential of concrete to crack under thermal loading. It has been postulated that structural concrete could be exposed to very high temperature, which may result from hot reactor coolant or even core debris coming in direct contact with the concrete. The utilization of the blunt crack approach for simulating concrete cracking in a general-purpose code is explored. The difficulties encountered in establishing the proper direction of crack propagation in an arbitrary discretization are described. Crack propagation is considered within the context of two types of solution techniques: (1) implicit solution of the static crack advance, and (2) explicit time integration using a dynamic relaxation technique to simulate the static crack advance. Also, in both solution techniques an elastic model is used to characterize the concrete.
Discrete-element model for the interaction between ocean waves and sea ice
Xu, Zhijie; Tartakovsky, Alexandre M.; Pan, Wenxiao
2012-01-05
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.
Finite element analysis of the I-40 bridge over the Rio Grande
Farrar, C.R.; Duffey, T.A.; Goldman, P.A.; Jauregui, D.V.; Vigil, J.S.
1996-01-01
In the 1960s and 1970s numerous bridges were built in the US with a design similar to those on Interstate 40 (I-40) over the Rio Grande in Albuquerque, New Mexico. The Federal Highway Administration (FHWA) and the National Science Foundation (NSF) have provided funds to New Mexico State University (NMSU) through the New Mexico State Highway and Transportation Department (NMSH and TD) and The Alliance For Transportation Research (ATR) for evaluation and testing of the existing fracture-critical bridges over the Rio Grande. Because the I-40 Bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce damage into the structure in order to test various damage identification methods and to observe the changes in load paths through the structure caused by the cracking. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. A previous report (LA-12767-MS) summarizes the results of the experimental modal analyses. This report summarizes the numerical analyses of the bridges and compares the results of these analyses to the experimental results.
Cheng, C.Z.
1988-12-01
A nonvariational ideal MHD stability code (NOVA) has been developed. In a general flux coordinate (/psi/, theta, /zeta/) system with an arbitrary Jacobian, the NOVA code employs Fourier expansions in the generalized poloidal angle theta and generalized toroidal angle /zeta/ directions, and cubic-B spline finite elements in the radial /psi/ direction. Extensive comparisons with these variational ideal MHD codes show that the NOVA code converges faster and gives more accurate results. An extended version of NOVA is developed to integrate non-Hermitian eigenmode equations due to energetic particles. The set of non-Hermitian integro-differential eigenmode equations is numerically solved by the NOVA-K code. We have studied the problems of the stabilization of ideal MHD internal kink modes by hot particle pressure and the excitation of ''fishbone'' internal kink modes by resonating with the energetic particle magnetic drift frequency. Comparisons with analytical solutions show that the values of the critical ..beta../sub h/ from the analytical theory can be an order of magnitude different from those computed by the NOVA-K code. 24 refs., 11 figs., 1 tab.
Quinones, Armando (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2006-06-01
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.
Torres-Verdín, Carlos
hp-Adaptive Multiphysics Finite Element Simulation of LWD Borehole Sonic Waveforms Pawel J-physics, finite-element method to simulate LWD borehole acoustic waveforms in the presence of the tool. The method truncation of the spatial domain. Examples of appli- cation are shown for the simulation of LWD sonic
Calisch, Samuel Eli
2014-01-01
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 ...
Williams, P.T.
1993-09-01
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.
Momentum dependence of the spectral functions in the O(4) linear sigma model at finite temperature
Yoshimasa Hidaka; Osamu Morimatsu; Tetsuo Nishikawa
2003-04-09
The spatial momentum dependence of the spectral function for pi and sigma at finite temperature is studied by employing the O(4) linear sigma model and adopting a resummation technique called optimized perturbation theory (OPT).
Reeder, D. Benjamin (Davis Benjamin), 1966-
2002-01-01
This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic ...
Gieras, J.F.; Wing, M. [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Electrical Engineering] [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Electrical Engineering; Santini, E. [Univ. of Rome (Italy). Dept. of Electrical Engineering] [Univ. of Rome (Italy). Dept. of Electrical Engineering
1998-09-01
The synchronous reactances of permanent magnet (PM) motors have been determined using: (1) analytical method, i.e., form factors of the stator field (armature reaction factors), (2) finite element method (FEM), and (3) experimental tests on a special machine set. The analytical method is widely used in calculations of synchronous reactances of salient pole synchronous machines with electromagnetic excitation. Rotors of PM synchronous machines have more complicated structures, hence it is more difficult to predict accurately the magnetic field distribution in their airgaps in order to find the form factors of the stator field. Numerical methods of field analysis can easily solve this problem. The FEM can predict both the synchronous and mutual (armature reaction) reactances in the d and q axes. The leakage reactance can then be evaluated as a difference between synchronous and mutual reactances. As an example, a small, three-phase, four-pole motor with SmCo surface mounted PM`s (three parallel magnets per pole), and mild-steel pole shoes has been investigated. Such a complicated rotor structure has been intentionally designed in order to be able to compare the advantages and disadvantages of the analytical method and the FEM. In the FEM, the reactances have been calculated using both the flux linkage and current/energy perturbation method. Synchronous reactances as functions of the stator current and load angle obtained analytically from the FEM modeling and from measurements have been compared.
Biffle, J.H.
1993-02-01
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.
Robert M. Parrish; Edward G. Hohenstein; Nicolas F. Schunck; C. David Sherrill; Todd J. Martinez
2013-09-05
Configuration-space matrix elements of N-body potentials arise naturally and ubiquitously in the Ritz-Galerkin solution of many-body quantum problems. For the common specialization of local, finite-range potentials, we develop the eXact Tensor HyperContraction (X-THC) method, which provides a quantized renormalization of the coordinate-space form of the N-body potential, allowing for a highly separable tensor factorization of the configuration-space matrix elements. This representation allows for substantial computational savings in chemical, atomic, and nuclear physics simulations, particularly with respect to difficult "exchange-like" contractions.
Formal computational models and non-standard finiteness
Ayala-RincÃ³n, Mauricio
(f) #12;Finiteness in Computation ^ without NNO T : Pos - f : P(Q Ã? Pos Ã? Tfin) - P(Q Ã? Posfin Ã? Q), such that Tfin = {h/fin({p Pos : h(p) = b})} X = P(Q Ã? Pos Ã? Tfin), St(X) = {S X : f(S) S} i : St(X) P(X) has = { x , y /Pos , yT > ^ Pos , xT > and final(q)} #12;Finitenes
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
Nonparametric Finite Multivariate
Hunter, David
Nonparametric Finite Multivariate Mixture Models with Applications Xiaotian Zhu Introduction-Minimization #12;Nonparametric Finite Multivariate Mixture Models with Applications Xiaotian Zhu Introduction-Minimization #12;Nonparametric Finite Multivariate Mixture Models with Applications Xiaotian Zhu Introduction
HIGH-ORDER FINITE VOLUME SCHEMES FOR LAYERED ATMOSPHERIC MODELS
of use of layered models are: air pollution models (see for example the early study in [1]), moisture
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
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)
2010-09-30
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.
Isothermal model of ICF burn with finite alpha range treatment
Galloway, Conner Daniel (Conner Daniel Cross)
2009-01-01
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
2005-11-30
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.
Nonlinear finite-Larmor-radius effects in reduced fluid models
Brizard, A. J. [Department of Chemistry and Physics, Saint Michael's College, Colchester, Vermont 05439 (United States); Denton, R. E.; Rogers, B. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Lotko, W. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States)
2008-08-15
The polarization magnetization effects associated with the dynamical reduction leading to the nonlinear gyrokinetic Vlasov-Maxwell equations are shown to introduce nonlinear finite-Larmor-radius (FLR) effects into a set of nonlinear reduced-fluid equations previously derived by the Lagrangian variational method [A. J. Brizard, Phys. Plasmas 12, 092302 (2005)]. These intrinsically nonlinear FLR effects, which are associated with the transformation from guiding-center phase-space dynamics to gyrocenter phase-space dynamics, are different from the standard FLR corrections associated with the transformation from particle to guiding-center phase-space dynamics. We also present the linear dispersion relation results from a nonlinear simulation code using these reduced-fluid equations. The simulation results (in both straight dipole geometries) demonstrate that the equations describe the coupled dynamics of Alfven sound waves and that the total simulation energy is conserved.
Zero finite-temperature charge stiffness within the half-filled 1D Hubbard model
Carmelo, J.M.P., E-mail: carmelo@fisica.uminho.pt [Center and Department of Physics, University of Minho, Campus Gualtar, P-4710-057 Braga (Portugal) [Center and Department of Physics, University of Minho, Campus Gualtar, P-4710-057 Braga (Portugal); Beijing Computational Science Research Center, Beijing 100084 (China); Institut für Theoretische Physik III, Universität Stuttgart, D-70550 Stuttgart (Germany); Gu, Shi-Jian [Beijing Computational Science Research Center, Beijing 100084 (China) [Beijing Computational Science Research Center, Beijing 100084 (China); Department of Physics and ITP, Chinese University of Hong Kong, Hong Kong (China); Sacramento, P.D. [CFIF, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal) [CFIF, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Beijing Computational Science Research Center, Beijing 100084 (China)
2013-12-15
Even though the one-dimensional (1D) Hubbard model is solvable by the Bethe ansatz, at half-filling its finite-temperature T>0 transport properties remain poorly understood. In this paper we combine that solution with symmetry to show that within that prominent T=0 1D insulator the charge stiffness D(T) vanishes for T>0 and finite values of the on-site repulsion U in the thermodynamic limit. This result is exact and clarifies a long-standing open problem. It rules out that at half-filling the model is an ideal conductor in the thermodynamic limit. Whether at finite T and U>0 it is an ideal insulator or a normal resistor remains an open question. That at half-filling the charge stiffness is finite at U=0 and vanishes for U>0 is found to result from a general transition from a conductor to an insulator or resistor occurring at U=U{sub c}=0 for all finite temperatures T>0. (At T=0 such a transition is the quantum metal to Mott–Hubbard-insulator transition.) The interplay of the ?-spin SU(2) symmetry with the hidden U(1) symmetry beyond SO(4) is found to play a central role in the unusual finite-temperature charge transport properties of the 1D half-filled Hubbard model. -- Highlights: •The charge stiffness of the half-filled 1D Hubbard model is evaluated. •Its value is controlled by the model symmetry operator algebras. •We find that there is no charge ballistic transport at finite temperatures T>0. •The hidden U(1) symmetry controls the U=0 phase transition for T>0.
Chu, Howard
2015-01-01
accurate location and material properties of the bone andthe dissimilar material properties and capturing the localfinite elements. The material properties of the craniofacial
Nellie Rajarova,
2010-07-14
was obtained by substituting equation (2.14) in the weak form (2.9). 0 1 ???? ? ??? ?? ??? ? ? ?? ? ? ? ??? ? ??? ? ? ? ? ???? ? ? ??? ? ? ? ? ? ??? ? ??? ? dsqfud x d ycyayxax eee iij N j ji j yy ij xx i ???????? (2.15) 16 In matrix form equation (2..., 19 ? ? )33.2(21 232221 d x d yRRRI ee ?? ??? where, )34.2(,, 321 fcuyvxvRavyuRavxuR hhyhx yy hyh xx hxh ?? ?????????????? The functional associated with equations (2.33) is ? ? )35.2(, 222, d x d yfcuyvxvavyuavxuvvuI e hhyhx yy hyh xx...
Richgels, M A; Biffle, J H
1980-09-01
ALGEBRA is a program that allows the user to process output data from finite-element analysis codes before they are sent to plotting routines. These data take the form of variable values (stress, strain, and velocity components, etc.) on a tape that is both the output tape from the analyses code and the input tape to ALGEBRA. The ALGEBRA code evaluates functions of these data and writes the function values on an output tape that can be used as input to plotting routines. Convenient input format and error detection capabilities aid the user in providing ALGEBRA with the functions to be evaluated. 1 figure.
Alfven-wave particle interaction in finite-dimensional self-consistent field model
Padhye, N.; Horton, W.
1998-10-09
A low-dimensional Hamiltonian model is derived for the acceleration of ions in finite amplitude Alfven waves in a finite pressure plasma sheet. The reduced low-dimensional wave-particle Hamiltonian is useful for describing the reaction of the accelerated ions on the wave amplitudes and phases through the self-consistent fields within the envelope approximation. As an example, the authors show for a single Alfven wave in the central plasma sheet of the Earth`s geotail, modeled by the linear pinch geometry called the Harris sheet, the time variation of the wave amplitude during the acceleration of fast protons.
Application of Finite Mixture Models for Vehicle Crash Data Analysis
Park, Byung Jung
2010-07-14
Developing sound or reliable statistical models for analyzing vehicle crashes is very important in highway safety studies. A difficulty arises when crash data exhibit overdispersion. Over-dispersion caused by unobserved ...
Discrete Element Crowd Model for Pedestrian Evacuation Through an Exit
Lin, Peng; Lo, Siuming
2015-01-01
A series of accidents caused by crowd within the last decades evoked a lot of scientific interest in modeling the movement of pedestrian crowds. Based on discrete element method, a granular dynamic model, in which human body is simplified as self-driven sphere, is proposed to simulate the characteristics of crowd flow through an exit. In this model, the repulsive force among people is considered to have an anisotropic feature, and the physical contact force due to body deformation is quantified by the Hertz contact model. The movement of human body is simulated by applying the second Newton's law. The crowd flow through an exit at different desired velocities is studied and simulation results indicated that crowd flow exhibits three distinct states, i.e., smooth state, transition state and phase separation state. In the simulation, clogging phenomenon occurs more easily when the velocity of desired is high and the exit may as a result be totally blocked at a desired velocity of 1.6m/s or above, leading to fas...
Meson properties in a nonlocal SU(3) chiral quark model at finite temperature
Contrera, G. A.; Gomez Dumm, D.; Scoccola, N. N.
2010-11-12
Finite temperature meson properties are studied in the context of a nonlocal SU(3) quark model which includes flavor mixing and the coupling of quarks to the Polyakov loop (PL). We analyze the behavior of scalar and pseudoscalar meson masses and mixing angles, as well as quark-meson couplings and pseudoscalar meson decay constants.
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 of innovative Structural Health Monitoring (SHM) methods and systems. Of particular importance is the design European Workshop on Structural Health Monitoring July 8-11, 2014. La Cité, Nantes, France Copyright
Finite source modelling of magmatic unrest in Socorro, New Mexico, and Long Valley, California
Fialko, Yuri
Finite source modelling of magmatic unrest in Socorro, New Mexico, and Long Valley, California Yuri associated with currently active crustal magma bodies in Socorro, New Mexico, and Long Valley, California induced by magma migration are also important for forecasting local volcanic and seismic hazards. A prime
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
Discrete-element modeling of particulate aerosol flows
Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu
2009-03-20
A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.
M. Abu-Shady
2014-03-13
A baryonic chemical potential is included in the linear sigma model at finite temperature. The effective mesonic potential is numerically calculated using the midpoint technique. The meson masses are investigated as functions of the temperature at fixed value of baryonic chemical potential. The pressure and energy density are investigated as functions of temperature at fixed value of chemical potential. The obtained results are in good agreement in comparison with other techniques. We conclude that the calculated effective potential successfully predicts the meson properties and thermodynamic properties at finite baryonic chemical potential.
Finite-temperature spectral function of the vector mesons in an AdS/QCD model
Mitsutoshi Fujita; Kenji Fukushima; Tatsuhiro Misumi; Masaki Murata
2009-03-28
We use the soft-wall AdS/QCD model to investigate the finite-temperature effects on the spectral function in the vector channel. The dissociation of the vector meson tower onto the AdS black hole leads to the in-medium mass shift and the width broadening in a way similar to the lattice QCD results for the heavy quarkonium at finite temperature. We also show the momentum dependence of the spectral function and find it consistent with screening in a hot wind.
Structure of finite-RSB asymptotic Gibbs measures in the diluted spin glass models
Dmitry Panchenko
2015-02-25
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.
Winding Transitions at Finite Energy and Temperature: An O(3) Model
Salman Habib; Emil Mottola; Peter Tinyakov
1996-08-14
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.
Approved Module Information for ME3070, 2014/5 Module Title/Name: Solid Mechanics and Finite Element
Neirotti, Juan Pablo
Basic Ansys Exercise Coursework Individual Assignment 28/Nov/2014 Yes 35% Details Intermediate Ansys Element Analysis Module Code: ME3070 School: Engineering and Applied Science Module Type: Standard Module: Level 6 (Bachelors) Programmes in which available: BEng Design Engineering. BEng/MEng Electromechanical
Finite element methods for 3D eddy current prob-lems in bounded domains subject to realistic
Rodríguez, Rodolfo
devices such us electrical machines, induction heating systems, transformers, waveguides, microwaves, etc formulations based on the magnetic or the electric field, approximated by means of edge elements. The most electric furnaces are discussed and numerical results are given. 1 INTRODUCTION Numerical simulation plays
Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature
Gomez Dumm, D.; Contrera, G. A.
2012-06-15
We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.
CP(N-1) model on finite interval in the large N limit
A. Milekhin
2012-07-02
The CP(N-1) \\sigma\\ model on finite interval of length R with Dirichlet boundary conditions is analysed in the 1/N expansion. The theory has two phases, separated by a phase transition at R ~ 1/\\Lambda, \\Lambda\\ is dynamical scale of the CP(N-1) model. The vacuum energy dependence of R, and especially Casimir-type scaling 1/R, is discussed.
Finite temperature behaviour of the ISS-uplifted KKLT model
Chloe Papineau
2008-05-05
We study the static phase structure of the ISS-KKLT model for moduli stabilisation and uplifting to a zero cosmological constant. Since the supersymmetry breaking sector and the moduli sector are only gravitationally coupled, we expect negligible quantum effects of the modulus upon the ISS sector, and the other way around. Under this assumption, we show that the ISS fields end up in the metastable vacua. The reason is not only that it is thermally favoured (second order phase transition) compared to the phase transition towards the supersymmetric vacua, but rather that the metastable vacua form before the supersymmetric ones. This nice feature is exclusively due to the presence of the KKLT sector. We also show that supergravity effects are negligible around the origin of the field space. Finally, we turn to the modulus sector and show that there is no destabilisation effect coming from the ISS sector.
The finite and large-N behaviors of independent-value matrix models
Ben Geloun, Joseph; Klauder, John R.
2014-03-15
We investigate the finite and large N behaviors of independent-value O(N)-invariant matrix models. These are models defined with matrix-type fields and with no gradient term in their action. They are generically nonrenormalizable but can be handled by nonperturbative techniques. We find that the functional integral of any O(N) matrix trace invariant may be expressed in terms of an O(N)-invariant measure. Based on this result, we prove that, in the limit that all interaction coupling constants go to zero, any interacting theory is continuously connected to a pseudo-free theory. This theory differs radically from the familiar free theory consisting in putting the coupling constants to zero in the initial action. The proof is given for generic, finite-size matrix models, whereas, in the limiting case N ? ?, we succeed in showing this behavior for restricted types of actions using a particular scaling of the parameters.
A new Cement to Glue non-conforming Grids with Robin interface conditions: the finite element case
Japhet, Caroline; Nataf, Frédéric
2007-01-01
We design and analyze a new non-conforming domain decomposition method based on Schwarz type approaches that allows for the use of Robin interface conditions on non-conforming grids. The method is proven to be well posed, and the iterative solver to converge. The error analysis is performed in 2D piecewise polynomials of low and high order and extended in 3D for $P_1$ elements. Numerical results in 2D illustrate the new method.
Generating meshes for finite-difference analysis using a solid modeler
Laguna, G.W.; White, W.T.; Cabral, B.K.
1987-09-01
One tool used by the Engineering Research Division of LLNL to help analyze the behavior of electronic systems in hostile environments is 3D finite-difference time-domain (FDTD) computation. FDTD codes solve Maxwell's equations,the differential equations of electromagnetism, on a uniform lattice of points. It is this uniform lattice, or ''mesh,'' that distinguishes finite-difference codes from other codes. The simple mesh makes FDTD codes computationally more efficient than other codes, which enables them to run larger problems and to run faster (up to thirty times faster than finite-element codes, for example). Therefore, within the Engineering Department at LLNL, Electronics Engineering (EE) has initiated a project to develop a mesh generator that will provide meshes suitable for FDTD analysis. This report describes the results of the first year of EE's FDTD Mesh Generation Project. During this year a preliminary version of an automated mesh generator was built and used to create a mesh of an object of interest to the High-Power Microwave Program, namely an electrically detonatable land mine. The code was verified by meshing basic solids such as spheres and cylinders. Because of the design of the code, there is no software limitation to the size of meshes that can be accommodated. The algorithm with a mesh space of approximately 500,000 cells has been demonstrated. The mesh generator can detect certain objects with walls that are thinner than the width of a cell. The code has internal graphics for viewing objects as they appear prior to being converted to a finite-difference representation. Additionally, via data files, the code is coupled to two external graphics packages for visually checking the meshes, namely TAURUS on the Cray and a new code, IMAGE, on the Silicon Graphics IRIS workstation.
Fornberg, Bengt
) Email: Amik.St-Cyr@shell.com #12;2 ABSTRACT Seismic exploration is the primary tool for finding1 Seismic modeling with radial basis function-generated finite differences (RBF-FD) (Seismic of Colorado-Boulder) Email: Fornberg@colorado.edu Amik St-Cyr (Shell International Exploration and Production
Hoffman, E.L.; Ammerman, D.J.
1995-04-01
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. Four axial impact tests were performed on 4 in-diameter, 8 in-long, 304 L stainless steel cylinders with a 3/16 in wall thickness. The cylinders were struck by a 597 lb mass with an impact velocity ranging from 42.2 to 45.1 ft/sec. During the impact event, a buckle formed at each end of the cylinder, and one of the two buckles became unstable and collapsed. The instability occurred at the top of the cylinder in three tests and at the bottom in one test. Numerical simulations of the test were performed using the following codes and element types: PRONTO2D with axisymmetric four-node quadrilaterals; PRONTO3D with both four-node shells and eight-node hexahedrons; and ABAQUS/Explicit with axisymmetric two-node shells and four-node quadrilaterals, and 3D four-node shells and eight-node hexahedrons. All of the calculations are compared to the tests with respect to deformed shape and impact load history. As in the tests, the location of the instability is not consistent in all of the calculations. However, the calculations show good agreement with impact load measurements with the exception of an initial load spike which is proven to be the dynamic response of the load cell to the impact. Finally, the PRONIT02D calculation is compared to the tests with respect to strain and acceleration histories. Accelerometer data exhibited good qualitative agreement with the calculations. The strain comparisons show that measurements are very sensitive to gage placement.
Navon, Michael
for the tropical Pacific Ocean reduced gravity model Zhendong Luo a , Jiang Zhu b , Ruiwen Wang b , I.M. Navon c Available online 8 May 2007 Abstract In this paper, the tropical Pacific Ocean reduced gravity model and the insufficient knowledge of airsea exchange processes. The tropical Pacific Ocean reduced gravity model
Monte Carlo study of Lefschetz thimble structure in one-dimensional Thirring model at finite density
Fujii, Hirotsugu; Kikukawa, Yoshio
2015-01-01
We consider the one-dimensional massive Thirring model formulated on the lattice with staggered fermions and an auxiliary compact vector (link) field, which is exactly solvable and shows a phase transition with increasing the chemical potential of fermion number: the crossover at a finite temperature and the first order transition at zero temperature. We complexify its path-integration on Lefschetz thimbles and examine its phase transition by hybrid Monte Carlo simulations on the single dominant thimble. We observe a discrepancy between the numerical and exact results in the crossover region for small inverse coupling $\\beta$ and/or large lattice size $L$, while they are in good agreement at the lower and higher density regions. We also observe that the discrepancy persists in the continuum limit keeping the temperature finite and it becomes more significant toward the low-temperature limit. This numerical result is consistent with our analytical study of the model's thimble structure. And these results imply...
2D numerical simulation of the MEP energy-transport model with a finite difference scheme
Romano, V. . E-mail: romano@dmi.unict.it
2007-02-10
A finite difference scheme of Scharfetter-Gummel type is used to simulate a consistent energy-transport model for electron transport in semiconductors devices, free of any fitting parameters, formulated on the basis of the maximum entropy principle. Simulations of silicon n{sup +}-n-n{sup +} diodes, 2D-MESFET and 2D-MOSFET and comparisons with the results obtained by a direct simulation of the Boltzmann transport equation and with other energy-transport models, known in the literature, show the validity of the model and the robustness of the numerical scheme.
Renormalization Group Analysis of Finite-Size Scaling in the $?^4_4$ Model
R. Kenna; C. B. Lang
1992-10-08
A finite-size scaling theory for the $\\phi^4_4$ model is derived using renormalization group methods. Particular attention is paid to the partition function zeroes, in terms of which all thermodynamic observables can be expressed. While the leading scaling behaviour is identical to that of mean field theory, there exist multiplicative logarithmic corrections too. A non-perturbative test of these formulae in the form of a high precision Monte Carlo analysis reveals good quantitative agreement with the analytical predictions.
Plotkin, Steven S.
Correlated energy landscape model for finite, random heteropolymers Steven S. Plotkin, Jin Wang, Illinois 61801 Received 26 December 1995 In this paper, we study the role of correlations in the energy landscape of a finite random heteropolymer by developing the mapping onto the generalized random energy
Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay
Horoi, Mihai
2013-12-30
Recent progress in the shell model approach to the nuclear matrix elements for the double beta decay process are presented. This includes nuclear matrix elements for competing mechanisms to neutrionless double beta decay, a comparison between closure and non-closure approximation for {sup 48}Ca, and an updated shell model analysis of nuclear matrix elements for the double beta decay of {sup 136}Xe.
Finite temperature spin-dynamics and phase transitions in spin-orbital models
Chen, C.-C.
2010-04-29
We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition, consistent with that of a 2D Ising model, to an orbitally ordered state at a temperature set by short-range magnetic order. At low temperatures the orbital degrees of freedom freeze-out and the model maps onto a quantum Heisenberg model. The onset of orbital excitations causes a rapid scrambling of the spin spectral weight away from coherent spin-waves, which leads to a sharp increase in uniform magnetic susceptibility just below the phase transition, reminiscent of the observed behavior in the Fe-pnictide materials.
Kim, Jongheon
2013-01-01
An- alytical Methods in Geomechanics, 31(2):239–259. DvorkinAnalytical Methods in Geomechanics, 28:609–632. Oliver J,and Analytical Methods in Geomechanics, 2:99–128. Ventura G,
A finite element model of grain boundary sliding for nanostructured metals
Jérusalem, Antoine, 1979-
2004-01-01
Nanocrystalline metals, i.e., polycrystalline metals with grain sizes in the nanometer range, have elicited significant interest recently due to their potential for achieving higher material strength in combination with ...
Quantum Corrected DriftDiffusion Models: Solution Fixed Point Map and Finite Element Approximation
principles and order of convergence) are discussed. Numerical results on realistic nanoscale devices of semiconductor industry makes it un- avoidable to resort to numerical simulation to predict the electric2008). Preprint submitted to Journal of Computational Physics December 6, 2007 #12;vices of the next generation
Finite Element Modeling of Dermally-implanted Enzymatic Microparticle Glucose Sensors
Ali, Saniya
2011-10-21
With the rising prevalence of diabetes, effective means of successful management of blood glucose levels are increasingly important. To improve on the ease of measurements, new technology is being developed to enable less ...
Shahri, Mehdi Abbaszadeh
2006-04-12
Stability????.?????? 25 5.2 Wellbore Stability in Shale???..??????????.. 26 5.3 Various Instability Risk Criteria?.???????.???. 27 5.4 Borehole Stability Analysis?????????????.. 27 CHAPTER VI..., to the manifold methods of mining ore and aggregate materials, to the stability of petroleum wellbores, and including newer applications such as geothermal energy and radioactive waste disposal. 1.1 Importance of Primary Cementing on Cost Avoiding remedial...
Damage Identification of a Composite Beam Using Finite Element Model Updating
Moaveni, Babak; He, Xianfei; Conte, Joel P; De Callafon, Raymond A.
2008-01-01
Shevitz, D. W. (1996), Damage identification in structuresreview of vibration-based damage identification methods, TheM. , & Samman, M. M. (1991), Damage detection from changes
Damage Identification of a Composite Beam Using Finite Element Model Updating
Moaveni, Babak; He, Xianfei; Conte, Joel P; De Callafon, Raymond A.
2008-01-01
A review of structural health monitoring literature: 1996-In recent years, structural health monitoring has receivedvibration based structural health monitoring for large and
Styles, Vanessa
for superconductivity C. M. Elliott, D. Kay #3; and V. Styles Centre for Mathematical Analysis and its Applications long cylindrical superconductor subject to a transverse magnetic #12;eld. We introduce a #12;nite-II superconductors formulated in terms of the current density and the electric #12;eld intensity. The physical
Kim, Jongheon
2013-01-01
in statics and dy- namics,” Computational Mechanics, 40(3):static and locading conditions,” Computer Methods in Applied Mechanics and
Finite element modeling of neotectonics in New Zealand Zhen Liu and Peter Bird
Bird, Peter
Zealand's faults have effective friction of $0.17, comparable to that found in other Pacific Rim regions forearc is an independent plate sliver moving relative to the Pacific and Australian plates to Geographic Region: Pacific Ocean; 3040 Marine Geology and Geophysics: Plate tectonics (8150, 8155, 8157, 8158
A stabilized stochastic finite element second-order projection method for modeling
Zabaras, Nicholas J.
of freedom. Because of the porosity dependence of the pressure gradient term in the governing flow equations-order projection method is presented based on a pressure gradient projection. A two- dimensional stochastic problem occurring in var- ious applications such as fluidized beds, solidification of alloys, geothermal energy
Finite Element Procedures for 2D and 3D Seismoelectric Modeling
... Street, West Lafayette, Indiana, 47907-2067, USA; santos@math.purdue.edu ... x2 is the symmetry axis) and consider a seismic line source in the x2-direction. ...... “Reflection and transmission coefficients in fluid-saturated porous media," J. ...... Q_h u^f - u^f) , \\frac{\\p \\gamma^B}{\\p t})(s) ds\\right| \\label{eq_69}\\\\ &&\\qquad ...
BILAYER PLATES: MODEL REDUCTION, -CONVERGENT FINITE ELEMENT APPROXIMATION AND DISCRETE GRADIENT FLOW
Bonito, Andrea
by the deformation as in the case of the bending of a piece of paper. A related numerical method has been devised for the practical computation of large bilayer bending deformations. Our contributions in this paper are FLOW SÂ¨OREN BARTELS, ANDREA BONITO , AND RICARDO H. NOCHETTO Abstract. The bending of bilayer plates
Lee, Sang Hoon
2012-02-14
Stress and permeability variations around a wellbore and in the reservoir are of much interest in petroleum and geothermal reservoir development. Water injection causes significant changes in pore pressure, temperature, ...
A P 1 \\Gamma P 0 FINITE ELEMENT METHOD FOR A MODEL OF POLYMER CRYSTALLIZATION*
Nochetto, Ricardo H.
-posedness theorem. © 2008 Elsevier Inc. All rights reserved. MSC: 76A10; 35L80; 35A05; 35B45; 35B50; 80A22 Keywords
A Finite Element Model Of Self-Resonating Bimorph Microcantilever For Fast
Office of Scientific and Technical Information (OSTI)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL Small-scaleCoherent Light SourceAConnect
Torres-Verdín, Carlos
with an Iterative Solver for the Simulation of 3D LWD Measurements Acquired in Deviated Wells D. Pardo1 , M. J. Nam1-while-drilling (LWD) instrument operating at 1.75 MHz in a 55-degree deviated well. Numerical results confirm the high. The method is applied to the simulation of LWD measurements in a 55-degree deviated well. 2. MODEL PROBLEM
Comparison of finite-difference and ray-theory seismograms in the elastic SEG/EAGE Salt Model,
Cerveny, Vlastislav
Comparison of finite-difference and ray-theory seismograms in the elastic SEG/EAGE Salt Model, shot-difference seismograms for a selected shot and two receiver configurations com- puted in the elastic SEG/EAGE Salt Model-waves and converted S-waves in the smoothed elastic SEG/EAGE Salt Model are computed. Keywords Elastic velocity model
Modeling fluid flow in deformation bands with stabilized localization...
Office of Scientific and Technical Information (OSTI)
Modeling fluid flow in deformation bands with stabilized localization mixed finite elements. Citation Details In-Document Search Title: Modeling fluid flow in deformation bands...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, Y.; Mahowald, N.; Scanza, R.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J.; Zhuang, G.; Chen, Y.; Cohen, D. D.; et al
2014-12-17
Trace element deposition from desert dust has important impacts on ocean primary productivity. In this study, emission inventories for 8 elements, which are primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si were determined based on a global mineral dataset and a soils dataset. Datasets of elemental fractions were used to drive the desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions was evident on a global scale, particularly for Ca. Simulations of global variations in the Camore »/ Al ratio, which typically ranged from around 0.1 to 5.0 in soil sources, were consistent with observations, suggesting this ratio to be a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different that estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observational elemental aerosol concentration data from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions ranged from 0.7 to 1.6 except for 3.4 and 3.5 for Mg and Mn, respectivly. Using the soil data base improved the correspondence of the spatial hetereogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust associated element fluxes into different ocean basins and ice sheets regions have been estimated, based on the model results. Annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using mineral dataset were 0.28 Tg, 16.89 Gg, 1.32 Tg, 22.84 Gg, 0.068 Tg, and 0.15 Tg to global oceans and ice sheets.« less
Guerin, P.; Baudron, A. M.; Lautard, J. J.
2006-07-01
This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)
Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in 't Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)
2014-03-14
A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.
Walter Arne; Nicole Marheineke; Andreas Meister; Raimund Wegener
2012-07-03
The spinning of slender viscous jets can be described asymptotically by one-dimensional models that consist of systems of partial and ordinary differential equations. Whereas the well-established string models possess only solutions for certain choices of parameters and set-ups, the more sophisticated rod model that can be considered as $\\epsilon$-regularized string is generally applicable. But containing the slenderness ratio $\\epsilon$ explicitely in the equations complicates the numerical treatment. In this paper we present the first instationary simulations of a rod in a rotational spinning process for arbitrary parameter ranges with free and fixed jet end, for which the hitherto investigations longed. So we close an existing gap in literature. The numerics is based on a finite volume approach with mixed central, up- and down-winded differences, the time integration is performed by stiff accurate Radau methods.
GJ McLachlan Given the extensive use of finite mixture models in the clustering of data sets from a
McLachlan, Geoff
data. The authors state that "an obvious problem with the model-based approach is that statisticiansGJ McLachlan Given the extensive use of finite mixture models in the clustering of data sets from of mixed data where perhaps mixture models have not been applied to the same extent as with continuous data
Ken-Ichi Aoki; Hidenari Uoi; Masatoshi Yamada
2015-07-09
We study the Nambu--Jona-Lasinio (NJL) model at finite temperature and finite density in an external magnetic field using the Functional Renormalization Group (FRG). The dependence of the position of UltraViolet Fixed Point (UVFP) of the four-fermi coupling constant on temperature, density and external magnetic field is investigated and we obtain the chiral phase structure. The UVFP at low temperature and finite chemical potential oscillates in small external magnetic field, which can be interpreted as the de-Haas--van-Alfen effect. We also find that the external magnetic field moves the chiral phase boundary towards the symmetric side at low temperature and high density region.
Aoki, Ken-Ichi; Yamada, Masatoshi
2015-01-01
We study the Nambu--Jona-Lasinio (NJL) model at finite temperature and finite density in an external magnetic field using the Functional Renormalization Group (FRG). The dependence of the position of UltraViolet Fixed Point (UVFP) of the four-fermi coupling constant on temperature, density and external magnetic field is investigated and we obtain the chiral phase structure. The UVFP at low temperature and finite chemical potential oscillates in small external magnetic field, which can be interpreted as the de-Haas--van-Alfen effect. We also find that the external magnetic field moves the chiral phase boundary towards the symmetric side at low temperature and high density region.
Ã¥ Risa-R-411 Nonlinear Finite Element Analysis of Concrete Structures Niels Saabye Ottosen RisÃ¸ | other IAEA P. 0. Box 100 A-1400, Vienna, Austria #12;RISÃ?-R-411 NONLINEAR FINITE ELEMENT ANALYSIS OF CONCRETE STRUCTURES Niels Saabye Ottosen Abstract. This report deals with nonlinear finite element analy
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, Y.; Mahowald, N.; Scanza, R. A.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J. F.; Zhuang, G.; Chen, Y.; Cohen, D. D.; et al
2015-10-12
Trace element deposition from desert dust has important impacts on ocean primary productivity, the quantification of which could be useful in determining the magnitude and sign of the biogeochemical feedback on radiative forcing. However, the impact of elemental deposition to remote ocean regions is not well understood and is not currently included in global climate models. In this study, emission inventories for eight elements primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si are determined based on a global mineral data set and a soil data set. The resulting elemental fractions are used to drive themore »desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions is evident on a global scale, particularly for Ca. Simulations of global variations in the Ca / Al ratio, which typically range from around 0.1 to 5.0 in soils, are consistent with observations, suggesting that this ratio is a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different; estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observations of elemental aerosol concentrations from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions range from 0.7 to 1.6, except for Mg and Mn (3.4 and 3.5, respectively). Using the soil database improves the correspondence of the spatial heterogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust element fluxes to different ocean basins and ice sheet regions have been estimated, based on the model results. The annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using the mineral data set are 0.30 Tg, 16.89 Gg, 1.32 Tg, 22.84 Gg, 0.068 Tg, and 0.15 Tg to global oceans and ice sheets.« less