Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01T23:59:59.000Z
Vijayaraghavan, A. (2005), Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool ABSTRACT DEFORM-
Modeling a bender element test using Abaqus Finite Element Program
Johnson, Sean (Sean Michael)
2011-01-01T23:59:59.000Z
Finite Element Methods hold promise for modeling the behavior of an unsaturated soil specimen subjected to bender element agitation. The immediate objective of this research project is to reproduce a bender element test ...
A frequency domain finite element model for tidal circulation
Westerink, Joannes J.
1985-01-01T23:59:59.000Z
A highly efficient finite element model has been developed for the numerical prediction of depth average circulation within small scale embayments which are often characterized by irregular boundaries and bottom topography.
Compositional modeling of threephase flow with gravity using higherorder finite element methods
Firoozabadi, Abbas
Compositional modeling of threephase flow with gravity using higherorder finite element methods using higherorder finite element methods. Gravity poses complications in modeling multiphase processes flow with gravity using higherorder finite element methods, Water Resour. Res., 47, W05511, doi:10
Finite element modeling of syntactic foam.
Hobbs, Michael L.
2004-10-01T23:59:59.000Z
A decomposition model has been developed to predict the response of removable syntactic foam (RSF) exposed to fire-like heat fluxes. RSF consists of glass micro-balloons (GMB) in a cured epoxy polymer matrix. A chemistry model is presented based on the chemical structure of the epoxy polymer, mass transport of polymer fragments to the bulk gas, and vapor-liquid equilibrium. Thermophysical properties were estimated from measurements. A bubble nucleation, growth, and coalescence model was used to describe changes in properties with the extent of reaction. Decomposition of a strand of syntactic foam exposed to high temperatures was simulated.
An evaluation of finite element models of stiffened plates subjected to impulsive loading
Pedatzur, Omri
2004-01-01T23:59:59.000Z
Different finite element models are evaluated for two very common structures, a cantilever beam and a stiffened plate, subjected to impulsive loading. For the cantilever beam case, the finite element models are one, two ...
Energy conserving Anisotropic Anhysteretic Magnetic Modelling for Finite Element Analysis
Jens Krause
2012-12-20T23:59:59.000Z
To model ferromagnetic material in finite element analysis a correct description of the constitutive relationship (BH-law) must be found from measured data. This article proposes to use the energy density function as a centrepiece. Using this function, which turns out to be a convex function of the flux density, guarantees energy conservative modelling. The magnetic field strength can be seen as a derivative with respect to the flux density. Especially for anisotropic materials (from lamination and/or grain orientation) this method has advantages. Strictly speaking this method is only valid for anhysteretic and thermodynamically stable material.
Finite Element Multi-physics Modeling for Ohmic Contact of Microswitches , D. Leray1, 2
Boyer, Edmond
Finite Element Multi-physics Modeling for Ohmic Contact of Microswitches H.Liu1, 2 , D. Leray1, 2-physics modelling of electrical contact is accomplished with the finite element commercial package ANSYSTM . Two behaviour of electrical contact with rough surface included. Keywords: multi-physics, finite element
A Finite Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2013-11-02T23:59:59.000Z
We present a hydro-mechanical model, followed by stress, deformation, and shear-slip failure analysis for geological sequestration of carbon dioxide (CO2). The model considers the poroelastic effects by taking into account of the two-way coupling between the geomechanical response and the fluid flow process. Analytical solutions for pressure and deformation fields were derived for a typical geological sequestration scenario in our previous work. A finite element approach is introduced here for numerically solving the hydro-mechanical model with arbitrary boundary conditions. The numerical approach was built on an open-source finite element code Elmer, and results were compared to the analytical solutions. The shear-slip failure analysis was presented based on the numerical results, where the potential failure zone is identified. Information is relevant to the prediction of the maximum sustainable injection rate or pressure. The effects of caprock permeability on the fluid pressure, deformation, stress, and the shear-slip failure zone were also quantitatively studied. It was shown that a larger permeability in caprock and base rock leads to a larger uplift but a smaller shear-slip failure zone.
Surface photovoltage measurements and finite element modeling of SAW devices.
Donnelly, Christine
2012-03-01T23:59:59.000Z
Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.
Jackson, Jason R.
1996-01-01T23:59:59.000Z
CONSTITUTIVE MODEL EFFECTS ON FINITE ELEMENT MODELING OF ELASTOMER BEHAVIOR IN RADIAL INTERFERENCE SEAL CONFIGURATIONS A Thesis by JASON R. JACKSON Subnutted 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 1996 Major Subject: Mechanical Engineering CONSTITUTIVE MODEL EFFECTS ON FINITE ELEMENT MODELING OF ELASTOMER BEHAVIOR IN RADIAL INTERFERENCE SEAL CONFIGURATIONS A Thesis by JASON R. JACKSON...
Calibration under uncertainty for finite element models of masonry monuments
Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin
2010-02-01T23:59:59.000Z
Historical unreinforced masonry buildings often include features such as load bearing unreinforced masonry vaults and their supporting framework of piers, fill, buttresses, and walls. The masonry vaults of such buildings are among the most vulnerable structural components and certainly among the most challenging to analyze. The versatility of finite element (FE) analyses in incorporating various constitutive laws, as well as practically all geometric configurations, has resulted in the widespread use of the FE method for the analysis of complex unreinforced masonry structures over the last three decades. However, an FE model is only as accurate as its input parameters, and there are two fundamental challenges while defining FE model input parameters: (1) material properties and (2) support conditions. The difficulties in defining these two aspects of the FE model arise from the lack of knowledge in the common engineering understanding of masonry behavior. As a result, engineers are unable to define these FE model input parameters with certainty, and, inevitably, uncertainties are introduced to the FE model.
Analysis of a finite element formulation for modelling phase separation
Wells, G N; Garikipati, Krishna
2007-01-01T23:59:59.000Z
equation, which makes its numerical solution particularly challenging. To this end, a finite element formulation has been developed which can solve the Cahn-Hilliard equation in its primal form using C^0 basis functions. Here, analysis of a fully discrete...
Development of a finite element model of decompressive craniectomy
Fletcher, Tim L.; Kolias, Angelos G.; Hutchinson, Peter J. A.; Sutcliffe, Michael P. F.
2014-07-15T23:59:59.000Z
of high strains were comparatively small. Mesh. Axi-symmetric quadratic elements with reduced inte- gration (Abaqus element CAX8RPH) were used in all FE models. A fine mesh was created directly under the craniectomy edge with an average element length of 0...
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 variables Stephan Gadau, Ansgar J¨ungel, and Paola Pietra Abstract. One-dimensional stationary energy employing a mixed-hybrid finite- element method which has the advantage to fulfill current conser- vation
A FINITE ELEMENT MODEL FOR THE TIME-DEPENDENT JOULE HEATING PROBLEM*
Larsson, Stig
.3) 0 system models the electric heating* *ial differential equation describing the electric heating of a conducting body. We prove err* *or A FINITE ELEMENT MODEL FOR THE TIME-DEPENDENT JOULE HEATING PROBLEM
2003-12-06T23:59:59.000Z
FVE is closely related to the control volume finite element method ... simple stencils, to apply to a fairly wide range of fluid flow equations, to effectively treat.
Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites
Gaddamanugu, Dhatri
2010-07-14T23:59:59.000Z
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...
Lee, Sang Hoon
2012-02-14T23:59:59.000Z
, changing rock permeability. In this work, two- and three-dimensional finite element methods were developed to simulate coupled reservoirs with damage mechanics and stress-dependent permeability. The model considers the influence of fluid flow, temperature...
TEA - a linear frequency domain finite element model for tidal embayment analysis
Westerink, Joannes J.
1984-01-01T23:59:59.000Z
A frequency domain (harmonic) finite element model is developed for the numerical prediction of depth average circulation within small embayments. Such embayments are often characterized by irregular boundaries and bottom ...
Finite element decomposition and grid generation for brain modeling and visualization
Batte, David Allan
1997-01-01T23:59:59.000Z
Numerical grid generation is used to provide a framework for brain and neuron visualization. Smoothing spline surfaces are fit to contour data to generate 3D solid model reconstruction of brain tissues. Finite element methods are then used...
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method
Wang, G.; Liu, M.
2005-01-01T23:59:59.000Z
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method Gang Wang Research Associate University of Nebraska Lincoln Mingsheng Liu Professor University of Nebraska Lincoln David E. Claridge Professor Texas A... be decoupled using a constant sensible heat ratio (SHR) and the saturation humidity ratio vs. temperature curve can be treated as linear in a small area corresponding to a finite element of the coil. This paper presents the decoupled cooling coil model...
A finite element model for laminated composite plates with matrix cracks and delaminations
Buie, Kevin Daniel
1988-01-01T23:59:59.000Z
A FINITE ELEMENT MODEL FOR LAMINATED COMPOSITE PLATES WITH MATRIX CRACKS AND DELAMINATIONS A Thesis by KEVIN DANIEL BUIE Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of' the requirements... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Aerospace Engineering A FINITE ELEMENT MODEL FOR LAMINATED COMPOSITE PLATES WITH MATRIX CRACKS AND DELAMINATIONS A Thesis by KEVIN DANIEL BUIE Approved as to style and content by: David H...
The representation of boundary currents in a finite element shallow water model
Dben, Peter D
2015-01-01T23:59:59.000Z
We evaluate the influence of local resolution, eddy viscosity, coastline structure, and boundary conditions on the numerical representation of boundary currents in a finite element shallow-water model. The use of finite element discretization methods offers a higher flexibility compared to finite difference and finite volume methods, that are mainly used in previous publications. This is true for the geometry of the coast lines and for the realization of boundary conditions. For our investigations we simulate steady separation of western boundary currents from idealized and realistic coast lines. The use of grid refinement allows a detailed investigation of boundary separation at reasonable numerical cost.
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors
Pietra, Paola
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors Stefan Holst #12;tting mixed #12;nite-element method is used to discretize the stationary energy. Energy-transport models describe the ow of electrons through a semi- conductor device, in uenced by di
A Finite Element Algorithm of a Nonlinear Diffusive Climate Energy Balance Model
Díaz, Jesús 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
McArthur, Karl Edward
1996-01-01T23:59:59.000Z
, and constituent fluxes. The finite difference scheme in SW=D is based on a spatial discretization of the water body as a grid of equal sized, square cers. The model includes the effects of wetting and drying, wind, inflows and return flows, flow barriers...
Taylor, G.; Dong, C.; Sun, S.
2010-03-18T23:59:59.000Z
A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The finite volume method and the standard MFE method are used to approximate the convection and dispersion terms respectively. The model is used to investigate the interaction of adsorption with transport and to extract information on effective adsorption distribution coefficients. Numerical examples in different fractured media illustrate the robustness and efficiency of the proposed numerical model.
Finite-element discretization of a linearized 2 -D model for lubricated oil transportation
Frey, Pascal
Finite-element discretization of a linearized 2 - D model for lubricated oil transportation V acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy
On a tensor-based finite element model for the analysis of shell structures
Arciniega Aleman, Roman Augusto
2006-04-12T23:59:59.000Z
In the present study, we propose a computational model for the linear and nonlinear analysis of shell structures. We consider a tensor-based finite element formulation which describes the mathematical shell model in a natural and simple way by using...
A Finite-Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2014-09-01T23:59:59.000Z
Herein, we present a coupled thermal-hydro-mechanical model for geological sequestration of carbon dioxide followed by the stress, deformation, and shear-slip failure analysis. This fully coupled model considers the geomechanical response, fluid flow, and thermal transport relevant to geological sequestration. Both analytical solutions and numerical approach via finite element model are introduced for solving the thermal-hydro-mechanical model. Analytical solutions for pressure, temperature, deformation, and stress field were obtained for a simplified typical geological sequestration scenario. The finite element model is more general and can be used for arbitrary geometry. It was built on an open-source finite element code, Elmer, and was designed to simulate the entire period of CO2 injection (up to decades) both stably and accuratelyeven 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.
Puckett, A.D.
2000-09-01T23:59:59.000Z
The ability to model wave propagation in circular cylindrical bars of finite length numerically or analytically has many applications. In this thesis the capability of an explicit finite element method to model longitudinal waves in cylindrical rods with circular cross-sections is explored. Dispersion curves for the first four modes are compared to the analytical solution to determine the accuracy of various element sizes and time steps. Values for the time step and element size are determined that retain accuracy while minimizing computational time. The modeling parameters are validated by calculating a signal propagated with a broadband input force. Limitations on the applicability are considered along with modeling parameters that should be applicable to more general geometries.
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials
Paris-Sud XI, Universit de
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials A. Karrech a,, A. Seibi thrust is the introduc- tion of the "Chicago" law in a continuum approach to account for the ratcheting or jointly with the ratcheting effect. Non-associated plasticity is adopted since the paper mainly targets
A Finite Element Model for Ice Ball Evolution in a Multi-probe Cryosurgery
Wan, Richard G.
to intracellular ice injury for fast cooling rates, and solution effects injury for slow cooling rates. BasicallyA Finite Element Model for Ice Ball Evolution in a Multi-probe Cryosurgery RICHARD WANa, *, ZHIHONG October 2002; In final form 8 May 2003) The ice formation in a water body is examined for the computation
Suciu, Nicolae
A mixed finite element discretization scheme for a concrete carbonation model with concentration/unsaturated porous media. The special features of our problem are twofold: the reaction produces water and therefore for the case of concrete carbonation one of the most important physico-chemical processes affecting
Modeling of board-level package by Finite Element Analysis and laser interferometer measurements
Cao, Wenwu
and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai be simulated by an equivalent Finite Element Analysis (FEA) model of the board-level package, in which detailed layer structure of the Print Circuit Board (PCB), signal wires and through-holes were ignored
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...
Finite Element Modeling of the Fastening Systems and the Concrete
Barkan, Christopher P.L.
Sleeper and Ballast 0 500 1000 1500 2000 2500 3000 3500 4000 0.0000 0.0002 0.0004 0.0006 0.0008 0 of strands Rail seat area is between 0.39 m to 0.67 m Rail Seat Area Component Modeling: Concrete Sleeper Seat Area Position of concrete surface strain lt = 0.48 m Component Modeling: Concrete Sleeper
Probabilistic finite element analysis of marine risers
Leder, H. Vern
1990-01-01T23:59:59.000Z
Review 1. 2 Research Study 10 2 FORMULATION OF THE SECOND ? MOMENT ANALYSIS METHOD 13 2. 1 Finite Element Equations 2. 2 Random Vector Formulation 2. 3 The Correlation Function 2. 4 Random Field Discretization 2. 5 Taylor Series Expansion 2. 6... ILLUSTRATIVE EXAMPLE. . . . . . . . . . . . . . . . . . 4 APPLICATION OF PROBABILISTIC FINITE ELEMENT METHODS TO MARINE RISER ANALYSES 4. 1 Finite Element Model . 4. 1. 1 Formulation of the Equation of Motion 4. 1. 2 Finite Element Discretization 4. 1. 3...
Phase Reduction Models for Improving the Accuracy of the Finite Element Solution of
Boyer, Edmond
, acoustic scattering, short-wave problem, finite element method, pollution, accuracy, On-Surface Radiation in view of a numerical finite element solution. It is well-known that pollution error causes inaccuracies the pollution error in the finite element solution of time-harmonic scattering problems. The pollution error
Boyer, Edmond
identification method - associating a direct finite element model of Gleeble tests and an optimization module1 Inverse Finite Element Modelling and Identification of Constitutive Parameters of UHS Steel Based-2 ) hc heat transfer coefficient at interface between specimen and grips (W m-2 K) hth_eff effective
Simulation of dynamic fracture using peridynamics, finite element modeling, and contact.
Littlewood, David John
2010-11-01T23:59:59.000Z
Peridynamics is a nonlocal extension of classical solid mechanics that allows for the modeling of bodies in which discontinuities occur spontaneously. Because the peridynamic expression for the balance of linear momentum does not contain spatial derivatives and is instead based on an integral equation, it is well suited for modeling phenomena involving spatial discontinuities such as crack formation and fracture. In this study, both peridynamics and classical finite element analysis are applied to simulate material response under dynamic blast loading conditions. A combined approach is utilized in which the portion of the simulation modeled with peridynamics interacts with the finite element portion of the model via a contact algorithm. The peridynamic portion of the analysis utilizes an elastic-plastic constitutive model with linear hardening. The peridynamic interface to the constitutive model is based on the calculation of an approximate deformation gradient, requiring the suppression of possible zero-energy modes. The classical finite element portion of the model utilizes a Johnson-Cook constitutive model. Simulation results are validated by direct comparison to expanding tube experiments. The coupled modeling approach successfully captures material response at the surface of the tube and the emerging fracture pattern. The coupling of peridynamics and finite element analysis via a contact algorithm has been shown to be a viable means for simulating material fracture in a high-velocity impact experiment. A combined peridynamics/finite element approach was applied to model an expanding tube experiment performed by Vogler, et al., in which loading on the tube is a result of Lexan slugs impacting inside the tube. The Lexan portion of the simulation was modeled with finite elements and a Johnson-Cook elastic-plastic material model in conjunction with an equation-of-state law. The steel tube portion of the simulation was modeled with peridynamics, an elastic-plastic material model, and a critical stretch bond damage model. The application of peridynamics to the tube portion of the model allowed the capture of the formation of cracks and eventual fragmentation of the tube. The simulation results yielded good agreement with the experimental results published by Vogler, et al., for the velocity and displacement profiles on the surface of the tube and the resulting fragment distribution. Numerical difficulties were encountered that required removal of hexahedron elements from the Lexan portion of the model over the course of the simulation. The significant number of inverted and nearly-inverted elements appearing over the course of the simulation is believed to be a result of irregularities in the contact between the Lexan and AerMet portions of the model, and was likely exacerbated by the ultra-high strength of the AerMet tube. Future simulations are planned in which the Lexan portion of the simulation is modeled with peridynamics, or with an alternative method such as smoothed particle hydrodynamics, with the goal of reducing these numerical difficulties.
Boyer, Edmond
- 1 - Implementation of surface tension with wall adhesion effects in a three-dimensional finite element modelling of surface tension. The external stress vectors associated with surface tension a drop of liquid on a plane is treated. Keywords : surface tension, finite element method, average
Modeling of reactor components using FIDAP: a finite element computer code
Gangadharan, Anand
1989-01-01T23:59:59.000Z
of MASTER OF SCIENCE May 1989 Major Subject: Nuclear Engineering MODELING OF REACTOR COMPONENTS USING FIDAP - A FINITE ELEMENT COMPUTER CODE A Thesis by ANAND GANGADHARAN Approved as to style and content by. assin A. Hassan (Chair of Committee... of Nuclear Engineering, Texas ASM University. I feel elated in placing on record, my direct and totally involved interaction with the Chairman of my committee, Prof. Y. A. Hassan. I am grateful to him for his constant and unreserved encouragement...
Leng, Wei [Chinese Academy of Sciences; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University; Price, Stephen [Los Alamos National Laboratory; Ringler, Todd [Los Alamos National Laboratory,
2012-01-01T23:59:59.000Z
The numerical modeling of glacier and ice sheet evolution is a subject of growing interest, in part because of the potential for models to inform estimates of global sea level change. This paper focuses on the development of a numerical model that determines the velocity and pressure fields within an ice sheet. Our numerical model features a high-fidelity mathematical model involving the nonlinear Stokes system and combinations of no-sliding and sliding basal boundary conditions, high-order accurate finite element discretizations based on variable resolution grids, and highly scalable parallel solution strategies, all of which contribute to a numerical model that can achieve accurate velocity and pressure approximations in a highly efficient manner. We demonstrate the accuracy and efficiency of our model by analytical solution tests, established ice sheet benchmark experiments, and comparisons with other well-established ice sheet models.
A finite element model for transient thermal/structural analysis of large composite space structures
Lutz, James Delmar
2012-06-07T23:59:59.000Z
on approximate 6 analysis techniques based on finite elements has begun. Such techniques as reduced basis techniques and generalized transform methods offer hope of solving the finite element 8 equations more efficiently. An integrated thermal/structural... integrated analysis codes. However, Mahaney, Thornton, and Dechaumphai have identified require 5 ments for such thermal/structural programs. They concluded that such analysis methods should have the following five characteristics. First, a common finite...
Efficient Computation of Info-Gap Robustness for Finite Element Models
Stull, Christopher J. [Los Alamos National Laboratory; Hemez, Francois M. [Los Alamos National Laboratory; Williams, Brian J. [Los Alamos National Laboratory
2012-07-05T23:59:59.000Z
A recent research effort at LANL proposed info-gap decision theory as a framework by which to measure the predictive maturity of numerical models. Info-gap theory explores the trade-offs between accuracy, that is, the extent to which predictions reproduce the physical measurements, and robustness, that is, the extent to which predictions are insensitive to modeling assumptions. Both accuracy and robustness are necessary to demonstrate predictive maturity. However, conducting an info-gap analysis can present a formidable challenge, from the standpoint of the required computational resources. This is because a robustness function requires the resolution of multiple optimization problems. This report offers an alternative, adjoint methodology to assess the info-gap robustness of Ax = b-like numerical models solved for a solution x. Two situations that can arise in structural analysis and design are briefly described and contextualized within the info-gap decision theory framework. The treatments of the info-gap problems, using the adjoint methodology are outlined in detail, and the latter problem is solved for four separate finite element models. As compared to statistical sampling, the proposed methodology offers highly accurate approximations of info-gap robustness functions for the finite element models considered in the report, at a small fraction of the computational cost. It is noted that this report considers only linear systems; a natural follow-on study would extend the methodologies described herein to include nonlinear systems.
Barham, M; White, D; Steigmann, D; Rudd, R
2009-04-08T23:59:59.000Z
Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.
Parallel 3D Finite Element Numerical Modelling of DC Electron Guns
Prudencio, E.; Candel, A.; Ge, L.; Kabel, A.; Ko, K.; Lee, L.; Li, Z.; Ng, C.; Schussman, G.; /SLAC
2008-02-04T23:59:59.000Z
In this paper we present Gun3P, a parallel 3D finite element application that the Advanced Computations Department at the Stanford Linear Accelerator Center is developing for the analysis of beam formation in DC guns and beam transport in klystrons. Gun3P is targeted specially to complex geometries that cannot be described by 2D models and cannot be easily handled by finite difference discretizations. Its parallel capability allows simulations with more accuracy and less processing time than packages currently available. We present simulation results for the L-band Sheet Beam Klystron DC gun, in which case Gun3P is able to reduce simulation time from days to some hours.
DOLFIN: Automated Finite Element Computing
Logg, Anders; Wells, G N
2009-01-01T23:59:59.000Z
delec 1980]. (4) L2-conforming finite elements: (a) DGq, arbitrary degree discontinuous Lagrange elements; and (b) CR1, first degree CrouzeixRaviart5 elements [Crouzeix and Raviart 1973]. Arbitrary combinations of the above elements may be used to define...
Finite Element Analysis of the Amontons-Coulomb's Model using Local and Global Friction Tests
Oliveira, M. C.; Menezes, L. F.; Ramalho, A. [CEMUC, Department of Mechanical Engineering, University of Coimbra, Polo II, Rua Luis Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra (Portugal); Alves, J. L. [Department of Mechanical Engineering, University of Minho, Campus de Azurem, 4800-058, Guimaraes (Portugal)
2011-05-04T23:59:59.000Z
In spite of the abundant number of experimental friction tests that have been reported, the contact with friction modeling persists to be one of the factors that determine the effectiveness of sheet metal forming simulation. This difficulty can be understood due to the nature of the friction phenomena, which comprises the interaction of different factors connected to both sheet and tools' surfaces. Although in finite element numerical simulations friction models are commonly applied at the local level, they normally rely on parameters identified based on global experimental tests results. The aim of this study is to analyze the applicability of the Amontons-Coulomb's friction coefficient identified using complementary tests: (i) load-scanning, at the local level and (ii) draw-bead, at the global level; to the numerical simulation of sheet metal forming processes.
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
reliability. Short-tubes have either a constant inner dia- meter flow channel or a tapered channel with a smallAbstract A finite element model was used to simulate single-phase flow of R-22 through flexible short-tubes. The numerical model included the fluid... in the flow area. The more flexible (5513 kPa) short-tube restricted the mass flow rate more than the most rigid (9889 kPa) short-tube used in this study. The mass flow rates estimated with the finite element model were as much as 14% higher than those from...
electroseismic monitoring of co2 sequestration: a finite element ...
Fabio Zyserman
Keywords: Electroseismic Modeling, Poroelasticity, CO2 sequestration, Finite element methods. 2000 AMS ... carbon dioxide emissisons into the atmosphere.
Quantum-corrected drift-diffusion models: Solution fixed point map and finite element approximation
Falco, Carlo de [School of Mathematical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Jerome, Joseph W. [Department of Mathematics, Northwestern University, 2033 Sheridan Road, Evanston, IL 60208-2730 (United States); Sacco, Riccardo [Dipartimento di Matematica 'F.Brioschi', Politecnico di Milano, via Bonardi 9, 20133 Milano (Italy)], E-mail: riccardo.sacco@polimi.it
2009-03-20T23:59:59.000Z
This article deals with the analysis of the functional iteration, denoted Generalized Gummel Map (GGM), proposed in [C. de Falco, A.L. Lacaita, E. Gatti, R. Sacco, Quantum-Corrected Drift-Diffusion Models for Transport in Semiconductor Devices, J. Comp. Phys. 204 (2) (2005) 533-561] for the decoupled solution of the Quantum Drift-Diffusion (QDD) model. The solution of the problem is characterized as being a fixed point of the GGM, which permits the establishment of a close link between the theoretical existence analysis and the implementation of a numerical tool, which was lacking in previous non-constructive proofs [N.B. Abdallah, A. Unterreiter, On the stationary quantum drift-diffusion model, Z. Angew. Math. Phys. 49 (1998) 251-275, R. Pinnau, A. Unterreiter, The stationary current-voltage characteristics of the quantum drift-diffusion model, SIAM J. Numer. Anal. 37 (1) (1999) 211-245]. The finite element approximation of the GGM is illustrated, and the main properties of the numerical fixed point map (discrete maximum principle and order of convergence) are discussed. Numerical results on realistic nanoscale devices are included to support the theoretical conclusions.
Minimizing EIT image artefacts from mesh variability in Finite Element Models
Adler, Andy
artefacts which occur in electrical impedance tomography (EIT) images due to limitations in finite element R B Lionheart2 1 Systems and Computer Engineering, Carleton University, Ottawa, Canada 2 School of Mathematics, University of Manchester, UK Abstract. Electrical Impedance Tomography solves an inverse problem
Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.
Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay
2012-01-01T23:59:59.000Z
Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.
Finite element modelling of transport and drift effects in tokamak divertor and SOL
Simard, M.; Marchand, R. [INRS-Energie et Materiaux, Varennes, Quebec (Canada); Boucher, C.; Gunn, J.P. [Centre Canadien de Fusion Magnetique, Varennes, Quebec (Canada)] [and others
1996-12-31T23:59:59.000Z
A finite element code is used to simulate transport of a single-species plasma in the edge and divertor of a tokamak. The physical model is based on Braginskii`s fluid equations for the conservation of particles, parallel momentum, ion and electron energy. In modelling recycling, transport of neutral density and energy is treated in the diffusion approximation. The electrostatic potential is obtained from the generalized Ohm`s law. It is used to compute the electric field and the associated E x B drift. In a first approximation, transport is assumed to be ambipolar. The system of equations is discretized on an unstructured triangular mesh, thus permitting good spatial resolution near the X-point and an accurate description of divertor plates of arbitrary shape. Special care must be taken to prevent numerical corruption of the highly anisotropic thermal diffusion. Comparisons will be made between simulations and experimental results from TdeV. This will focus, in particular, on density and temperature profiles at the divertor plates, and on the plasma parallel velocity in the SOL. The asymmetry in the power deposited to the inner and outer divertors and the effect of magnetic field reversal will be considered. Comparisons with B2-Eirene simulation results will also be presented.
A multiscale preconditioner for stochastic mortar mixed finite elements
Yotov, Ivan
physical models in different subdomains. The mortar finite element method is a generalization is the stochastic collocation method [4,40,39]. It combines a finite element discretiza- tion in physical space the approximation properties of the stochastic finite element method [5,37], making it more efficient than MCS
Koteras, J.R.
1993-07-01T23:59:59.000Z
Tunnels buried deep within the earth constitute an important class geomechanics problems. Two numerical techniques used for the analysis of geomechanics problems, the finite element method and the boundary element method, have complementary characteristics for applications to problems of this type. The usefulness of combining these two methods for use as a geomechanics analysis tool has been recognized for some time, and a number of coupling techniques have been proposed. However, not all of them lend themselves to efficient computational implementations for large-scale problems. This report examines a coupling technique that can form the basis for an efficient analysis tool for large scale geomechanics problems through the use of an iterative equation solver.
Adaptive Finite Element Modeling Techniques for the Poisson-Boltzmann Equation
Michael Holst; James Andrew McCammon; Zeyun Yu; Yongcheng Zhou; Yunrong Zhu
2010-09-30T23:59:59.000Z
We develop an efficient and reliable adaptive finite element method (AFEM) for the nonlinear Poisson-Boltzmann equation (PBE). We first examine the regularization technique of Chen, Holst, and Xu; this technique made possible the first a priori pointwise estimates and the first complete solution and approximation theory for the Poisson-Boltzmann equation. It also made possible the first provably convergent discretization of the PBE, and allowed for the development of a provably convergent AFEM for the PBE. However, in practice the regularization turns out to be numerically ill-conditioned. In this article, we examine a second regularization, and establish a number of basic results to ensure that the new approach produces the same mathematical advantages of the original regularization, without the ill-conditioning property. We then design an AFEM scheme based on the new regularized problem, and show that the resulting AFEM scheme is accurate and reliable, by proving a contraction result for the error. This result, which is one of the first results of this type for nonlinear elliptic problems, is based on using continuous and discrete a priori pointwise estimates to establish quasi-orthogonality. To provide a high-quality geometric model as input to the AFEM algorithm, we also describe a class of feature-preserving adaptive mesh generation algorithms designed specifically for constructing meshes of biomolecular structures, based on the intrinsic local structure tensor of the molecular surface. The stability advantages of the new regularization are demonstrated using an FETK-based implementation, through comparisons with the original regularization approach for a model problem. The convergence and accuracy of the overall AFEM algorithm is also illustrated by numerical approximation of electrostatic solvation energy for an insulin protein.
Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA); Foster, C. D. (Stanford University, Stanford, CA)
2006-10-01T23:59:59.000Z
Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report focuses on the development of a constitutive model appropriate to localizing geomaterials, and the embedding of this model into the enhanced finite element framework. This modeling covers two distinct phases. The first, usually brief, phase is the weakening response as the material transitions from intact continuum to a body with a cohesionless fractured surface. Once the cohesion has been eliminated, the response along the surface is completely frictional. We have focused on a rate- and state-dependent frictional model that captures stable and unstable slip along the surface. This model is embedded numerically into the element using a generalized trapezoidal formulation. While the focus is on the constitutive model of interest, the framework is also developed for a general surface response. This report summarizes the major research and development accomplishments for the LDRD project titled 'Cohesive Zone Modeling of Failure in Geomaterials: Formulation and Implementation of a Strong Discontinuity Model Incorporating the Effect of Slip Speed on Frictional Resistance'. This project supported a strategic partnership between Sandia National Laboratories and Stanford University by providing funding for the lead author, Craig Foster, during his doctoral research.
INTRODUCTION TO THE FINITE ELEMENT METHOD
California at Berkeley, University of
in popularity with the finite difference method in the areas of heat transfer and fluid mechanics. 1DRAFT Chapter 1 INTRODUCTION TO THE FINITE ELEMENT METHOD 1.1 Historical perspective: the origins of the finite el- ement method The finite element method constitutes a general tool for the numerical solution
E-Print Network 3.0 - art finite element Sample Search Results
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system. We generated finite element models of the Boeing 767 and of the top 20 stories of the North Tower... elements. The finite ... Source: Irfanoglu, Ayhan - School of...
Antoine, Xavier - Institut de Mathématiques ?lie Cartan, Université Henri Poincaré
Accepted 12 January 2009 Available online 21 January 2009 Keywords: Helmholtz equation Acoustic scattering Short-wave problem Finite element method Pollution Accuracy On-Surface Radiation Condition method a b- lems in view of a numerical finite element solution. It is well-known that pollution error causes
Lau, Ryan
2007-09-17T23:59:59.000Z
Relatively little is known about marine controlled-source electromagnetic surveys (MCSEM) used to detect hydrocarbon reservoirs. Typical MCSEM require the use of inversion to generate a model of the subsurface. We utilize a 3D finite-element forward...
De Castro, Carlos Armando
2011-01-01T23:59:59.000Z
In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.
Finite element analysis of human joints
Bossart, P.L.; Hollerbach, K.
1996-09-01T23:59:59.000Z
Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.
Sudarshan, Raghunathan, 1978-
2005-01-01T23:59:59.000Z
We propose a simple and unified approach for a posteriori error estimation and adaptive mesh refinement in finite element analysis using multiresolution signal processing principles. Given a sequence of nested discretizations ...
James, Stephen M.
2011-08-08T23:59:59.000Z
-dimensional axisymmetric beam-element code. ANSYS is used as a code to build three-dimensional non-axisymmetric solid-element casing models. The work done in this thesis opens the scope to incorporate complex non-axisymmetric casing models with XLTRC2....
Finite element approximation of coupled seismic and ...
zyserman
layer, having a thickness of about 10 nm. Finite element approximation of coupled seismic and electromagnetic waves in gas hydrate-bearing sediments p.
On simple and accurate finite element models for nonlinear bending analysis of beams and plates
Urthaler Lapeira, Yetzirah Yksya
2007-09-17T23:59:59.000Z
that rotates with the element and with respect to which the standard linear engineering relations between strains and internal forces are valid. The element is based on Lagrange interpolation of the axial displacement, Hermite cubic interpolation...
Finite Element Modelling of the Sawing of DC Cast AA2024 Aluminium Alloy Slabs
Drezet, J.-M. [Computational Materials Laboratory, School of Engineering, Ecole Polytechnique Federale de Lausanne, Station 12, CH-1015 Lausanne (Switzerland); Ludwig, O. [Calcom-ESI SA, PSE-A, CH-1015 Lausanne (Switzerland); Heinrich, B. [Alcan Aluminium Valais SA, CH3960 Sierre (Switzerland)
2007-04-07T23:59:59.000Z
In the semi-continuous casting of large cross-section rolling sheet ingots of high-strength aluminum alloys (2xxx and 7xxx series), the control of the residual (internal) stresses generated by the non-uniform cooling becomes a necessity. These stresses must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts may be ejected thus injuring people or damaging equipment. These high added-value ingots need to be produced in secure conditions. Moreover, a better control of the sawing procedure could allow the suppression of the thermal treatment and therefore save time and energy. By studying the stress build-up during casting and the stress relief during sawing, key parameters for the control and optimization of the processing steps, can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy is modeled with ABAQUS 6.5 with special attention to the thermo-mechanical properties of the alloy. The sawing operation is then simulated by removing mesh elements so as to reproduce the progression of the saw in the ingot. Preliminary results showing the stress relief during sawing accompanied by the risk of saw blocking due to compression or initiating a crack ahead of the saw, are analyzed with an approach based on the rate of strain energy release.
Mixed finite element discretization of a model for organic pollution in waters
Paris-Sud XI, Université de
of the DO and its flux at the boundary. Currently, no oxygen flux is generated by the environmental medium the Biochemical Oxygen Demand and Dissolved Oxygen to which dispersion terms are added. In this work, we propose. The central element of such problems is the oxygen. The main tracers currently used are the density b
Pettit, J. R. [Rolls-Royce Nuclear, PO BOX 2000, Derby, UK, DE21 7XX and Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Walker, A. [Rolls-Royce Nuclear, PO BOX 2000, Derby DE21 7XX (United Kingdom); Lowe, M. J. S. [Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2014-02-18T23:59:59.000Z
Defects which posses rough surfaces greatly affect ultrasonic wave scattering behaviour, often reducing the magnitude of reflected signals. Ultrasonic inspections rely upon this response for detecting and sizing flaws. For safety critical components reliable characterisation is crucial. Therefore, providing an accurate means to predict reductions in signal amplitude is essential. An extension of Kirchhoff theory has formed the basis for the UK power industry inspection justifications. However, it is widely recognised that these predictions are pessimistic owing to analytical approximations. A numerical full field modelling approach does not fall victim to such limitations. Here, a Finite Element model is used to aid in setting a non-conservative reporting threshold during the inspection of a large pressure vessel forging that might contain embedded rough defects. The ultrasonic response from multiple rough surfaces defined by the same statistical class is calculated for normal incident compression waves. The approach is validated by comparing coherent scattering with predictions made by Kirchhoff theory. At lower levels of roughness excellent agreement is observed, whilst higher values confirm the pessimism of Kirchhoff theory. Furthermore, the mean amplitude in the specular direction is calculated. This represents the information obtained during an inspection, indicating that reductions due to increasing roughness are significantly less than the coherent component currently being used.
A multi-scale iterative approach for finite element modeling of thermal contact resistance
Thompson, Mary Kathryn, 1980-
2007-01-01T23:59:59.000Z
Surface topography has long been considered a key factor in the performance of many contact applications including thermal contact resistance. However, essentially all analytical and numerical models of thermal contact ...
An elastic-perfectly plastic flow model for finite element analysis of perforated materials
Jones, D.P.; Gordon, J.L.; Hutula, D.N.; Banas, D.; Newman, J.B.
1999-02-01T23:59:59.000Z
This paper describes the formulation of an elastic-perfectly plastic flow theory applicable to equivalent solid [EQS] modeling of perforated materials. An equilateral triangular array of circular penetrations is considered. The usual assumptions regarding geometry and loading conditions applicable to the development of elastic constants for EQS modeling of perforated plates are considered to apply here. An elastic-perfectly plastic [EPP] EQS model is developed for a collapse surface that includes fourth-order stress terms. The fourth order yield function has been shown to be appropriate for plates with a triangular array of circular holes. A complete flow model is formulated using the consistent tangent modulus approach based on the fourth order yield function.
Mongkolcheep, Kathira
2010-10-12T23:59:59.000Z
The purpose of this work is to present a methodology to predict vibrations of drilllstrings for oil recovery service. The work extends a previous model of the drill collar between two stabilizers in the literature to include drill collar flexibility...
k - Version of Finite Element Method for Polymer flows using Giesekus Constitutive Model
Deshpande, Kedar M.
2008-01-31T23:59:59.000Z
and hence high Deborah number flows are invariably associated with higher flow rates and thus higher velocities. In many standard model problems such as couette flow, lid driven cavity, expansion, contraction etc, severe deborah number (De) limitations...
A finite element model of the turbulent flow field in a centrifugal impeller
Hlavaty, Steven Todd
1993-01-01T23:59:59.000Z
, or for applications such as pumps utilizing a liquid as the working medium. Full ellipticity of the flow- governing equations throughout the computational domain is rigorously retained. As a result, the model is conceptually capable of predicting real-flow effects... such as flow separation and recirculation, regardless of whether such complex flow behavior is local or massive. Applicability of the model is illustrated using a typical pump impeller of the purely centrifugal type. In presenting the computed flow field...
adaptive finite element: Topics by E-print Network
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properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
adaptive finite elements: Topics by E-print Network
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properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
Styles, Vanessa
FOR SUPERCONDUCTIVITY C.M. ELLIOTT, D. KAY #3; AND V.STYLES y CENTRE FOR MATHEMATICAL ANALYSIS AND ITS APPLICATIONS long cylindrical superconductor subject to a transverse magnetic #12;eld. We prove an error between of an evolutionary variational inequality arising from a critical state model for a type-II superconductor
Finite element and nite volume discretizations of Drift-Di usion type uid models for semiconductors
Brezzi, Franco
Milano Via Bonardi 9, 20133 Milano, Italy z University of Western Australia Department of Mathematics and Statistics Nedlands, Western Australia 6907, Australia This paper is to appear as a Chapter of Numerical the initial/boundary conditions which complete the model. We also consider in more detail the Energy
Impeller deflection and modal finite element analysis.
Spencer, Nathan A.
2013-10-01T23:59:59.000Z
Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.
Finite Element Modeling of Suspended Particle Migration in Non-Newtonian Fluids
Altobelli, S.; Baer, T.; Mondy, L.; Rao, R.; Stephens, T.
1999-03-04T23:59:59.000Z
Shear-induced migration of particles is studied during the slow flow of suspensions of spheres (particle volume fraction {phi} = 0.50) in an inelastic but shear-thinning, suspending fluid in flow between counterrotating concentric cylinders, The conditions are such that nonhydrodynamic effects are negligible. The movement of particles away from the high shear rate region is more pronounced than in a Newtonian suspending liquid. We test a continuum constitutive model for the evolution of particle concentration in a flowing suspension proposed by Phillips et al. (1992) by using shear-thinning, suspending fluids. The fluid constitutive equation is Carreau-like in its shear-thinning behavior but also varies with the local particle concentration. The model is compared with the experimental data gathered with nuclear magnetic resonance (NMR) imaging.
Application of Mass Lumped Higher Order Finite Elements
Chen, J.; Strauss, H. R.; Jardin, S. C.; Park, W.; Sugiyama, L. E.; Fu., G.; Breslau, J.
2005-11-01T23:59:59.000Z
There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied.
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II Zhangxin coefficient times the gradient). Based on this formulation, mixed finite element approximations with low permeability and to the transport equation with small dispersion in groundwater modeling
Quadrilateral/hexahedral finite element mesh coarsening
Staten, Matthew L; Dewey, Mark W; Scott, Michael A; Benzley, Steven E
2012-10-16T23:59:59.000Z
A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.
Discontinuous Galerkin finite element methods for gradient plasticity.
Garikipati, Krishna. (University of Michigan, Ann Arbor, MI); Ostien, Jakob T.
2010-10-01T23:59:59.000Z
In this report we apply discontinuous Galerkin finite element methods to the equations of an incompatibility based formulation of gradient plasticity. The presentation is motivated with a brief overview of the description of dislocations within a crystal lattice. A tensor representing a measure of the incompatibility with the lattice is used in the formulation of a gradient plasticity model. This model is cast in a variational formulation, and discontinuous Galerkin machinery is employed to implement the formulation into a finite element code. Finally numerical examples of the model are shown.
Langerman, M.A.
1990-09-01T23:59:59.000Z
Steady-state modeling considerations for simulating the in situ vitrification (ISV) process are documented based upon the finite element numerical approach. Recommendations regarding boundary condition specifications and mesh discretization are presented. The effects of several parameters on the ISV process response are calculated and the results discussed. The parameters investigated include: (1) electrode depth, (2) ambient temperature, (3) supplied current, (4) electrical conductivity, (5) electrode separation, and (6) soil/waste characterization. 13 refs., 29 figs., 1 tab.
Generalized finite element method for Helmholtz equation
Hidajat, Realino Lulie
2009-05-15T23:59:59.000Z
reduces the pollution effect due to wave number and we are able to obtain a highly accurate solution with a much smaller number of degrees-of-freedom compared with the classical Finite Element Method. The q-convergence of the handbook functions...
Min, Kyoung
2013-07-16T23:59:59.000Z
equation. Using a new moving-boundary element partition methodology (EPM), fracture propagation through heterogeneous media is predicted simply and efficiently. The method allows coupling fluid flow and rock deformation, and fracture propagation using...
An Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow
Osnes, Harald
of groundwater flow and transport from mathematical models involves considerable uncertainty due to the presenceAn Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow Harald Osnes Hans by nonlinear effects as oe Y approaches unity in more general domains. 1 #12; 1 Introduction The prediction
Interval Finite Element Methods: New Directions Rafi Muhanna1
Kreinovich, Vladik
Interval Finite Element Methods: New Directions Rafi Muhanna1 , Vladik Kreinovich2 , Pavel Sol´in2 advanced numerical methods to tackle these problems, such as finite element methods (FEM). Lately, new advanced version of these methods have appeared, such as hierarchic higher-order finite element methods (hp
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert
Treuille, Adrien
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert Carnegie Mellon University Global be solved numerically. In this chapter we explain some of the basics of the finite element method Illumination course notes, SIGGRAPH '93, Anaheim, Aug. 1993 41 #12; 42 Introduction to Finite Element Methods
Dynamic analysis of mechanisms by finite elements
Botsali, F.M.; Uenuevar, A. [Selcuk Univ., Konya (Turkey). Mechanical Engineering Dept.
1996-11-01T23:59:59.000Z
The need to increase productivity in order to decrease manufacturing costs lead to an increase in the working speeds of machines and mechanical systems used in manufacturing. A method is presented for investigating the dynamics of mechanisms with elastic links. Finite element method is used in the formulation of the dynamic problem. Modal transformation is used in order to reduce the number of equations of motion. Using the presented technique, elastic and rigid body motions of mechanism links are solved simultaneously. The presented method may be applied to spatial and open loop mechanisms including robot manipulators as well.
Rushing, John Ford
2014-04-25T23:59:59.000Z
potential laboratory tests, (b) comparisons of laboratory tests results to full-scale accelerated pavement test results, and (c) analyses of results from finite element simulations. The laboratory study evaluated of the repeated load test, the static creep...
An application of stochastic finite element method in structural reliabiity
Agrawal, Sanjay
1993-01-01T23:59:59.000Z
OF SCIENCE August 1993 Major Subject: Civil Engineering AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SANJAY AGRAWAL Approved as to style and content by: Kostas apadimitriou (Chair of Committee) John M... of the beam on the buckling load. The statistical methodology can be efficiently used with available FORM/SORM reliability techniques to compute the probability of failure of the beam due to buckling. Random fields are used to quantify the modeling...
Morris, J; Johnson, S
2007-12-03T23:59:59.000Z
The Distinct Element Method (also frequently referred to as the Discrete Element Method) (DEM) is a Lagrangian numerical technique where the computational domain consists of discrete solid elements which interact via compliant contacts. This can be contrasted with Finite Element Methods where the computational domain is assumed to represent a continuum (although many modern implementations of the FEM can accommodate some Distinct Element capabilities). Often the terms Discrete Element Method and Distinct Element Method are used interchangeably in the literature, although Cundall and Hart (1992) suggested that Discrete Element Methods should be a more inclusive term covering Distinct Element Methods, Displacement Discontinuity Analysis and Modal Methods. In this work, DEM specifically refers to the Distinct Element Method, where the discrete elements interact via compliant contacts, in contrast with Displacement Discontinuity Analysis where the contacts are rigid and all compliance is taken up by the adjacent intact material.
CharacteristicGalerkin and Mixed Finite Element Approximation of Contamination by Compressible
Chou, So-Hsiang
CharacteristicGalerkin and Mixed Finite Element Approximation of Contamination by Compressibledisposal contamination in porous media is modeled by a coupled system of partial differential equations for the brine, radionuclides, and heat and by a mixed finite element method for the pressure and velocity
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS
Rodríguez, Rodolfo
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS FELIPE LEPE for Timo- shenko beams. It is known that standard finite elements applied to this model lead to wrong results when the thickness of the beam t is small. Here, we consider a mixed formulation in terms
Ewing, Richard E.
A ThreeDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination of South Carolina, Columbia, South Carolina ABSTRACT: Model equations for transport of nuclearwaste based up on the inherent physics. A threedimensional finite element method for nuclear waste
3-D Finite Element Analyses of the Egan Cavern Field
Klamerus, E.W.; Ehgartner, B.L.
1999-02-01T23:59:59.000Z
Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were moderate to excessive depending on the salt creep properties and operating pressures. However, subsidence above the cavern field was small and should pose no problem, to surface facilities.
Finite element simulation and parameter optimization of a flexible tactile pressure sensor array
Lee, Shira M. (Shira Miriam)
2005-01-01T23:59:59.000Z
A finite element model was developed to optimize design of a flexible tactile sensor. The sensor consists of layers of thin-film copper and PDMS, and the model can be used to determine the effects on sensor sensitivity and ...
Curved finite elements by the method of initial strains
Leick, Roger Dale
1974-01-01T23:59:59.000Z
, pp. 383-432. 2. Clough, R. W. , "Comparison of Three Dimensional Finite Elements, " Proceedin s of the S osium on A lication of Finite Element Mhd l. t''i~Et f, Vd6'ltUt ty, 1969, pp. 1-26. 3. Stricklin, J. A. , informal proposal submitted to Dr...
Parallel Finite Element Simulation of Tracer Injection in Oil Reservoirs
Coutinho, Alvaro L. G. A.
Parallel Finite Element Simulation of Tracer Injection in Oil Reservoirs Alvaro L.G.A. Coutinho In this work, parallel finite element techniques for the simulation of tracer injection in oil reservoirs. Supercomputers have made it possible to consider global reservoir effects which can not be represented using
Regueiro, Richard A.
, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneously
B-spline finite elements for plane elasticity problems
Aggarwal, Bhavya
2007-04-25T23:59:59.000Z
. The k-refinement is reported to be much more efficient and robust than the standard h or p- refinement used in the conventional FEM models. Besides the use of B-spline functions for structural problems, they have been used in some other fields as well... and convergence behavior. The paper reports a reduction in the numerical cost using B-spline FEM. The use of the B-spline finite element method for the thermistor problem [29,30] and for a numerical solution of Burger?s equation[31- 33] has been successfully...
Current commutator anomalies in finite-element quantum electrodynamics
Dean F. Miller
1993-12-20T23:59:59.000Z
Four-dimensional quantum electrodynamics has been formulated on a hypercubic Minkowski finite-element lattice. The equations of motion have been derived so as to preserve lattice gauge invariance and have been shown to be unitary. In addition, species doubling is avoided due to the nonlocality of the interactions. The model is used to investigate the lattice current algebra. Regularization of the current is shown to arise in a natural and nonarbitrary way. The commutators of the lattice current are calculated and shown to have the expected qualitative behavior. These lattice results are compared to various continuum calculations. (Five figures available from author.)
Harrison, Mark
, isotropic, composite system consisting of a fluid-filled well bore Qf through a fluid-saturated porous solid-filled borehole Qf through a fluid-saturated porous solid Qp. The problem arises naturally in acoustic well in the model. This paper is related to several previous works on the subject. The theory of propagation
3-D Finite Element Electromagnetic and Stress Analyses of the JET LB-SRP Divertor Element (Tungsten Lamella Design)
Yeh, G.T.
1987-08-01T23:59:59.000Z
The 3DFEMWATER model is designed to treat heterogeneous and anisotropic media consisting of as many geologic formations as desired, consider both distributed and point sources/sinks that are spatially and temporally dependent, accept the prescribed initial conditions or obtain them by simulating a steady state version of the system under consideration, deal with a transient head distributed over the Dirichlet boundary, handle time-dependent fluxes due to pressure gradient varying along the Neumann boundary, treat time-dependent total fluxes distributed over the Cauchy boundary, automatically determine variable boundary conditions of evaporation, infiltration, or seepage on the soil-air interface, include the off-diagonal hydraulic conductivity components in the modified Richards equation for dealing with cases when the coordinate system does not coincide with the principal directions of the hydraulic conductivity tensor, give three options for estimating the nonlinear matrix, include two options (successive subregion block iterations and successive point interactions) for solving the linearized matrix equations, automatically reset time step size when boundary conditions or source/sinks change abruptly, and check the mass balance computation over the entire region for every time step. The model is verified with analytical solutions or other numerical models for three examples.
Accelerated finite element elastodynamic simulations using the GPU
Huthwaite, Peter, E-mail: p.huthwaite@imperial.ac.uk
2014-01-15T23:59:59.000Z
An approach is developed to perform explicit time domain finite element simulations of elastodynamic problems on the graphical processing unit, using Nvidia's CUDA. Of critical importance for this problem is the arrangement of nodes in memory, allowing data to be loaded efficiently and minimising communication between the independently executed blocks of threads. The initial stage of memory arrangement is partitioning the mesh; both a well established greedy partitioner and a new, more efficient aligned partitioner are investigated. A method is then developed to efficiently arrange the memory within each partition. The software is applied to three models from the fields of non-destructive testing, vibrations and geophysics, demonstrating a memory bandwidth of very close to the card's maximum, reflecting the bandwidth-limited nature of the algorithm. Comparison with Abaqus, a widely used commercial CPU equivalent, validated the accuracy of the results and demonstrated a speed improvement of around two orders of magnitude. A software package, Pogo, incorporating these developments, is released open source, downloadable from (http://www.pogo-fea.com/) to benefit the community. -- Highlights: A novel memory arrangement approach is discussed for finite elements on the GPU. The mesh is partitioned then nodes are arranged efficiently within each partition. Models from ultrasonics, vibrations and geophysics are run. The code is significantly faster than an equivalent commercial CPU package. Pogo, the new software package, is released open source.
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF
Ozel, Tugrul
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF Ti-6Al-4V ALLOY Turul Manufacturing #12;Transactions of NAMRI/SME 50 Volume 38, 2010 excessive heat generation. Usually above 120 m
PARTIALLY PENALIZED IMMERSED FINITE ELEMENT METHODS ...
2015-01-05T23:59:59.000Z
each interface element, it uses IFE functions constructed with piecewise ...... strate this, we plot errors of a classic bilinear IFE solution and a NPP IFE solution in.
Determination of fracture toughness of AZ31 Mg alloy using the cohesive finite element method
Chen, Long-Qing
Determination of fracture toughness of AZ31 Mg alloy using the cohesive finite element method X Received in revised form 21 June 2012 Accepted 11 August 2012 Keywords: Fracture toughness Cohesive finite is to develop a micromechanical approach for determining the fracture toughness. A phase-field model for grain
Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities
Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Ko, Kwok; /SLAC
2009-03-04T23:59:59.000Z
Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.
A Novel Membrane Finite Element with Drilling Rotations
Kouhia, Reijo
A Novel Membrane Finite Element with Drilling Rotations Reijo Kouhia 1 Abstract. A new low order interpolation is used for the drill rotation #12;eld. Both triangular and quadrilateral elements are considered of freedom. 1 INTRODUCTION In-plane rotational degrees of freedom, \\drilling de- grees of freedom
Experimental and finite element analysis of high pressure packer elements
Berger, Stephanie, 1981-
2004-01-01T23:59:59.000Z
Packer elements are traditionally rubber seals that can operate under specified downhole conditions and provide a seal for either a short-term, retrievable, or a long-term, permanent, completion. In this case a retrievable ...
TOPAZ3D. 3-D Finite Element Heat Transfer
Shapiro, A.B. [Lawrence Livermore National Lab., CA (United States)
1992-02-24T23:59:59.000Z
TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.
Finite element analyses of a linear-accelerator electron gun
Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk, E-mail: muniqbal@ihep.ac.cn [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wasy, A. [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of)] [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)] [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
2014-02-15T23:59:59.000Z
Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000?C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.
Finite element decomposition of the human neocortex
Chow, Seeling
1998-01-01T23:59:59.000Z
dividing boundary types of neuroanatomical consistency . . . . . . . . 5 1 18 Mapping a template onto the object domain. . . . ?53 FIGURE Page 19 Hierarchical division of the human brain into its anatomical parts, . . . 54 20 Decomposition of a... major gyrus into macro elements . ?. , 56 21 Different gyral shapes and their lines of symmetry. . . . 57 22 Mapping gyral line of symmetry at different levels of detail. . . . . . . . 58 23 Sectional view in a human brain atlas. , . . . 60 24...
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01T23:59:59.000Z
The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.
Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint
Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.
2014-01-01T23:59:59.000Z
This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order of magnitude more efficient that low-order finite elements for a given accuracy level. Interpolation of the three-dimensional rotation, a major technical barrier in large-deformation simulation, is discussed in the context of LSFEs. It is shown, by numerical example, that the high-order LSFEs, where weak forms are evaluated with nodal quadrature, do not suffer from a drawback that exists in low-order finite elements where the tangent-stiffness matrix is calculated at the Gauss points. Finally, the new LSFE code is implemented in the new FAST Modularization Framework for dynamic simulation of highly flexible composite-material wind turbine blades. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples showing validation and LSFE performance will be provided in the final paper.
Solar Electric Generating System II finite element analysis
Dohner, J.L.; Anderson, J.R.
1994-04-01T23:59:59.000Z
On June 2, 1992, Landers` earthquake struck the Solar Electric Generating System II, located in Daggett, California. The 30 megawatt power station, operated by the Daggett Leasing Corporation (DLC), suffered substantial damage due to structural failures in the solar farm. These failures consisted of the separation of sliding joints supporting a distribution of parabolic glass mirrors. At separation, the mirrors fell to the ground and broke. It was the desire of the DLC and the Solar Thermal Design Assistance Center (STDAC) of Sandia National Laboratories (SNL) and to redesign these joints so that, in the event of future quakes, costly breakage will be avoided. To accomplish this task, drawings of collector components were developed by the STDAC, from which a detailed finite element computer model of a solar collector was produced. This nonlinear dynamic model, which consisted of over 8,560 degrees of freedom, underwent model reduction to form a low order nonlinear dynamic model containing only 40 degrees of freedom. This model was then used as a design tool to estimate joint dynamics. Using this design tool, joint configurations were modified, and an acceptable joint redesign determined. The results of this analysis showed that the implementation of metal stops welded to support shafts for the purpose of preventing joint separation is a suitable joint redesign. Moreover, it was found that, for quakes of Landers` magnitude, mirror breakage due to enhanced vibration in the trough assembly is unlikely.
Hierarchical strategy for rapid finite element analysis
Varghese, Julian
2004-09-30T23:59:59.000Z
A new methodology is introduced where the natural hierarchical character of model descriptions and simulation results are exploited to expedite analysis of problems. The philosophy and the different concepts involved are illustrated by implementing...
A new finite element lifting surface technique
Kocurek, James David
1973-01-01T23:59:59.000Z
~ ~ ~ ~ ~ ~ ~ ~ ~ 34 VITA 39 vi LIST OF FIGURES Figure Page 1. Planar Panel Idealization 13 2. Vortex-Box Lifting Surface Model 14 3. Vortex-Box Trailing Wake Model 4. Spanwise Distribution Of Circulation, Planar Wing 5. Chordwise Distribution Of Circulation... coordinate ? ~ circulation strength, ft /sec 2 p ~ freestream density, slugs/ft 3 o a portion of S and W velocity potential, ft /sec 2 Subscripts a, b, c points in Cartesian space i, g indicies n ~ direction normal to a surface x, y, z with respect...
Tuminaro, Ray S.
element simulation of strongly coupled fluid flow, heat transfer, and mass transfer with non methods, stabilized finite element methods. 1. INTRODUCTION Modern computational fluid dynamics flows with unstructured mesh finite element methods. These flow problems are characterized by both
Experimental validation of finite element codes for welding deformations
Boyer, Edmond
Experimental validation of finite element codes for welding deformations H. M. Aarbogha,b, , M Institute for Energy Technology, N-2027 Kjeller, Norway. Abstract A single pass Metal Inert Gas welding which numerical codes quantifying welding stresses can be validated. It includes a mov- ing heat source
CONTINUOUSTIME FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY
CONTINUOUSTIME FINITE ELEMENT ANALYSIS OF MULTIPHASE FLOW IN GROUNDWATER HYDROLOGY Zhangxin Chenwater system in groundwater hydrology is given. The system is written in a fractional flow formulation, i for an airwater system in groundwater hydrology, ff = a; w [1], [11], [26]: @(OEae ff s ff ) @t +r \\Delta
Guaranteed Verification of Finite Element Solutions of Heat Conduction
Wang, Delin
2012-07-16T23:59:59.000Z
is invented to estimate the exact error measured in space-time C-norm for both semi-discrete and fully discrete finite element solutions to linear parabolic problem. For a fully discrete solution, a temporal error estimator is also introduced to evaluate...
Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING
Dennis, Brian
arterial supply and effectively blocks the external cooling wave from advancing to the core of the brain1 Dennis, Eberhart, Dulikravich & Radons FINITE ELEMENT SIMULATION OF COOLING OF REALISTIC 3-D Rapid cooling of the brain in the first minutes following the onset of cerebral ischemia
Finite Element Discretization Strategies for the Inverse Electrocardiographic (ECG) Problem
Utah, University of
Finite Element Discretization Strategies for the Inverse Electrocardiographic (ECG) Problem Dafang electrocardiographic (ECG) problems re- quires the ability to both quantify and minimize approxi- mation errors specifically for the inverse ECG prob- lem. By quantitatively analyzing the connection between the ill
Dohrmann, C.R.; Heinstein, M.W.; Jung, J.; Key, S.W.
1999-01-01T23:59:59.000Z
This report documents a collection of papers on a family of uniform strain tetrahedral finite elements and their connection to different element types. Also included in the report are two papers which address the general problem of connecting dissimilar meshes in two and three dimensions. Much of the work presented here was motivated by the development of the tetrahedral element described in the report "A Suitable Low-Order, Eight-Node Tetrahedral Finite Element For Solids," by S. W. Key {ital et al.}, SAND98-0756, March 1998. Two basic issues addressed by the papers are: (1) the performance of alternative tetrahedral elements with uniform strain and enhanced uniform strain formulations, and (2) the proper connection of tetrahedral and other element types when two meshes are "tied" together to represent a single continuous domain.
Bochev, Pavel Blagoveston
2011-06-01T23:59:59.000Z
We develop a new formulation of the Control Volume Finite Element Method (CVFEM) with a multidimensional Scharfetter-Gummel (SG) upwinding for the drift-diffusion equations. The formulation uses standard nodal elements for the concentrations and expands the flux in terms of the lowest-order Nedelec H(curl; {Omega})-compatible finite element basis. The SG formula is applied to the edges of the elements to express the Nedelec element degree of freedom on this edge in terms of the nodal degrees of freedom associated with the endpoints of the edge. The resulting upwind flux incorporates the upwind effects from all edges and is defined at the interior of the element. This allows for accurate evaluation of integrals on the boundaries of the control volumes for arbitrary quadrilateral elements. The new formulation admits efficient implementation through a standard loop over the elements in the mesh followed by loops over the element nodes (associated with control volume fractions in the element) and element edges (associated with flux degrees of freedom). The quantities required for the SG formula can be precomputed and stored for each edge in the mesh for additional efficiency gains. For clarity the details are presented for two-dimensional quadrilateral grids. Extension to other element shapes and three dimensions is straightforward.
Finite size scaling for quantum criticality using the finite-element method
Edwin Antillon; Birgit Wehefritz-Kaufmann; Sabre Kais
2012-03-08T23:59:59.000Z
Finite size scaling for the Schr\\"{o}dinger equation is a systematic approach to calculate the quantum critical parameters for a given Hamiltonian. This approach has been shown to give very accurate results for critical parameters by using a systematic expansion with global basis-type functions. Recently, the finite element method was shown to be a powerful numerical method for ab initio electronic structure calculations with a variable real-space resolution. In this work, we demonstrate how to obtain quantum critical parameters by combining the finite element method (FEM) with finite size scaling (FSS) using different ab initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, internuclear distances, electron density, disorder, lattice structure, and external fields for stability of atomic, molecular systems and quantum phase transitions of extended systems. To illustrate the effectiveness of this approach we provide detailed calculations of applying FEM to approximate solutions for the two-electron atom with varying nuclear charge; these include Hartree-Fock, density functional theory under the local density approximation, and an "exact"' formulation using FEM. We then use the FSS approach to determine its critical nuclear charge for stability; here, the size of the system is related to the number of elements used in the calculations. Results prove to be in good agreement with previous Slater-basis set calculations and demonstrate that it is possible to combine finite size scaling with the finite-element method by using ab initio calculations to obtain quantum critical parameters. The combined approach provides a promising first-principles approach to describe quantum phase transitions for materials and extended systems.
Finite element analysis of controlled laser coagulation experiments
Tolat, Nimish Prabodh
1997-01-01T23:59:59.000Z
, for being my best friend. ABSTRACT TABLE OF CONTENTS Page nt DEDICATION. ACKNOWLEDGMENTS . . TABLE OF CONTENTS. . LIST OF TABLES. LIST OF FIGURES CHAPTER I INTRODUCTION. II THEORETICAL BACKGROUND. 2. 1 The heat diffusion equation 2. 2 How... is the heat generated? 2. 3 Boundary conditions 2. 4 Temperature control 2. 5 Coagulation and thermal damage in biological tissues. . . III METHODOLOGY 3. 1 The finite-element method 3. 2 Element set-up of gel-tissue sample 3. 3 Input variables 3. 4...
Uncoupled thermoelastic structural response by the finite element method
Linn, William Ray
1982-01-01T23:59:59.000Z
Numerical Considerations Banded equation format Newton iteration Finite difference time integration schemes Interpolation of material properties 12 20 21 23 23 24 25 28 33 33 34 34 34 . . 37 39 CODE VERIFICATION Steady-State Heat... element mesh for the transient uniaxial bar with internal heat generation and radiation ~ 71 24 Internal temperatures with time for various values of heat generation 73 25 Surface temperatures with time for various values of heat generation 74 LIST...
Edwards, W.R.; Hoyer, E.H.; Thompson, A.C.
1985-10-01T23:59:59.000Z
The first crystal of the Brown-Hower x-ray monochromator of the LBL-EXXON 54 pole wiggler beamline at Stanford Synchrotron Radiation Laboratory (SSRL) is subjected to intense synchrotron radiation. To provide an accurate thermal/structural analysis of the existing monochromator design, a finite element analysis (FEA) was performed. A very high and extremely localized heat flux is incident on the Si (220) crystal. The crystal, which possesses pronouncedly temperature-dependent orthotropic properties, in combination with the localized heat load, make the analysis ideally suited for finite element techniques. Characterization of the incident synchrotron radiation is discussed, followed by a review of the techniques employed in modeling the monochromator and its thermal/structural boundary conditions. The results of the finite element analysis, three-dimensional temperature distributions, surface displacements and slopes, and stresses, in the area of interest, are presented. Lastly, the effects these results have on monochromator output flux and resolution are examined.
HYDRA, A finite element computational fluid dynamics code: User manual
Christon, M.A.
1995-06-01T23:59:59.000Z
HYDRA is a finite element code which has been developed specifically to attack the class of transient, incompressible, viscous, computational fluid dynamics problems which are predominant in the world which surrounds us. The goal for HYDRA has been to achieve high performance across a spectrum of supercomputer architectures without sacrificing any of the aspects of the finite element method which make it so flexible and permit application to a broad class of problems. As supercomputer algorithms evolve, the continuing development of HYDRA will strive to achieve optimal mappings of the most advanced flow solution algorithms onto supercomputer architectures. HYDRA has drawn upon the many years of finite element expertise constituted by DYNA3D and NIKE3D Certain key architectural ideas from both DYNA3D and NIKE3D have been adopted and further improved to fit the advanced dynamic memory management and data structures implemented in HYDRA. The philosophy for HYDRA is to focus on mapping flow algorithms to computer architectures to try and achieve a high level of performance, rather than just performing a port.
Liquefaction Mapping in Finite-Element Simulations Kirk C. Ellison, S.M.ASCE1
Andrade, Jose
soil liquefaction based on solid mechanical theory rather than empiricism. DOI: 10.1061/ ASCE GT.1943 potentially unstable regions in granular soils at the engineering scale. Example simulations are presented-5606.0000122 CE Database subject headings: Soil liquefaction; Finite element method; Constitutive models
Kaul, Sandeep P.
2004-09-30T23:59:59.000Z
Spontaneous imbibition plays a very important role in the displacement mechanism of non-wetting fluid in naturally fractured reservoirs. We developed a new 2D two-phase finite element numerical model, as available commercial simulators cannot...
E-Print Network 3.0 - advanced finite element Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Mathematics 17 ScienceTheoretical Experimental Summary: Adv. anal. and comp. of turbomachinery Finite Element Methods Architecture: Topics... Brain Computer...
A PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES
Biros, George
A PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES RAHUL S. SAMPATH for the discretized finite element operators and the intergrid transfer operations. The key component of our scheme it has a low setup cost. Key words. Geometric Multigrid, Finite Element Method, Linear Octrees, Adaptive
Visualizing Higher Order Finite Elements: FY05 Yearly Report.
Thompson, David; Pebay, Philippe Pierre
2005-11-01T23:59:59.000Z
This report contains an algorithm for decomposing higher-order finite elementsinto regions appropriate for isosurfacing and proves the conditions under which thealgorithm will terminate. Finite elements are used to create piecewise polynomialapproximants to the solution of partial differential equations for which no analyticalsolution exists. These polynomials represent fields such as pressure, stress, and mo-mentim. In the past, these polynomials have been linear in each parametric coordinate.Each polynomial coefficient must be uniquely determined by a simulation, and thesecoefficients are called degrees of freedom. When there are not enough degrees of free-dom, simulations will typically fail to produce a valid approximation to the solution.Recent work has shown that increasing the number of degrees of freedom by increas-ing the order of the polynomial approximation (instead of increasing the number offinite elements, each of which has its own set of coefficients) can allow some typesof simulations to produce a valid approximation with many fewer degrees of freedomthan increasing the number of finite elements alone. However, once the simulation hasdetermined the values of all the coefficients in a higher-order approximant, tools donot exist for visual inspection of the solution.This report focuses on a technique for the visual inspection of higher-order finiteelement simulation results based on decomposing each finite element into simplicialregions where existing visualization algorithms such as isosurfacing will work. Therequirements of the isosurfacing algorithm are enumerated and related to the placeswhere the partial derivatives of the polynomial become zero. The original isosurfacingalgorithm is then applied to each of these regions in turn.3 AcknowledgementThe authors would like to thank David Day and Louis Romero for their insight into poly-nomial system solvers and the LDRD Senior Council for the opportunity to pursue thisresearch. The authors were supported by the United States Department of Energy, Officeof Defense Programs by the Labratory Directed Research and Development Senior Coun-cil, project 90499. Sandia is a multiprogram laboratory operated by Sandia Corporation,a Lockheed-Martin Company, for the United States Department of Energy under contractDE-AC04-94-AL85000.4
Fracture and Fragmentation of Simplicial Finite Elements Meshes using Graphs
Mota, A; Knap, J; Ortiz, M
2006-10-18T23:59:59.000Z
An approach for the topological representation of simplicial finite element meshes as graphs is presented. It is shown that by using a graph, the topological changes induced by fracture reduce to a few, local kernel operations. The performance of the graph representation is demonstrated and analyzed, using as reference the 3D fracture algorithm by Pandolfi and Ortiz [22]. It is shown that the graph representation initializes in O(N{sub E}{sup 1.1}) time and fractures in O(N{sub I}{sup 1.0}) time, while the reference implementation requires O(N{sub E}{sup 2.1}) time to initialize and O(N{sub I}{sup 1.9}) time to fracture, where NE is the number of elements in the mesh and N{sub I} is the number of interfaces to fracture.
R.H. Saunders GS concrete growth mitigation project instrumentation and finite element analysis
Adeghe, L.; Hindy, A.; Ho, M.S. [Hydroelectric Business Unit, Ontario Hydro, Toronto, Ontario (Canada)
1995-12-31T23:59:59.000Z
In 1991, concrete expansion due to Alkali-Silica Reaction (ASR), was diagnosed as the cause of operational and structural problems at R.H. Saunders Generating Station. Reestablishment of contraction joints between the generating units by cutting slots was initiated in January 1993 to relieve accumulated stresses and allow further expansion without deforming the turbine-generators. An integral part of the remedial measure is the installation of an extensive instrumentation system and development of detailed finite element models of the powerhouse structures. In total, two hundred and thirty five instruments have been installed. The instruments include surface extensometers, borehole extensometers, crackmeters, stressmeters, pendulums, thermocouples, borehole convergence meters and strain gauges. All the instruments are monitored continuously by an Automatic Data Acquisition System (ADAS) which allows instrument data to be evaluated remotely. This instrumentation system is being used to collect data on the structural concrete expansion and response to slot cutting. To complement the instrumentation data, three different finite element models have been developed for use. The models range from a very detailed representation of a single powerhouse unit to a less detailed model of the sixteen-unit powerhouse. The finite element models have been calibrated to reflect measured data and subsequently used to estimate the location and frequency of future cuts.
A Mixed Finite Element Approximation for Compressible Flow of Contamination from Nuclear
Chou, So-Hsiang
A Mixed Finite Element Approximation for Compressible Flow of Contamination from Nuclear Waste in Porous Media S. H. CHOU AND Q. LI Abstract A compressible nuclear waste disposal contamination in porous of this system using a finite element method for the brine, radionuclides, and heat combined with a mixed finite
Manzini, Gianmarco [Los Alamos National Laboratory
2012-07-13T23:59:59.000Z
We develop and analyze a new family of virtual element methods on unstructured polygonal meshes for the diffusion problem in primal form, that use arbitrarily regular discrete spaces V{sub h} {contained_in} C{sup {alpha}} {element_of} N. The degrees of freedom are (a) solution and derivative values of various degree at suitable nodes and (b) solution moments inside polygons. The convergence of the method is proven theoretically and an optimal error estimate is derived. The connection with the Mimetic Finite Difference method is also discussed. Numerical experiments confirm the convergence rate that is expected from the theory.
THE FINITE GROUPS WITH NO REAL p-ELEMENTS SILVIO DOLFI, GUNTER MALLE, AND GABRIEL NAVARRO
Malle, Gunter
THE FINITE GROUPS WITH NO REAL p-ELEMENTS SILVIO DOLFI, GUNTER MALLE, AND GABRIEL NAVARRO Abstract/Generalitat Valenciana. 1 #12;2 SILVIO DOLFI, GUNTER MALLE, AND GABRIEL NAVARRO Theorem D. Let G be a finite group
FINITE ELEMENT ANALYSIS OF BULK TRITIUM SHIPPING PACKAGE
Jordan, J.
2010-06-02T23:59:59.000Z
The Bulk Tritium Shipping Package was designed by Savannah River National Laboratory. This package will be used to transport tritium. As part of the requirements for certification, the package must be shown to meet the scenarios of the Hypothetical Accident Conditions (HAC) defined in Code of Federal Regulations Title 10 Part 71 (10CFR71). The conditions include a sequential 30-foot drop event, 30-foot dynamic crush event, and a 40-inch puncture event. Finite Element analyses were performed to support and expand upon prototype testing. Cases similar to the tests were evaluated. Additional temperatures and orientations were also examined to determine their impact on the results. The peak stress on the package was shown to be acceptable. In addition, the strain on the outer drum as well as the inner containment boundary was shown to be acceptable. In conjunction with the prototype tests, the package was shown to meet its confinement requirements.
Quattrochi, Douglas J. (Douglas John)
2006-01-01T23:59:59.000Z
??Higher order discretizations of the Navier-Stokes equations promise greater accuracy than conventional computational aerodynamics methods. In particular, the discontinuous Galerkin (DG) finite element method has (more)
FINITE ELEMENT METHOD FOR SUBSURFACE HYDROLOGY USING A MIXED EXPLICIT-IMPLICIT SCHEME
Narasimhan, T.N.
2011-01-01T23:59:59.000Z
METHOD FOR SUBSURFACE HYDROLOGY USING A MIXED EXPLICIT-arising in subsurface hydrology. These problems includeFinite Element Method in Hydrology," Int. Jour. Num. Meth.
Reis, A. C.; Moreira Filho, L. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); Menezes, M. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); UNESP - Sao Paulo State University, Ilha Solteira Engineering Faculty, DEM, Av. Brasil, 56 - Centro - Ilha Solteira - SP, CEP 15385-000 (Brazil)
2007-04-07T23:59:59.000Z
The aim of this paper consists in presenting a method of simulating the warpage in 7xxx series aluminium alloy plates. To perform this simulation finite element software MSC.Patran and MSC.Marc were used. Another result of this analysis will be the influence on material residual stresses induced on the raw material during the rolling process upon the warpage of primary aeronautic parts, fabricated through machining (milling) at Embraer. The method used to determinate the aluminium plate residual stress was Layer Removal Test. The numerical algorithm Modified Flavenot Method was used to convert layer removal and beam deflection in stress level. With such information about the level and profile of residual stresses become possible, during the step that anticipate the manufacturing to incorporate these values in the finite-element approach for modelling warpage parts. Based on that warpage parameter surely the products are manufactured with low relative vulnerability propitiating competitiveness and price.
Felice, Maria V. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom and Rolls-Royce plc., Bristol BS34 7QE (United Kingdom); Velichko, Alexander; Wilcox, Paul D. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Barden, Tim J.; Dunhill, Tony K. [Rolls-Royce plc., Bristol BS34 7QE (United Kingdom)
2014-02-18T23:59:59.000Z
A hybrid model to simulate the ultrasonic array response from stress corrosion cracks is presented. These cracks are branched and difficult to detect so the model is required to enable optimization of an array design. An efficient frequency-domain finite element method is described and selected to simulate the ultrasonic scattering. Experimental validation results are presented, followed by an example of the simulated ultrasonic array response from a real stress corrosion crack whose geometry is obtained from an X-ray Computed Tomography image. A simulation-assisted array design methodology, which includes the model and use of real crack geometries, is proposed.
An h-adaptive finite element method for turbulent heat transfer
Carriington, David B [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
A two-equation turbulence closure model (k-{omega}) using an h-adaptive grid technique and finite element method (FEM) has been developed to simulate low Mach flow and heat transfer. These flows are applicable to many flows in engineering and environmental sciences. Of particular interest in the engineering modeling areas are: combustion, solidification, and heat exchanger design. Flows for indoor air quality modeling and atmospheric pollution transport are typical types of environmental flows modeled with this method. The numerical method is based on a hybrid finite element model using an equal-order projection process. The model includes thermal and species transport, localized mesh refinement (h-adaptive) and Petrov-Galerkin weighting for the stabilizing the advection. This work develops the continuum model of a two-equation turbulence closure method. The fractional step solution method is stated along with the h-adaptive grid method (Carrington and Pepper, 2002). Solutions are presented for 2d flow over a backward-facing step.
Implementation of B-splines in a Conventional Finite Element Framework
Owens, Brian C.
2010-01-16T23:59:59.000Z
The use of B-spline interpolation functions in the finite element method (FEM) is not a new subject. B-splines have been utilized in finite elements for many reasons. One reason is the higher continuity of derivatives and smoothness of B...
Finite element solutions of heat transfer in molten polymer flow in tubes with viscous dissipation
Wei, Dongming
Finite element solutions of heat transfer in molten polymer flow in tubes with viscous dissipation the results of finite element analysis of a heat transfer problem of flowing polymer melts in a tubeNusselt problem 1. Introduction Heat transfer to incompressible viscous non-Newto- nian fluids is a problem
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
Finite element simulations of hydrodynamic trapping in microfluidic particle-trap array systems
Nehorai, Arye
Finite element simulations of hydrodynamic trapping in microfluidic particle- trap array systems;Finite element simulations of hydrodynamic trapping in microfluidic particle-trap array systems Xiaoxiao) simulation is a powerful tool in the design and implementation of microfluidic systems, especially
Adaptive finite element methods for PDE-constrained optimal control problems
Adaptive finite element methods for PDE-constrained optimal control problems R. Becker1 , M. Braack is discretized by a finite element Galerkin method. The accuracy of the discretization is controlled by residual of heat transfer, fluid flow and parameter estimation. The contents of this article is as follows
Finite element meshing approached as a global minimization process
WITKOWSKI,WALTER R.; JUNG,JOSEPH; DOHRMANN,CLARK R.; LEUNG,VITUS J.
2000-03-01T23:59:59.000Z
The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested before this project ended. The primary complexity in the extension was in the connectivity problem formulation. Defining all of the interparticle interactions that occur in three-dimensions and expressing them in mathematical relationships is very difficult.
King, Joshua David
2005-02-17T23:59:59.000Z
to simulate CSEM experiments. The objective of the present study is to model the changes in electromagnetic response for a resistive disk and a more geometrically complex structure, which are rough approximations of hydrocarbon reservoirs. The parameters...
Finite element analyses for seismic shear wall international standard problem
Park, Y.J.; Hofmayer, C.H.
1998-04-01T23:59:59.000Z
Two identical reinforced concrete (RC) shear walls, which consist of web, flanges and massive top and bottom slabs, were tested up to ultimate failure under earthquake motions at the Nuclear Power Engineering Corporation`s (NUPEC) Tadotsu Engineering Laboratory, Japan. NUPEC provided the dynamic test results to the OECD (Organization for Economic Cooperation and Development), Nuclear Energy Agency (NEA) for use as an International Standard Problem (ISP). The shear walls were intended to be part of a typical reactor building. One of the major objectives of the Seismic Shear Wall ISP (SSWISP) was to evaluate various seismic analysis methods for concrete structures used for design and seismic margin assessment. It also offered a unique opportunity to assess the state-of-the-art in nonlinear dynamic analysis of reinforced concrete shear wall structures under severe earthquake loadings. As a participant of the SSWISP workshops, Brookhaven National Laboratory (BNL) performed finite element analyses under the sponsorship of the U.S. Nuclear Regulatory Commission (USNRC). Three types of analysis were performed, i.e., monotonic static (push-over), cyclic static and dynamic analyses. Additional monotonic static analyses were performed by two consultants, F. Vecchio of the University of Toronto (UT) and F. Filippou of the University of California at Berkeley (UCB). The analysis results by BNL and the consultants were presented during the second workshop in Yokohama, Japan in 1996. A total of 55 analyses were presented during the workshop by 30 participants from 11 different countries. The major findings on the presented analysis methods, as well as engineering insights regarding the applicability and reliability of the FEM codes are described in detail in this report. 16 refs., 60 figs., 16 tabs.
Higher-order adaptive finite-element methods for KohnSham density functional theory
Motamarri, P. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Nowak, M.R. [Department of Electrical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Electrical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Leiter, K.; Knap, J. [U.S. Army Research Labs, Aberdeen Proving Ground, Aberdeen, MD 21001 (United States)] [U.S. Army Research Labs, Aberdeen Proving Ground, Aberdeen, MD 21001 (United States); Gavini, V., E-mail: vikramg@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)
2013-11-15T23:59:59.000Z
We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of KohnSham 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 GaussLobatto quadrature, and a Chebyshev acceleration technique for computing the occupied eigenspace. The proposed approach has been observed to provide a staggering 100200-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 KohnSham DFT problem. Our studies suggest that staggering computational savingsof the order of 1000-foldrelative 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 KohnSham 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
2010-12-16T23:59:59.000Z
An explicit finite element formulation, used to study the behavior and failure mechanisms of metallic materials under high strain rate loading, is presented. The formulation is based on the assumed-strain approach of Fish and Belytschko [1988], which allows localization bands to be embedded within an element, thereby alleviating mesh sensitivity and reducing the required computational effort. The behavior of the material outside localization bands (and of the virgin material prior to the onset of strain localization) is represented using a Gurson-type coupled plasticity-damage model based on the work of Johnson and Addessio [1988]. Assuming adiabatic conditions, the response of the localization band material is represented by a set of constitutive equations for large elasticviscoplastic deformations in metals at high strain rates and high homologous temperatures (see Brown et al. [1989]). Computational results are compared to experimental data for different metallic alloys to illustrate the advantages of the proposed modeling strategy.
A comparison of spectral element and finite difference methods using statically refined
Ng, Chung-Sang
A comparison of spectral element and finite difference methods using statically refined elements on a refined grid, using spectral method (polynomials of order p). · Accuracy convergence rate refinement dynamically or statically. Why considering spectral element? #12;Motivation · Since the main
LOCAL ENERGY ESTIMATES FOR THE FINITE ELEMENT METHOD ON SHARPLY VARYING GRIDS
Demlow, Alan
. We present local a priori energy estimates that are valid on shape regular grids, an assumption which subdomains under the assumption that the finite element grid is quasi-uniform. Such local energy estimates element theory. Here we prove local energy error estimates under the assumption that the fi- nite element
DIRECT AND INVERSE APPROXIMATION THEOREMS FOR THE p-VERSION OF THE FINITE ELEMENT METHOD IN THE
Guo, Benqi
of the finite element method, for example, MSC/PROBE, FIESTA, MECHANICA, PHLEX, STRESSCHECK, and STRIPE. In 1980
Ward, Karen
Interval Finite Element Methods: New Directions Rafi Muhanna 1 , Vladik Kreinovich 2 , Pavel Ÿ Sol advanced numerical methods to tackle these problems, such as finite element methods (FEM). Lately, new advanced version of these methods have appeared, such as hierarchic higherorder finite element methods (hp
Finite element analysis of blister formation in laser-induced forward transfer
Arnold, Craig B.
, the large film thickness and small thermal diffusivity of the polymer minimize heat diffusion throughARTICLES Finite element analysis of blister formation in laser-induced forward transfer Nicholas T
Quattrochi, Douglas J. (Douglas John)
2006-01-01T23:59:59.000Z
Higher order discretizations of the Navier-Stokes equations promise greater accuracy than conventional computational aerodynamics methods. In particular, the discontinuous Galerkin (DG) finite element method has O(hP+l) ...
Gogineni, Sireesha
2011-10-21T23:59:59.000Z
The ballistic impact of Twaron CT709 plain weave fabrics is studied using an explicit finite element method. Many existing approximations pertaining to woven fabrics cannot adequately represent strain rate-dependent behavior exhibited by the Twaron...
Finite element analysis of flows in secondary settling tanks D. Kleine 1 B. D. Reddy 2
Reddy, Batmanathan Dayanand "Daya"
Finite element analysis of flows in secondary settling tanks D. Kleine 1 B. D. Reddy 2 December 7, 2003 Abstract The equations governing unsteady flows in secondary settling tanks, a component settling tanks, and against results obtained from a finite difference code based on an idealized one
A shear deformable, doubly curved finite element for the analysis of laminated composite structures
Fuehne, Joseph Patrick
2012-06-07T23:59:59.000Z
A SHL'AR DEFORMABLE, DOUBLY CURVED FINITE ELEMENT FOR THE ANALYSIS OF LAMINATED COMPOSITE STRUCTURES A Thesis by JOSEPH PATRICK FUEHNE Submitted to the Graduate College of Texas AE-M University in partial fulfiHment of the requirement... for the degree of MASTER OF SCIENCE May 1988 Major Subject: Mechanical Engineering A SHEAR DEFORMABLE, DOUBLY CURVED FINITE ELEMENT FOR THE ANALYSIS OF LAMINATED COMPOSITE STRUCTURES A Thesis by JOSEPH PATRICK FUEHNE Approved as to style and content by...
Zocher, Marvin Anthony
2012-06-07T23:59:59.000Z
A THREE DIMENSIONAL FINITE ELEMENT CODE FOR THE ANALYSIS OF DAMAGE IN HELICALLY WOUND COMPOSITE CYLINDERS A Thesis MARVIiN AiNTHONY ZOCHER Submitted to the Office of Graduate Studies of Texas Ag:M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1990 Major Subject; Aerospace Engineering A THREE DIMENSIONAL FINITE ELEMENT CODE FOR THE ANALYSIS OF DAMAGE IN HELICALLY WOUND COMPOSITE CYLINDERS A Thesis by i%1ARVIN ANTHONY ZOCHER Approved...
Kondagunta, Veeraraghava Gopal
1993-01-01T23:59:59.000Z
TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA Submitted to the Office of Graduate Studies of Texas ARM University In partial fulffllment... of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject: Aerospace Engineering TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA...
Evaluation of new techniques for two dimensional finite element analysis of woven composites
Gundapaneni, Sitaram Chowdary
1992-01-01T23:59:59.000Z
EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE DECEMBER 1992 Major Subject: Aerospace Engineering EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Approved...
A finite element viscous flow analysis in a radial turbine scroll
Hill, Donald Lee
1987-01-01T23:59:59.000Z
A FINITE ELEMENT VISCOUS FLOW ANALYSIS IN A RADIAL TURBINE SCROLL A Thesis DONALD LEE HILL JR. Submitted to the Graduate College. of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December... 1987 Major Subject: Mechanical Engineering A FINITE ELEMENT VISCOUS FLOW ANALYSIS IN A RADIAL TURBINE SCROLL A Thesis by DONALD LEE HILL JR. Approved as to style snd content by: Dr. Erian A. Baskharone (Chairman of Conunittee) Dr. Alan B azzolo...
Hong, Jung-Wuk, 1970-
2004-01-01T23:59:59.000Z
In this thesis we develop some advances in the method of finite spheres which is a truly meshless numerical technique for the solution of boundary value problems on geometrically complex domains. We present the development ...
Non-periodic finite-element formulation of KohnSham density functional theory
Ortiz, Michael
Non-periodic finite-element formulation of KohnSham density functional theory Phanish-element formulation for KohnSham density functional theory (KS-DFT). We transform the original variational problem, dislocations and crack tips using density functional theory (DFT) at reasonable computational cost by retaining
LOCAL ENERGY ESTIMATES FOR THE FINITE ELEMENT METHOD ON SHARPLY VARYING GRIDS
Guzmán, Johnny
. We present local a priori energy estimates that are valid on shape regular grids, an assumption which subdomains under the assumption that the finite element grid is quasi-uniform. Such local energy estimates. Here we prove local energy error estimates under the assumption that the fi- nite element triangulation
Application of Finite Mixture Models for Vehicle Crash Data Analysis
Park, Byung Jung
2010-07-14T23:59:59.000Z
heterogeneity through the use of finite mixture regression models. A Finite mixture of Poisson or NB regression models is especially useful when the count data were generated from a heterogeneous population. To evaluate these models, Poisson and NB mixture...
Carpenter, D.C.
1998-01-01T23:59:59.000Z
This bibliography provides a list of references on finite element and related methods analysis in reactor physics computations. These references have been published in scientific journals, conference proceedings, technical reports, thesis/dissertations and as chapters in reference books from 1971 to the present. Both English and non-English references are included. All references contained in the bibliography are sorted alphabetically by the first author`s name and a subsort by date of publication. The majority of the references relate to reactor physics analysis using the finite element method. Related topics include the boundary element method, the boundary integral method, and the global element method. All aspects of reactor physics computations relating to these methods are included: diffusion theory, deterministic radiation and neutron transport theory, kinetics, fusion research, particle tracking in finite element grids, and applications. For user convenience, many of the listed references have been categorized. The list of references is not all inclusive. In general, nodal methods were purposely excluded, although a few references do demonstrate characteristics of finite element methodology using nodal methods (usually as a non-conforming element basis). This area could be expanded. The author is aware of several other references (conferences, thesis/dissertations, etc.) that were not able to be independently tracked using available resources and thus were not included in this listing.
Inversion of Robin coefficient by a spectral stochastic finite element approach
Jin Bangti [Department of Mathematics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)], E-mail: kimbtsing@yahoo.com.cn; Zou Jun [Department of Mathematics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)], E-mail: zou@math.cuhk.edu.hk
2008-03-01T23:59:59.000Z
This paper investigates a variational approach to the nonlinear stochastic inverse problem of probabilistically calibrating the Robin coefficient from boundary measurements for the steady-state heat conduction. The problem is formulated into an optimization problem, and mathematical properties relevant to its numerical computations are investigated. The spectral stochastic finite element method using polynomial chaos is utilized for the discretization of the optimization problem, and its convergence is analyzed. The nonlinear conjugate gradient method is derived for the optimization system. Numerical results for several two-dimensional problems are presented to illustrate the accuracy and efficiency of the stochastic finite element method.
Visualization of high resolution, three-dimensional, nonlinear finite element analyses
Christon, M.A.; Spelce, T.E.
1992-03-24T23:59:59.000Z
A two-pass surface extraction algorithm for adaptive finite element meshes is presented in the context of a visualization study for a particle impact and a turbine containment problem. The direct use of finite element data structures for the computation of external surfaces, surface normals, and derived physical quantities is discussed. An overview of the in-betweening algorithm which compensates for rigid body dynamics is presented with a brief discussion of a {open_quotes}direct-to-videodisk{close_quotes} animation strategy.
FINITE ELEMENT SIMULATION OF MACROSCOPIC MACHINING PROCESSES -IMPLEMENTATION OF TIME
Schmidt, Alfred
force and heat flux prediction is triggered that calculates the mechanical and thermal load. It is modeled mathematically by linking heat con- duction equation with the deformation equation on a time with a process model for prediction of cutting forces and heat flux, thermal and mechanical effects during
The Uranium Processing Facility Finite Element Meshing Discussion
Office of Environmental Management (EM)
* Discuss the mesh criteria * Discuss the evolution of the mesh of the UPF main building model * Discuss how the mesh affects the analysis process October 25, 2011 2 Department of...
Hamdallah, Jamil M.
2012-06-07T23:59:59.000Z
For Representing Composite Shell Structures. (May 1987) Jsmil M. Hamdallah, B. S. , University of Toledo Chairman of Advisory Committee: Dr. John J. Engblom A finite element formulation for the analysis of thin to moderately thick lam- inated composite shell... in an analysis if delamination is to be avoided. The results obtained in this research confirm the potential use of the element presented as an accurate and eflicient tool in the analysis of thin to moderately thick laminated shell structures. To my parents...
Nakamachi, Eiji; Yoshida, Takashi; Yamaguchi, Toshihiko; Morita, Yusuke [Dept. of Biomedical Engineering, Doshisha Univ., Kyotanabe, Kyoto, 610-0394 (Japan); Kuramae, Hiroyuki [Dept. of Technol. Management, Osaka Institute of Technol., Asahiku, Osaka, 535-8585 (Japan); Morimoto, Hideo [Furukawa Electric Co. Ltd., Okano, Nishiku, Yokohama, Kanagawa, 220-0073 (Japan)
2014-10-06T23:59:59.000Z
We developed two-scale FE analysis procedure based on the crystallographic homogenization method by considering the hierarchical structure of poly-crystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure can be modeled as a three dimensional representative volume element (RVE). RVE is featured as by 333 eight-nodes solid finite elements, which has 216 crystal orientations. This FE analysis code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro- scales, and further the crystal texture and hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the wire drawing processes by our two-scale FE analysis code under conditions of various drawing angles of dice. We evaluates the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution.
Experimental verification of finite element enhancement and MAC methods
Ibrahim, Syed Azman
1991-01-01T23:59:59.000Z
APPENDIX B APPENDIX C VITA 133 135 139 147 203 LIST OF TABLES Table 1. MAC on Fixed-free Beam Mode Shapes (DOF=10) . . Page 22 2. MAC on Fixed-free Beam Mode Shapes (DOF=100) . 3. MAC on Free-free Beam Mode Shapes (DOF =10) 4. MAC on Free...-free Beam Mode Shapes (DOF = 100) 22 23 23 5. Comparison of Natural Frequencies for Simulated Pipe Model 6. MAC Test Between Berman's Improved and the "Measured" Mode Shapes 36 - Simulated Pipe Model 37 7. MAC Test Between Creamer's Improved...
Finite Element Analysis of Three-Phase Piezoelectric Nanocomposites
Maxwell, Kevin S.
2010-10-12T23:59:59.000Z
on performance. The nanocomposite consisted of a polyimide matrix, beta-CN APB/ODPA, enhanced with single wall carbon nanotubes and PZT-5A particles. The polyimide and nan- otube phases were modeled as a single homogenized phase. This results in a two...
On the role of boundary conditions for CIP stabilization of higher order finite elements
Schieweck, Friedhelm
On the role of boundary conditions for CIP stabilization of higher order finite elements Friedhelm Schieweck 13.11.2007 Abstract We investigate the Continuous Interior Penalty (CIP) stabilization method even in the limit case where the parameter of the CIP stabilization is zero, i.e., where the standard
Bailey, Teresa S
2008-10-10T23:59:59.000Z
of the Piecewise Linear Discontinuous Finite Element Method (PWLD) applied to the particle transport equation in two-dimensional cylindrical (RZ) and three-dimensional Cartesian (XYZ) geometries. We have designed this method to be applicable to radiative... ..................................................... 12 Coupling the radiation transport equation to the Euler equations.. 16 Limit of the radiative transfer equations ........................................ 19 Summary...
Thermo-elasto-plastic finite element analysis of quasi-state processes in Eulerian reference
Michaleris, Panagiotis
Thermo-elasto-plastic finite element analysis of quasi-state processes in Eulerian reference frames Incremental scheme Fine mesh along entire heat source path Lengthy computer runs · Elasto-Plasticity at times ti and ti-1, respectively. Penn State University 5 #12;Elasto-Plasticity Equilibrium: r(r, t) + b
Local Flaps: A Real-Time Finite Element Based Solution to the Plastic Surgery
Liblit, Ben
Local Flaps: A Real-Time Finite Element Based Solution to the Plastic Surgery Defect Puzzle fundamental challenges in plastic surgery is the alter- ation of the geometry and topology of the skin for the patient after the procedure is completed. The plastic surgeon must look at the defect created
Baird, J.A.; Apostal, M.C.; Rotelli, R.L. Jr.; Tinianow, M.A.; Wormley, D.N.
1984-06-01T23:59:59.000Z
The Theoretical Description for the GEODYN interactive finite-element computer program is presented. The program is capable of performing the analysis of the three-dimensional transient dynamic response of a Polycrystalline Diamond Compact Bit-Bit Sub arising from the intermittent contact of the bit with the downhole rock formations. The program accommodates nonlinear, time-dependent, loading and boundary conditions.
California at Berkeley, University of
-Galerkin method and subsequently discretize the resulting equations by N + 1 equally-sized finite elementsDRAFT Chapter 9 HYPERBOLIC DIFFERENTIAL EQUATIONS The classical Bubnov-Galerkin finite element equations. In many problems of mechan- ics and convective heat transfer where convection dominates diffusion
FINITE ELEMENT ANALYSIS OF JNES/NUPEC SEISMIC SHEAR WALL CYCLIC AND SHAKING TABLE TEST DATA.
XU,J.; NIE, J.; HOFMAYER, C.; ALI, S.
2007-04-12T23:59:59.000Z
This paper describes a finite element analysis to predict the JNES/NUPEC cyclic and shaking table RC shear wall test data, as part of a collaborative agreement between the U.S. NRC and JNES to study seismic issues important to the safe operation of commercial nuclear power plant (NPP) structures, systems and components (SSC). The analyses described in this paper were performed using ANACAP reinforced concrete models. The paper describes the ANACAP analysis models and discusses the analysis comparisons with the test data. The ANACAP capability for modeling nonlinear cyclic characteristics of reinforced concrete shear wall structures was confirmed by the close comparisons between the ANACAP analysis results and the JNES/NUPEC cyclic test data. Reasonable agreement between the analysis results and the test data was demonstrated for the hysteresis loops and the shear force orbits, in terms of both the overall shape and the cycle-to-cycle comparisons. The ANACAP simulation analysis of the JNES/NUPEC shaking table test was also performed, which demonstrated that the ANACAP dynamic analysis with concrete material model is able to capture the progressive degrading behavior of the shear wall as indicated from the test data. The ANACAP analysis also predicted the incipient failure of the shear wall, reasonably close to the actual failure declared for the test specimen. In summary, the analyses of the JNES/NUPEC cyclic and shaking table RC shear wall tests presented in this paper have demonstrated the state-of-the-art analysis capability for determining the seismic capacity of RC shear wall structures.
Bajwa, Christopher S.; Piotter, Jason; Cuta, Judith M.; Adkins, Harold E.; Klymyshyn, Nicholas A.; Fort, James A.; Suffield, Sarah R.
2010-08-11T23:59:59.000Z
Storage casks and transportation packages for spent nuclear fuel (SNF) are designed to confine SNF in sealed canisters or casks, provide structural integrity during accidents, and remove decay through a storage or transportation overpack. The transfer, storage, and transportation of SNF in dry storage casks and transport packages is regulated under 10 CFR Part 72 and 10 CFR Part 71, respectively. Finite Element Analysis (FEA) is used with increasing frequency in Safety Analysis Reports and other regulatory technical evaluations related to SNF casks and packages and their associated systems. Advances in computing power have made increasingly sophisticated FEA models more feasible, and as a result, the need for careful review of such models has also increased. This paper identifies best practice recommendations that stem from recent NRC review experience. The scope covers issues common to all commercially available FEA software, and the recommendations are applicable to any FEA software package. Three specific topics are addressed: general FEA practices, issues specific to thermal analyses, and issues specific to structural analyses. General FEA practices covers appropriate documentation of the model and results, which is important for an efficient review process. The thermal analysis best practices are related to cask analysis for steady state conditions and transient scenarios. The structural analysis best practices are related to the analysis of casks and associated payload during standard handling and drop scenarios. The best practices described in this paper are intended to identify FEA modeling issues and provide insights that can help minimize associated uncertainties and errors, in order to facilitate the NRC licensing review process.
Finite element strategies for the efficient analysis and evaluation of solar collector structures
Koteras, J. R.
1980-01-01T23:59:59.000Z
Concentrating or reflecting structures for solar energy systems must be evaluated as to their structural integrity and optical performance. Computer studies can be used as an integral part of these evaluations. The computer studies make use of finite element structural codes coupled with post-processors that calculate optical data. If the analysis of a solar structure is to be carried out in an efficient manner, these computer codes must have certain capabilities. A number of solar energy projects at Sandia National Laboratories have made extensive use of finite element analyses. The analyses have been useful in evaluating design concepts which hold promise for large scale use in solar energy projects. Analysis procedures have been developed for some structures so that evaluations can be carried out in a straightforward manner.
Orth, N.J.; Sansguiri, A.M. [Lamar Univ., Beaumont, TX (United States). Dept. of Mechanical Engineering; Orth, F.J. [Edison Welding Inst., Columbus, OH (United States). Structural Integrity Section
1995-08-01T23:59:59.000Z
It has been proven that the p-version of the finite element method results in a higher accuracy for a given mesh compared to the h-version of the finite element method. This investigation demonstrates the accuracy of the displacement and stress field methods in the vicinity of the crack tip using the p-version of the finite element method to compute the linear elastic stress intensity factor. The stress intensity factor for mode II is computed for an edge crack panel using stress and displacement methods and is compared to the analytical solution.
Visualization methods for high-resolution, transient, 3-D, finite element situations
Christon, M.A.
1995-01-10T23:59:59.000Z
Scientific visualization is the process whereby numerical data is transformed into a visual form to augment the process of discovery and understanding. Visualizing the data generated by large-scale, transient, three-dimensional finite element simulations poses many challenges due to geometric complexity, the presence of multiple materials and multiple element types, and the inherent unstructured nature of the meshes. In this paper, the direct use of finite element data structures, nodal assembly procedures, and element interpolants for volumetric adaptive surface extraction, surface rendering, vector grids and particle tracing is discussed. A brief description of a {open_quotes}direct-to-disk{close_quotes} animation system is presented, and case studies which demonstrate the use of isosurfaces, vector plots, cutting planes, reference surfaces and particle tracing are then discussed in the context of several case studies for transient incompressible viscous flow, and acoustic fluid-structure interaction simulations. An overview of the implications of massively parallel computers on visualization is presented to highlight the issues in parallel visualization methodology, algorithms. data locality and the ultimate requirements for temporary and archival data storage and network bandwidth.
Modeling and Driving Piezoelectric Resonant Blade Elements
for extracting the parameters of the PRB equivalent circuit model: two are direct methods and one is basedrf rjf Figure 3. Equivalent circuit model of the PRB element. Cin is the dielectric capacitance element will bend the van attached to it and the whole structure will vibrate. Optimum operation
Wang, Yaqi
2010-01-16T23:59:59.000Z
In this dissertation, we develop Adaptive Mesh Refinement (AMR) techniques for the steady-state multigroup SN neutron transport equation using a higher-order Discontinuous Galerkin Finite Element Method (DGFEM). We propose two error estimations, a...
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
Numerical solution of 2-D nonlinear inverse heat conduction problems using finite-element techniques
Khachfe, R.A.; Jarny, Y.
2000-02-01T23:59:59.000Z
A general method is presented for solving different classes of nonlinear inverse heat conduction problems (IHCP) for two-dimensional, arbitrarily shaped bodies. It is based on the systematic use of a finite-element library. It is shown that, following this approach, the conjugate gradient method can be easily implemented. The method offers a very wide field of practical applications in inverse thermal analysis, while reducing very significantly the amount of work which remains specific for each particular IHPC. Two numerical experiments illustrate the influence of data errors and the iterative regularization principle.
Large-Scale Parallel Finite Element Analysis of the Stress Singular Problems
Noriyuki Kushida; Hiroshi Okuda; Genki Yagawa [University of Tokyo (Japan)
2002-07-01T23:59:59.000Z
In this paper, the convergence behavior of large-scale parallel finite element method for the stress singular problems was investigated. The convergence behavior of iterative solvers depends on the efficiency of the pre-conditioners. However, efficiency of pre-conditioners may be influenced by the domain decomposition that is necessary for parallel FEM. In this study the following results were obtained: Conjugate gradient method without preconditioning and the diagonal scaling preconditioned conjugate gradient method were not influenced by the domain decomposition as expected. symmetric successive over relaxation method preconditioned conjugate gradient method converged 6% faster as maximum if the stress singular area was contained in one sub-domain. (authors)
Permeability computation on a REV with an immersed finite element method
Laure, P. [Laboratoire J.-A. Dieudonne, CNRS UMR 6621, Universite de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, Cedex 02 (France); Puaux, G.; Silva, L.; Vincent, M. [MINES ParisTech, CEMEF-Centre de Mise en Forme des Materiaux, CNRS UMR 7635, BP 207 1 rue Claude, Daunesse 06904 Sophia Antipolis cedex (France)
2011-05-04T23:59:59.000Z
An efficient method to compute permeability of fibrous media is presented. An immersed domain approach is used to represent the porous material at its microscopic scale and the flow motion is computed with a stabilized mixed finite element method. Therefore the Stokes equation is solved on the whole domain (including solid part) using a penalty method. The accuracy is controlled by refining the mesh around the solid-fluid interface defined by a level set function. Using homogenisation techniques, the permeability of a representative elementary volume (REV) is computed. The computed permeabilities of regular fibre packings are compared to classical analytical relations found in the bibliography.
Determining finite volume elements for the 2D Navier-Stokes equations
Jones, D.A. (California Univ., Irvine, CA (United States). Dept. of Mathematics); Titi, E.S. (California Univ., Irvine, CA (United States). Dept. of Mathematics Cornell Univ., Ithaca, NY (United States). Mathematical Sciences Inst.)
1991-01-01T23:59:59.000Z
We consider the 2D Navier-Stokes equations on a square with periodic boundary conditions. Dividing the square into N equal subsquares, we show that if the asymptotic behavior of the average of solutions on these subsquares (finite volume elements) is known, then the large time behavior of the solution itself is completely determined, provided N is large enough. We also establish a rigorous upper bound for N needed to determine the solutions to the Navier-Stokes equation in terms of the physical parameters of the problem. 34 refs.
Kais, Sabre
initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, and an "exact" formulation using FEM. We then use the FSS approach to determine its critical nuclear chargePHYSICAL REVIEW E 85, 036706 (2012) Finite-size scaling for quantum criticality using the finite
Glass, Micheal W.; Hogan, Roy E., Jr.; Gartling, David K.
2010-03-01T23:59:59.000Z
The need for the engineering analysis of systems in which the transport of thermal energy occurs primarily through a conduction process is a common situation. For all but the simplest geometries and boundary conditions, analytic solutions to heat conduction problems are unavailable, thus forcing the analyst to call upon some type of approximate numerical procedure. A wide variety of numerical packages currently exist for such applications, ranging in sophistication from the large, general purpose, commercial codes, such as COMSOL, COSMOSWorks, ABAQUS and TSS to codes written by individuals for specific problem applications. The original purpose for developing the finite element code described here, COYOTE, was to bridge the gap between the complex commercial codes and the more simplistic, individual application programs. COYOTE was designed to treat most of the standard conduction problems of interest with a user-oriented input structure and format that was easily learned and remembered. Because of its architecture, the code has also proved useful for research in numerical algorithms and development of thermal analysis capabilities. This general philosophy has been retained in the current version of the program, COYOTE, Version 5.0, though the capabilities of the code have been significantly expanded. A major change in the code is its availability on parallel computer architectures and the increase in problem complexity and size that this implies. The present document describes the theoretical and numerical background for the COYOTE program. This volume is intended as a background document for the user's manual. Potential users of COYOTE are encouraged to become familiar with the present report and the simple example analyses reported in before using the program. The theoretical and numerical background for the finite element computer program, COYOTE, is presented in detail. COYOTE is designed for the multi-dimensional analysis of nonlinear heat conduction problems. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in COYOTE are also outlined. Instructions for use of the code are documented in SAND2010-0714.
Finite element analysis of the Arquin-designed CMU wall under a dynamic (blast) load.
Lopez, Carlos; Petti, Jason P.
2008-12-01T23:59:59.000Z
The Arquin Corporation designed a CMU (concrete masonry unit) wall construction and reinforcement technique that includes steel wire and polymer spacers that is intended to facilitate a faster and stronger wall construction. Since the construction method for an Arquin-designed wall is different from current wall construction practices, finite element computer analyses were performed to estimate the ability of the wall to withstand a hypothetical dynamic load, similar to that of a blast from a nearby explosion. The response of the Arquin wall was compared to the response of an idealized standard masonry wall exposed to the same dynamic load. Results from the simulations show that the Arquin wall deformed less than the idealized standard wall under such loading conditions. As part of a different effort, Sandia National Laboratories also looked at the relative static response of the Arquin wall, results that are summarized in a separate SAND Report.
Antoine, Xavier - Institut de Mathématiques ?lie Cartan, Université Henri Poincaré
Keywords: Acoustic scattering Finite element Plane wave Pollution High-frequency Artificial boundary condition in acoustic scattering R. Kechroud a , A. Soulaimani a , X. Antoine b,c,* a ?cole de Technologie are found. Indeed, it is well known that pollution effects [1012] arise in the standard FEM, limiting its
Beaumont, Christopher
SOPALE (a finite-element computer code for the computation of visco-plastic creeping flows are bracketed like this ** 1. What is SOPALE? SOPALE is a computer code written in Fortran 77 which computes of the code history and contributors ** my comments, which may be eliminated or used at your discretion
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
Boyer, Edmond
of steel continuous casting Michel Bellet, Alban Heinrich Ecole des Mines de Paris, Centre de Mise en Forme.bellet@ensmp.fr Synopsis This paper addresses the two-dimensional finite element simulation of steel continuous casting state (temperature, deformation, stresses) of steel all along the continuous casting machine. Both plane
Lopez-Pamies, Oscar
A finite element approach to study cavitation instabilities in non-linear elastic solids under a b s t r a c t This paper proposes an effective numerical method to study cavitation instabilities a single infinitesimal defect at its center. The occurrence of cavitation is identified as the event when
Ewing, Richard E.
A ThreeDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination for transport of nuclearwaste contamination in threedimensional porous media are presented with a description of contamination of groundwater by highlevel nuclear waste and a wide variety of other sources makes a proper
Mofrad, Mohammad R. K.
number mass/heat transport in a fully developed pipe flow. 2002 Elsevier Science B.V. All rights of physics and engineering. Examples are heat transfer processes in rubber extrusion, plastic castingA characteristic/finite element algorithm for time-dependent 3-D advection-dominated transport
X. Frank Xu
2010-03-30T23:59:59.000Z
Multiscale modeling of stochastic systems, or uncertainty quantization of multiscale modeling is becoming an emerging research frontier, with rapidly growing engineering applications in nanotechnology, biotechnology, advanced materials, and geo-systems, etc. While tremendous efforts have been devoted to either stochastic methods or multiscale methods, little combined work had been done on integration of multiscale and stochastic methods, and there was no method formally available to tackle multiscale problems involving uncertainties. By developing an innovative Multiscale Stochastic Finite Element Method (MSFEM), this research has made a ground-breaking contribution to the emerging field of Multiscale Stochastic Modeling (MSM) (Fig 1). The theory of MSFEM basically decomposes a boundary value problem of random microstructure into a slow scale deterministic problem and a fast scale stochastic one. The slow scale problem corresponds to common engineering modeling practices where fine-scale microstructure is approximated by certain effective constitutive constants, which can be solved by using standard numerical solvers. The fast scale problem evaluates fluctuations of local quantities due to random microstructure, which is important for scale-coupling systems and particularly those involving failure mechanisms. The Green-function-based fast-scale solver developed in this research overcomes the curse-of-dimensionality commonly met in conventional approaches, by proposing a random field-based orthogonal expansion approach. The MSFEM formulated in this project paves the way to deliver the first computational tool/software on uncertainty quantification of multiscale systems. The applications of MSFEM on engineering problems will directly enhance our modeling capability on materials science (composite materials, nanostructures), geophysics (porous media, earthquake), biological systems (biological tissues, bones, protein folding). Continuous development of MSFEM will further contribute to the establishment of Multiscale Stochastic Modeling strategy, and thereby potentially to bring paradigm-shifting changes to simulation and modeling of complex systems cutting across multidisciplinary fields.
Quinones, Armando, Sr. (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2008-08-01T23:59:59.000Z
Finite-element analyses were performed to simulate the response of a hypothetical vertical masonry wall subject to different lateral loads with and without continuous horizontal filament ties laid between rows of concrete blocks. A static loading analysis and cost comparison were also performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Simulations of vertical walls subject to static loads representing 100 mph winds (0.2 psi) and a seismic event (0.66 psi) showed that the simulated walls performed similarly and adequately when subject to these loads with and without the ties. Additional simulations and tests are required to assess the performance of actual walls with and without the ties under greater loads and more realistic conditions (e.g., cracks, non-linear response).
Elgeti, Stefanie
2015-01-01T23:59:59.000Z
Fluid flow applications can involve a number of coupled problems. One is the simulation of free-surface flows, which require the solution of a free-boundary problem. Within this problem, the governing equations of fluid flow are coupled with a domain deformation approach. This work reviews five of those approaches: interface tracking using a boundary-conforming mesh and, in the interface capturing context, the level-set method, the volume-of-fluid method, particle methods, as well as the phase-field method. The history of each method is presented in combination with the most recent developments in the field. Particularly, the topics of extended finite elements (XFEM) and NURBS-based methods, such as Isogeometric Analysis (IGA), are addressed. For illustration purposes, two applications have been chosen: two-phase flow involving drops or bubbles and sloshing tanks. The challenges of these applications, such as the geometrically correct representation of the free surface or the incorporation of surface tension ...
Hossain, Mohammad Kabir
1990-01-01T23:59:59.000Z
FINITE ELEMENT ANALYSIS AND DESiGN OF LARGE DIANETER FLEXIBLE VERTICAL PIPES SUBJECTED TO INCREMENTAL COMPACTED BACKFILL LOADS AND CREEP EFFECTS A Thesis by MOHAMMAD KABIR HOSSAIN Submitted to the Office of Graduate Studies of Texas A... BACKFILL LOADS AND CREEP EFFECTS A Thesis by MOHAMMAD KABIR HOSSAIN Approved as to sty1e and content by: R be+r L. Lytton (Chair of Committee) Ozden 0. Ochoa (Member) Derek V. Morris (Member) ames T P Yao (Head of rtment) ABSTRACT Finite...
Test of modified BCS model at finite temperature
V. Yu. Ponomarev; A. I. Vdovin
2005-08-24T23:59:59.000Z
A recently suggested modified BCS (MBCS) model has been studied at finite temperature. We show that this approach does not allow the existence of the normal (non-superfluid) phase at any finite temperature. Other MBCS predictions such as a negative pairing gap, pairing induced by heating in closed-shell nuclei, and ``superfluid -- super-superfluid'' phase transition are discussed also. The MBCS model is tested by comparing with exact solutions for the picket fence model. Here, severe violation of the internal symmetry of the problem is detected. The MBCS equations are found to be inconsistent. The limit of the MBCS applicability has been determined to be far below the ``superfluid -- normal'' phase transition of the conventional FT-BCS, where the model performs worse than the FT-BCS.
One dimensional electroseismic modeling using the finite element ...
2013-01-30T23:59:59.000Z
... and Campanella, O., Characterization of frozen orange juice by ultrasound and wavelet analysis, to appear in Journal of the. Science of Food and Agriculture...
Finite element modeling of SHTE and PSVTM electroseismics
zyserman
(kinetic) energy. The electroseismic equations linking ...... located centered with respect to the x-axis and on the soil surface. The com- putational domain has 3...
Flexible finite-element modeling of global geomagnetic depth sounding
Ribaudo, Joseph Thomas
2011-01-01T23:59:59.000Z
also like to thank Steven Constable, Alexei Kuvshinov, andand Bob Parker and Steven Constable for useful discussions.Randolph E. Bank Steven C. Constable Jeffrey S. Gee Robert
Finite element modeling of SHTE and PSVTM electroseismics
Fabio I. Zyserman
2010-10-07T23:59:59.000Z
Article history: Received 8 January ... partially saturated gas regions are presented. ...... homogeneous layer of water-saturated poorly permeable shale; the.
Finite element modeling of hydraulic fracturing in 3D
2013-03-22T23:59:59.000Z
Mar 22, 2013 ... tion of hydrofracture properties using signals from hydraulic pumps. J. Pet. Sci. ... A.. Touzelet. S.: Tracer testing of the geothermal heat ex-.
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01T23:59:59.000Z
Machines Corporation (IBM). Arduino, P. , Kramer, S. , and2000; Shao and Desai 2000; Arduino et al. 2001). Currently,
Finite element based micromechanical modeling of periodic composite microstructures
Rosario, Matthew J
2010-01-01T23:59:59.000Z
The mechanical behavior of cellular solids, including stiffness and strength, can be tuned by tailoring the underlying geometry and material constituents of the microstructure. Here the effect of key parameters on the ...
Finite-element harmonic experiments to model fractured induced ...
santos
Mar 10, 2014 ... Fractured hydrocarbon reservoirs have been the subject of interest in ...... size. Once a continuous fractal distribution of brine is obtained over...
Finite element modeling of heat and mass transport in aquifers
Grubaugh, Elston Kent
1980-01-01T23:59:59.000Z
1s written as v [ ' ( ? + pg ? )] + 0 = (o + ep a ) ? + ez a ? !I) kxi o ap aT ax, ax; o p at o T at where kx. 1 Po Bp 9T intr1nsic permeab1lity in the x. direct1on, L ; 2. 1 fluid density, M L -2. fluid dynamic v1scos1ty, FTL 2 -l... The basis functions used here are presented in Table 1. These functions fulfill both the compatibility and completeness requirements Linear Nodes le 5r lo Quadratic Nodes 13 I 820 9 I I l7 J Ig ~ I8 l4 19 23 24 Cubic Nodes 37 38 30 39 743...
A Mixed Finite Element Framework for Modeling Coupled Fluid Flow ...
Birendra Jha
2005-10-03T23:59:59.000Z
such as recovery from compaction drive, waterflooding, surface subsidence, seal in- tegrity ...... and for rocks and concrete it is in the range of 0.4-0.6. ...... incorporate into the programs an automatic, self-adaptive, procedure which adjusts.
2-D discrete element modeling of unconsolidated sandstones.
Franquet Barbara, Javier Alejandro
2012-01-01T23:59:59.000Z
??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 (more)
Adaptive Algebraic Multigrid for Finite Element Elliptic Equations with Random Coefficients
Kalchev, D
2012-04-02T23:59:59.000Z
This thesis presents a two-grid algorithm based on Smoothed Aggregation Spectral Element Agglomeration Algebraic Multigrid (SA-{rho}AMGe) combined with adaptation. The aim is to build an efficient solver for the linear systems arising from discretization of second-order elliptic partial differential equations (PDEs) with stochastic coefficients. Examples include PDEs that model subsurface flow with random permeability field. During a Markov Chain Monte Carlo (MCMC) simulation process, that draws PDE coefficient samples from a certain distribution, the PDE coefficients change, hence the resulting linear systems to be solved change. At every such step the system (discretized PDE) needs to be solved and the computed solution used to evaluate some functional(s) of interest that then determine if the coefficient sample is acceptable or not. The MCMC process is hence computationally intensive and requires the solvers used to be efficient and fast. This fact that at every step of MCMC the resulting linear system changes, makes an already existing solver built for the old problem perhaps not as efficient for the problem corresponding to the new sampled coefficient. This motivates the main goal of our study, namely, to adapt an already existing solver to handle the problem (with changed coefficient) with the objective to achieve this goal to be faster and more efficient than building a completely new solver from scratch. Our approach utilizes the local element matrices (for the problem with changed coefficients) to build local problems associated with constructed by the method agglomerated elements (a set of subdomains that cover the given computational domain). We solve a generalized eigenproblem for each set in a subspace spanned by the previous local coarse space (used for the old solver) and a vector, component of the error, that the old solver cannot handle. A portion of the spectrum of these local eigen-problems (corresponding to eigenvalues close to zero) form the coarse basis used to define the new two-level method of our interest. We illustrate the performance of this adaptive two-level procedure with a large set of numerical experiments that demonstrate its efficiency over building the solvers from scratch.
Shadmand, Mohammad
2012-07-16T23:59:59.000Z
A DESIGN-ORIENTED FRAMEWORK TO DETERMINE THE PARASITIC PARAMETERS OF HIGH FREQUENCY MAGNETICS IN SWITCING POWER SUPPLIES USING FINITE ELEMENT ANALYSIS TECHNIQUES A Thesis by MOHAMMAD BAGHER SHADMAND Submitted to the Office... to Determine the Parasitic Parameters of High Frequency Magnetics in Switching Power Supplies using Finite Element Analysis Techniques Copyright 2012 Mohammad Bagher Shadmand A DESIGN-ORIENTED FRAMEWORK TO DETERMINE THE PARASITIC PARAMETERS OF HIGH...
Kim, Beop-Min
2012-06-07T23:59:59.000Z
AN ANALYSIS OF THE EFFECT OF COUPLING BETWEEN TEMPERATURE RISE AND LIGHT DISTRIBUTION IN LASER IRRADIATED TISSUE USING FINITE ELEMENT AND MONTE- CARLO METHODS A Thesis BEOP-MIN KIM Submitted to the Office of Graduate Studies of Texas A... FINITE ELEMENT AND MONTE- CARLO METHODS A Thesis BEOP-MIN KIM Approved as to style and content by: Sohi Rastegar (Chair of Committee) Gerald E. Miller (member) He F. Taylor (member) . Kemble ennett (Head of Department) August 1991 ABSTRACT...
Yaqi Wang; Jean C. Ragusa
2011-10-01T23:59:59.000Z
Diffusion synthetic acceleration (DSA) schemes compatible with adaptive mesh refinement (AMR) grids are derived for the SN transport equations discretized using high-order discontinuous finite elements. These schemes are directly obtained from the discretized transport equations by assuming a linear dependence in angle of the angular flux along with an exact Fick's law and, therefore, are categorized as partially consistent. These schemes are akin to the symmetric interior penalty technique applied to elliptic problems and are all based on a second-order discontinuous finite element discretization of a diffusion equation (as opposed to a mixed or P1 formulation). Therefore, they only have the scalar flux as unknowns. A Fourier analysis has been carried out to determine the convergence properties of the three proposed DSA schemes for various cell optical thicknesses and aspect ratios. Out of the three DSA schemes derived, the modified interior penalty (MIP) scheme is stable and effective for realistic problems, even with distorted elements, but loses effectiveness for some highly heterogeneous configurations. The MIP scheme is also symmetric positive definite and can be solved efficiently with a preconditioned conjugate gradient method. Its implementation in an AMR SN transport code has been performed for both source iteration and GMRes-based transport solves, with polynomial orders up to 4. Numerical results are provided and show good agreement with the Fourier analysis results. Results on AMR grids demonstrate that the cost of DSA can be kept low on locally refined meshes.
Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables
Kumar, Ratnesh
1 Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables for reactive untimed infinite state systems called input- output extended finite automaton (I/O-EFA), which of a finite bisimilar abstraction. The results are illustrated through examples that model reactive software
Peraire, Jaime
Hypersonic Heat Transfer and Anisotropic Visualization with a Higher Order Discontinuous Galerkin;Hypersonic Heat Transfer and Anisotropic Visualization with a Higher Order Discontinuous Galerkin Finite used to predict heat transfer to a cylinder in a hypersonic flow. The strong shock is captured
Incorporation and modification of a shear deformable finite element into MARC
Hofman, Brad Burdell
2012-06-07T23:59:59.000Z
Calculation. Failure Progression Prediction. 2 4 6 8 9 10 QHD40 ELEMENT FUNDAMENTALS . . Review of QHD40 Element Displacement Field. Constitutive Relations. Interlaminar Stresses. 12 12 15 16 TAPER FORMULATION. 20 Taper Capabilities... 42 Cantilevered tapered plate . Page 65 43 Cross-sectional view of tapered laminate 44 Cantilevered plate with Sxg mesh and boundary conditions . . . . . 68 45 Tapered vs. flat plate deflection. . 69 46 Tapered plate transverse displacement. 47...
A MIXED FINITE ELEMENT--FINITE VOLUME FORMULATION OF THE BLACKOIL MODEL #
Bergamaschi, Luca
three independent components (oil, gas, and water) form the three phases (liquid, vapor, and aqua. The two chemical components, oil and gas, represent ideal mean hydrocarbons. At standard pressure and temperature (``stocktank'' conditions or STC), the ``oil'' hydrocarbon will be present in the liquid phase
A finite difference model for free surface gravity drainage
Couri, F.R.; Ramey, H.J. Jr.
1993-09-01T23:59:59.000Z
The unconfined gravity flow of liquid with a free surface into a well is a classical well test problem which has not been well understood by either hydrologists or petroleum engineers. Paradigms have led many authors to treat an incompressible flow as compressible flow to justify the delayed yield behavior of a time-drawdown test. A finite-difference model has been developed to simulate the free surface gravity flow of an unconfined single phase, infinitely large reservoir into a well. The model was verified with experimental results in sandbox models in the literature and with classical methods applied to observation wells in the Groundwater literature. The simulator response was also compared with analytical Theis (1935) and Ramey et al. (1989) approaches for wellbore pressure at late producing times. The seepage face in the sandface and the delayed yield behavior were reproduced by the model considering a small liquid compressibility and incompressible porous medium. The potential buildup (recovery) simulated by the model evidenced a different- phenomenon from the drawdown, contrary to statements found in the Groundwater literature. Graphs of buildup potential vs time, buildup seepage face length vs time, and free surface head and sand bottom head radial profiles evidenced that the liquid refills the desaturating cone as a flat moving surface. The late time pseudo radial behavior was only approached after exaggerated long times.
THE MORTAR FINITE ELEMENT METHOD FOR 3D MAXWELL EQUATIONS: FIRST RESULTS
Buffa, Annalisa
of the mortar element method to the numerical solution of Maxwell's equations (in wave form) by H; accepted for publication (in revised form) February 2, 2001; published electronically July 31, 2001. This work has been partially supported by Istituto di Analisi Numerica del Centro Nazionale delle Ricerche
Finite-difference modeling of commercial aircraft using TSAR
Pennock, S.T.; Poggio, A.J.
1994-11-15T23:59:59.000Z
Future aircraft may have systems controlled by fiber optic cables, to reduce susceptibility to electromagnetic interference. However, the digital systems associated with the fiber optic network could still experience upset due to powerful radio stations, radars, and other electromagnetic sources, with potentially serious consequences. We are modeling the electromagnetic behavior of commercial transport aircraft in support of the NASA Fly-by-Light/Power-by-Wire program, using the TSAR finite-difference time-domain code initially developed for the military. By comparing results obtained from TSAR with data taken on a Boeing 757 at the Air Force Phillips Lab., we hope to show that FDTD codes can serve as an important tool in the design and certification of U.S. commercial aircraft, helping American companies to produce safe, reliable air transportation.
Three-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances
Pasko, Victor
domain (FDTD) model of Schumann resonances (SR) with a set of classical eigenfrequency and quality factorThree-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances, Geophys. Res. Lett., 32
Stricker, C. [Swiss Federal Institute of Technology, Zuerich (Switzerland); Fernando, R.L. [Louisiana State Univ., New Orleans, LA (United States); Elston, R.C. [Univ. of Illinois, Urbana, IL (United States)
1995-12-01T23:59:59.000Z
This paper presents an extension of the finite polygenic mixed model of Fernando et al. to linkage analysis. The finite polygenic mixed model, extended for linkage analysis, leads to a likelihood that can be calculated using efficient algorithms developed for oligogenic models. For comparison, linkage analysis of 5 simulated 4021-member pedigrees was performed using the usual mixed model of inheritance, approximated by Hasstedt, and the finite polygenic mixed model extended for linkage analysis presented here. Maximum likelihood estimates of the finite polygenic mixed model could be inferred to be closer to the simulated values in these pedigrees. 31 refs., 2 tabs.
Lipnikov, Konstantin [Los Alamos National Laboratory; Agouzal, Abdellatif [UNIV DE LYON; Vassilevski, Yuri [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
We present a new technology for generating meshes minimizing the interpolation and discretization errors or their gradients. The key element of this methodology is construction of a space metric from edge-based error estimates. For a mesh with N{sub h} triangles, the error is proportional to N{sub h}{sup -1} and the gradient of error is proportional to N{sub h}{sup -1/2} which are optimal asymptotics. The methodology is verified with numerical experiments.
Constraints of mixing matrix elements in the sequential fourthgeneration model
W. J. Huo
2002-03-23T23:59:59.000Z
We review our works on the sequential fourth generation model and focus on the constriants of $4\\times 4$ quark mixing matrix elements. We investigate the quark mixing matrix elements from the rare $K,B$ meson decays. We talk about the $ hierarchy$ of the $4\\times 4$ matrix and the existence of fourth generation.
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at San Diego Collection: Plasma Physics and Fusion 88 Dynamic Modeling and Simulation with ABACUSS II 28th February 2002 Summary: concerned with predicting the...
Superconvergence of finite element approximations by a computer-based approach
Gangaraj, Srihari Kumar
1994-01-01T23:59:59.000Z
. Superconvcrgence poi?ts I'or I, hc & lass of "harmonic" solutious of the cquatio?s of pla?c elasl i& i ty: Cubi& i& n?dipitv square elements The superconvergence points arc le& atcd at the intersection of thc contours C a?' (P; f, T), i = 1, . . . , 4... of &he mat('ri;&I orl, l&ot ropy. Sup( r(o?v& rgcuce points fol the r& curl]po?eut of thc Ih&s, &I&('u) I'o&. tl&& ?lais of "harmonic" solutions of th&. cquatio? ol' or&i&olropi& h( &I, -&. ond?ction: Cubic serendipity ele&?cnts. /cro-co?to?rs a?d s...
Finite Element Studies in the Out-Of-Plane Failure of Unreinfored Masonry
Martini, Kirk
, modelling phenomena resulting from different elastic properties of block and mortar. · Joints and associated local effects at the block-mortar interface, instead model- ling the mortar joints as potential lines of failure due to cracking. · Joints are smeared out. In this approach, the block-mortar composite
FEAPpv --A Finite Element Analysis Program Personal Version 3.1 User Manual
California at Berkeley, University of
Department of Civil and Environmental Engineering University of California at Berkeley Berkeley, California.1 Execution of FEAPpv and Input/Output Files. . . . . . . . . . . . . . 4 2.2 Modification of Default Options.6 Plasticity Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 7.7 Heat Conduction Material
2-D discrete element modeling of unconsolidated sandstones
Franquet Barbara, Javier Alejandro
2012-06-07T23:59:59.000Z
developed in this thesis is compared to the results of triaxial tests performed in cylindrical core samples of unconsolidated sandstones saturated with heavy oil. The discrete element model treats the sand as a two dimensional assembly of particles...
Extending ballistic graphene FET lumped element models to diffusive devices
Paris-Sud XI, Universit de
Extending ballistic graphene FET lumped element models to diffusive devices G Vincenzi1,2 , G graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced
Varghese, Julian
2010-10-12T23:59:59.000Z
. In addition to implementing an oxidation model, the framework was also used to implement strategies that expedited the simulation of oxidation in textile composites so that it would take only a few hours. The simulation showed that the tow architecture played...
A FINITE ELEMENT APPROACH FOR SIMULATING THE QUENCHING OF LARGE ALUMINIUM COMPRESSOR WHEELS
stresses which result from high temperature gradients. This may influence successive machining steps due as shown in Figure 1. A wheel is made out of one massive billet and is quenched in hot water. A 3D-FE model is challenging due to a variety of reasons, such as requiring material data for large temperature range as well
Cambridge, University of
Finite element simulation of laser spot welding A. De, S. K. Maiti, C. A. Walsh and H. K. D. H laser spot welding, taking into account the temperature dependence of the physical properties and latent formation during laser spot welding, although the `double ellipsoidal' representation requires an a priori
Frey, Pascal
Uzawa conjugate gradient method for the Stokes problem: Matlab implementation with P1-iso-P2/P1 implementation of the Uzawa Conjugate gradient algorithm for the generalized Stokes problem with a P1-iso-P2/P1 for the generalized Stokes problem using the P1-iso-P2/P1 finite element. The Uzawa scheme is a decomposition
Grujicic, Mica
of a fluid-flow control nano-valve M. Grujicica,, G. Caoa, B. Pandurangana, W.N. Royb a Department A finite element method-based procedure is developed for the design of molecularly functionalized nano-size devices. The procedure is aimed at the single-walled carbon nano-tubes (SWCNTs) used in the construction
Finite Element Analysis of Indentation in Fiber-Reinforced Polymer Composites
Ravishankar, Arun
2012-07-16T23:59:59.000Z
indentation tests on the ber of a unidirectional glass/epoxy composite for the strength assessment of its matrix- ber interphase. Their study rested on the assumption that the measured displacement comprises surface indentation and compression components... deformation problem is considered in Chapter II. The indentation load is idealized as a point load. The individual constituents (matrix, in- terphase and ber) of the composite material are modelled as homogeneous, linearly elastic solids whose mechanical...
The inclusion of damage effects in an incremental finite element analysis of composite plates
Kilpatrick, Mark Christopher
1984-01-01T23:59:59.000Z
Buckling Patterns for Unidirectional Composites is available describing damage accumulation (damage history) models. Some assume simple reductions of material matrix properties and/or stiffness reductions [27-29]. These reduce particular material pro..., 2) compressive fiber breakage, 3) tensile matrix cracking, 4) compressive matrix cracking, 5) fiber microbuckling, 6) delamination. The Z. Hashin [39] failure criteria is attractive because it separates the failure of a composite laminate...
Calculation of demagnetization curves of NdFeB-magnets using the finite-element-method
Binner, A.; Roth, S.; Stiller, C. [Inst. fuer Festkoerper- und Werkstofforschung Dresden e.V (Germany)] [Inst. fuer Festkoerper- und Werkstofforschung Dresden e.V (Germany)
1994-03-01T23:59:59.000Z
A method is developed, which allows to investigate the influence of magnetostatic coupling of structural details on the demagnetization curve within a two dimensional model. In contrast to former methods, which assigned to each grain one value of magnetic field and one value of nucleation field only, this method takes into account the spatial distribution of these fields. It considers not only the coupling between adjacent grains but also the effect of distant grains. The nucleation fields along the boundary of the grains are generated by a statistical method. The magnetic field is calculated by FEM.
Mahinthakumar, K.
1997-01-01T23:59:59.000Z
In this report we present parallel solvers for large linear systems arising from the finite-element discretization of the three-dimensional steady-state groundwater flow problem. Our solvers are based on multigrid and Krylov subspace methods. The parallel implementation is based on a domain decomposition strategy with explicit message passing using NX and MPI libraries. We have tested our parallel implementations on the Intel Paragon XP/S 150 supercomputer using up to 1024 parallel processors and on other parallel platforms such as SGI/Power Challenge Array, Cray/SGI Origin 2000, Convex Exemplar SPP-1200, and IBM SP using up to 64 processors. We show that multigrid can be a scalable algorithm on distributed memory machines. We demonstrate the effectiveness of parallel multigrid based solvers by solving problems requiring more than 70 million nodes in less than a minute. This is more than 25 times faster than the diagonal preconditioned conjugate gradient method which is one of the more popular methods for large sparse linear systems. Our results also show that multigrid as a stand alone solver works best for problems with smooth coefficients, but for rough coefficients it is best used as a preconditioner for a Krylov subspace method such as the conjugate gradient method. We show that even for extremely heterogeneous systems the multigrid pre-conditioned conjugate gradient method is at least 10 times faster than the diagonally preconditioned conjugate gradient method.
Quinones, Armando (Arquin Corporation, La Luz, NM); Bibeau, Tiffany A.; Ho, Clifford Kuofei
2006-06-01T23:59:59.000Z
Finite-element analyses were performed to simulate the response of a hypothetical masonry shear wall with and without continuous filament ties to various lateral loads. The loads represented three different scenarios: (1) 100 mph wind, (2) explosive attack, and (3) an earthquake. In addition, a static loading analysis and cost comparison were performed to evaluate optimal materials and designs for the spacers affixed to the filaments. Results showed that polypropylene, ABS, and polyethylene (high density) were suitable materials for the spacers based on performance and cost, and the short T-spacer design was optimal based on its performance and functionality. Results of the shear-wall loading simulations revealed that simulated walls with the continuous filament ties yielded factors of safety that were at least ten times greater than those without the ties. In the explosive attack simulation (100 psi), the simulated wall without the ties failed (minimum factor of safety was less than one), but the simulated wall with the ties yielded a minimum factor of safety greater than one. Simulations of the walls subject to lateral loads caused by 100 mph winds (0.2 psi) and seismic events with a peak ground acceleration of 1 ''g'' (0.66 psi) yielded no failures with or without the ties. Simulations of wall displacement during the seismic scenarios showed that the wall with the ties resulted in a maximum displacement that was 20% less than the wall without the ties.
Discrete-element model for the interaction between ocean waves and sea ice
Xu, Zhijie; Tartakovsky, Alexandre M.; Pan, Wenxiao
2012-01-05T23:59:59.000Z
We present a discrete element method (DEM) model to simulate the mechanical behavior of sea ice in response to ocean waves. The wave/ice interaction can potentially lead to the fracture and fragmentation of sea ice depending on the wave amplitude and period. The fracture behavior of sea ice is explicitly modeled by a DEM method, where sea ice is modeled by densely packed spherical particles with finite size. These particles are bonded together at their contact points through mechanical bonds that can sustain both tensile & compressive forces and moments. Fracturing can be naturally represented by the sequential breaking of mechanical bonds. For a given amplitude and period of incident ocean wave, the model provides information for the spatial distribution and time evolution of stress and micro-fractures and the fragment size distribution. We demonstrate that the fraction of broken bonds,, increases with increasing wave amplitude. In contrast, the ice fragment size decreases with increasing amplitude.
A simple Discrete-Element-Model of Brazilian Test
Sumanta Kundu; Anna Stroisz; Srutarshi Pradhan
2015-03-30T23:59:59.000Z
We present a statistical model which is able to capture some interesting features exhibited in the Brazilian test. The model is based on breakable elements which break when the force experienced by the elements exceed their own load capacity. In this model when an element breaks, the capacity of the neighboring elements are decreased by a certain amount assuming weakening effect around the defected zone. We numerically investigate the stress-strain behavior, the strength of the system, how it scales with the system size and also it's fluctuation for both uniformly and weibull distributed breaking threshold of the elements in the system. We find that the strength of the system approaches it's asymptotic value $\\sigma_c=1/6$ and $\\sigma_c=5/18$ for uniformly and Weibull distributed breaking threshold of the elements respectively. We have also shown the damage profile right at the point when the stress-strain curve reaches at it's maximum and then it is compared with our experimental observations.
Bhardwaj, Rajneesh; Attinger, Daniel
2010-01-01T23:59:59.000Z
The objective of this work is to investigate the coupling of fluid dynamics, heat transfer and mass transfer during the impact and evaporation of droplets on a heated solid substrate. A laser-based thermoreflectance method is used to measure the temperature at the solid-liquid interface, with a time and space resolution of 100 {\\mu}s and 20 {\\mu}m, respectively. Isopropanol droplets with micro- and nanoliter volumes are considered. A finite-element model is used to simulate the transient fluid dynamics and heat transfer during the droplet deposition process, considering the dynamics of wetting as well as Laplace and Marangoni stresses on the liquid-gas boundary. For cases involving evaporation, the diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary condition for the evaporative flux at the droplet-air interface. High-speed visualizations are performed to provide matching parameters for the wetting model used in the simulations. Numerical and experimental results are compar...
Calisch, Samuel Eli
2014-01-01T23:59:59.000Z
Engineering with digital materials, by discretely and reversibly assembling structure and function from a mass-produced construction kit of parts, is indeed an exciting vision. The ability to decouple conventionally linked ...
Reeder, D. Benjamin (Davis Benjamin), 1966-
2002-01-01T23:59:59.000Z
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 ...
Preece, D.S.; Stone, C.M.
1982-08-01T23:59:59.000Z
An increasing interest is being shown worldwide in using leached salt caverns to store oil and natural gas. A critical factor in the use of existing caverns and the design of new ones is the creep behavior of the salt surrounding the caverns. An understanding of this behavior is being gained by using laboratory triaxial creep data as material property input to finite element computer programs designed to calculate displacements and stresses due to creep. An important step in verifying these predictive methods is the comparison of field data from existing caverns with finite element analyses which incorporate the material properties and geometry of each site. This comparison has been made for caverns in the Eminence Dome (Mississippi), West Hackberry Dome (Louisiana), and Bayou Chocktaw Dome (Louisiana) with reasonably good correlation being obtained between measured and predicted volumetric response of the caverns. These comparisons are discussed in this paper.
Rajan, V S P
2006-01-01T23:59:59.000Z
The Scaled Boundary Finite Element Method is a novel semi-analytical method jointly developed by Chongmin Song and John P Wolf to solve problems in elastodynamics and allied problems in civil engineering. This novel method has been recently reformulated for the following categories of problems in electromagnetics: (1) Determination of Eigen values of metallic cavity structures, 2) Full wave analysis of Shielded micro-strip transmission line structures, and Very Large Scale Integrated Circuit (VLSI) interconnects, and 3) Full wave analysis of periodic structures. In this paper, a novel Scaled Boundary Finite Element formulation is developed for the numerical simulation of the time harmonic electromagnetic radiation in free space from metallic structures of arbitrary shape. The development of the novel formulation necessitates the generalization of the familiar Atkinson-Wilcox radiation series expansion so as to be applicable for arbitrary boundary circumscribing the source of radiation.
Model calculations of nuclear data for biologically-important elements
Chadwick, M.B.; Blann, M.; Reffo, G. [Lawrence Livermore National Lab., CA (United States); Young, P.G. [Los Alamos National Lab., NM (United States)
1994-05-01T23:59:59.000Z
We describe calculations of neutron-induced reactions on carbon and oxygen for incident energies up to 70 MeV, the relevant clinical energy in radiation neutron therapy. Our calculations using the FKK-GNASH, GNASH, and ALICE codes are compared with experimental measurements, and their usefulness for modeling reactions on biologically-important elements is assessed.
Biffle, J.H.
1993-02-01T23:59:59.000Z
JAC3D is a three-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equation. The method is implemented in a three-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. An eight-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic-plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere.
Biffle, J.H.; Blanford, M.L.
1994-05-01T23:59:59.000Z
JAC2D is a two-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equations. The method is implemented in a two-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. A four-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic/plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere.
Cheng, Hao
2006-10-30T23:59:59.000Z
sensitivity computation of the streamline models with the versatility of finite-difference simulation was developed. Use of finite-difference simulation can account for complex physics. Finally, we developed an approach to history matching three-phase flow...
Elander, Nils [Department of Physics, Stockholm University, Alba Nova University Center, SE-106 91 Stockholm (Sweden); Levin, Sergey [Department of Physics, Stockholm University, Alba Nova University Center, SE-106 91 Stockholm (Sweden); Institute for Physics, St. Petersburg University, Uljanovskaya 1, St. Petersburg 198904 (Russian Federation); Institute for Theoretical Atomic and Molecular Physics at Harvard University and Smithsonian Astrophysical Observatory, 60 Garden Street, MS 14 Cambridge, Massachusetts 02138 (United States); Yarevsky, Evgeny [Institute for Physics, St. Petersburg University, Uljanovskaya 1, St. Petersburg 198904 (Russian Federation); International Solvay Institutes for Physics and Chemistry, Case Postale 231, Campus Plaine ULB Boulevard du Triomphe, Brussels 1050 (Belgium)
2003-06-01T23:59:59.000Z
A technique based on the total-angular-momentum representation the smooth exterior complex-scaling procedure, and the three-dimensional finite-element method, is applied to calculations of S, P, and D resonant, so-called doubly excited, states of the helium atom. The resonances are calculated with an accuracy better than 10{sup -5} a.u. The applicability of an extrapolation procedure to complex energies is analyzed.
FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA
Taylor, Gary
1 FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA Gareth A.Taylor@brunel.ac.uk ABSTRACT This paper presents the computational modelling of welding phenomena within a versatile numerical) and Computational Solid Mechanics (CSM). With regard to the CFD modelling of the weld pool fluid dynamics, heat
Buscaglia, Gustavo C.
Conservative one-dimensional finite volume discretization of a new cavitation model for piston Cavitation ElrodAdams model Pistonrings a b s t r a c t This paper presents a conservative numerical implementation of a new cavitation model that is well suited for lubrication problems with cavitated regions
Isothermal model of ICF burn with finite alpha range treatment
Galloway, Conner Daniel (Conner Daniel Cross)
2009-01-01T23:59:59.000Z
A simple model for simulating deuterium tritium burn in inertial confinement fusion capsules is developed. The model, called the Isothermal Rarefaction Model, is zero dimensional (represented as ordinary differential ...
Cristofolini, Andrea; Latini, Chiara; Borghi, Carlo A. [Department of Electrical Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna (Italy)
2011-02-01T23:59:59.000Z
This paper presents a technique for improving the convergence rate of a generalized minimum residual (GMRES) algorithm applied for the solution of a algebraic system produced by the discretization of an electrodynamic problem with a tensorial electrical conductivity. The electrodynamic solver considered in this work is a part of a magnetohydrodynamic (MHD) code in the low magnetic Reynolds number approximation. The code has been developed for the analysis of MHD interaction during the re-entry phase of a space vehicle. This application is a promising technique intensively investigated for the shock mitigation and the vehicle control in the higher layers of a planetary atmosphere. The medium in the considered application is a low density plasma, characterized by a tensorial conductivity. This is a result of the behavior of the free electric charges, which tend to drift in a direction perpendicular both to the electric field and to the magnetic field. In the given approximation, the electrodynamics is described by an elliptical partial differential equation, which is solved by means of a finite element approach. The linear system obtained by discretizing the problem is solved by means of a GMRES iterative method with an incomplete LU factorization threshold preconditioning. The convergence of the solver appears to be strongly affected by the tensorial characteristic of the conductivity. In order to deal with this feature, the bandwidth reduction in the coefficient matrix is considered and a novel technique is proposed and discussed. First, the standard reverse Cuthill-McKee (RCM) procedure has been applied to the problem. Then a modification of the RCM procedure (the weighted RCM procedure, WRCM) has been developed. In the last approach, the reordering is performed taking into account the relation between the mesh geometry and the magnetic field direction. In order to investigate the effectiveness of the methods, two cases are considered. The RCM and WRCM procedures has successfully improved the convergence rate of the GMRES solver. For strong anisotropies, the WRCM procedure appears to have a higher convergence rate. The same behavior is shown when applying the methods to the rebuilding of an hypersonic MHD experiment.
Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks
S. Athanassopoulos; E. Mavrommatis; K. A. Gernoth; J. W. Clark
2005-11-30T23:59:59.000Z
A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.
FINITE GROUPS WITH TWO CONJUGACY CLASSES OF p-ELEMENTS AND RELATED QUESTIONS FOR p-BLOCKS
K¨ULSHAMMER, GABRIEL NAVARRO, BENJAMIN SAMBALE, AND PHAM HUU TIEP Abstract. We prove that a finite:01:25 BST Version 2 - Submitted to BLMS #12;2 K¨ULSHAMMER, NAVARRO, SAMBALE, AND TIEP Theorem A can
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys
Beckermann, Christoph
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys KENT of hydrogen in the melt is developed to predict pore formation during the solidification of aluminum alloys by Lee et al.[3] Recent examples of porosity models for aluminum alloy castings, including the effect
Nellie Rajarova,
2010-07-14T23:59:59.000Z
disadvantage of classical variational methods is the difficulty in constructing the approximate functions for arbitrary domains. 1.4. Review of Weighted-Residual Methods Weighted-residual methods are those in which we seek approximate solutions using a... functions. The pth order interpolation function is given by )48.2( 1 2 1 1 2 1 221 2 21 T pp npp p kp g g g f f f...
Meson properties in a nonlocal SU(3) chiral quark model at finite temperature
Contrera, G. A. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Centro Atomico Constituyentes, Buenos Aires (Argentina); Gomez Dumm, D. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)
2010-11-12T23:59:59.000Z
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-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water
Kurganov, Alexander
Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water Alina Chertock of shallow water equations and the pollutant propagation is described by a transport equation. The idea and the pollution computations: the shallow water equations are numerically integrated using a #12;nite- volume
A finite difference model for predicting sediment oxygen demand in streams
Charbonnet, Danielle Andrea
2003-01-01T23:59:59.000Z
in the representative river system using benthic chambers. A finite difference model was developed based on Fick's Law of Diffusion. Mass transfer principles are used to perform a mass balance on the oxygen concentrations in the sediment in order to determine SOD...
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes
Herbin, Raphaèle
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes Emily Gallouët. 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
Finite-temperature order-disorder phase transition in a cluster model of decagonal tilings
Ghler, Franz
phase,2 because its phason degrees of freedom are frozen (locked). The high-temperature state is accordingly called unlocked phase. Here, the thermal energy is suffi- ciently high to excite the phasonFinite-temperature order-disorder phase transition in a cluster model of decagonal tilings Michael
Propagation of Kelvin waves along irregular coastlines in finite-difference models
Propagation of Kelvin waves along irregular coastlines in finite-difference models David J. Schwaba of Kelvin wave phase speed on offshore grid resolution and propagation direction relative to the numerical propagating along a straight coastline; (2) Kelvin wave propagating at a 45 angle to the numerical grid along
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda , Daniel F. Martinb Abstract Continental scale marine ice sheets such as the present day West Antarctic Ice Sheet are strongly phenomenon of this kind is the migration of the grounding line -- the division between ice in contact
Three-dimensional finite difference time domain modeling of the Schumann resonance
Pasko, Victor
Three-dimensional finite difference time domain modeling of the Schumann resonance parameters to as Schumann resonances and are excited by lightning discharges. The detection of such resonances on other frequency propagation is employed to study the Schumann resonance problems on Titan, Venus, and Mars
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION
Eindhoven, Technische Universiteit
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION J. BRUINING AND C.J. VAN DUIJN Abstract. Steam drive recovery of oil is an economical way of producing oil even in times of low oil prices and is used world wide. This paper focuses on the one-dimensional setting, where steam
Thermodynamics and fluctuations of conserved charges in Hadron Resonance Gas model in finite volume
Bhattacharyya, Abhijit; Samanta, Subhasis; Sur, Subrata
2015-01-01T23:59:59.000Z
The thermodynamics of hot and dense matter created in heavy-ion collision experiments are usually studied as a system of infinite volume. Here we report on possible effects for considering a finite system size for such matter in the framework of the Hadron Resonance Gas model. The bulk thermodynamic variables as well as the fluctuations of conserved charges are considered. We find that the finite size effects are insignificant once the observables are scaled with the respective volumes. The only substantial effect is found in the fluctuations of electric charge which may therefore be used to extract information about the volume of fireball created in heavy-ion collision experiments.
Long Fibre Composite Modelling Using Cohesive User's Element
Kozak, Vladislav; Chlup, Zdenek [Institute of Physics of Material AS of the Czech Republic, Zizkova 22, 616 62 Brno (Czech Republic)
2010-09-30T23:59:59.000Z
The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.
Winding Transitions at Finite Energy and Temperature: An O(3) Model
Salman Habib; Emil Mottola; Peter Tinyakov
1996-08-14T23:59:59.000Z
Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at low energies, and numerically for all energies up to the sphaleron scale. The Euclidean period beta of these finite energy instantons increases with energy, contrary to the behavior found in the abelian Higgs model or simple one dimensional systems. This results in a sharp crossover from instanton dominated tunneling to sphaleron dominated thermal activation at a certain critical temperature. Since this behavior is traceable to the soft breaking of conformal invariance by the mass term in the sigma model, semiclassical winding number transition amplitudes in the electroweak theory in 3+1 dimensions should exhibit a similar sharp crossover. We argue that this is indeed the case in the standard model for M_H < 4 M_W.
Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature
Gomez Dumm, D., E-mail: dumm@fisica.unlp.edu.ar [UNLP, IFLP, Departamento de Fisica (Argentina); Contrera, G. A., E-mail: contrera@tandar.cnea.gov.ar [CONICET (Argentina)
2012-06-15T23:59:59.000Z
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.
E-Print Network 3.0 - aeroservoelastic model based Sample Search...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Modeling Figure 1 shows... by coupling the wing finite element model and the aerodynamic model is based on the unsteady Doublet... - TURKEY STRUCTURAL MODELING AND FLUTTER...
Critical analysis of quark-meson coupling models for nuclear matter and finite nuclei
Horst Mueller; Byron K. Jennings
1998-07-09T23:59:59.000Z
Three versions of the quark-meson coupling (QMC) model are applied to describe properties of nuclear matter and finite nuclei. The models differ in the treatment of the bag constant and in terms of nonlinear scalar self-interactions. As a consequence opposite predictions for the medium modifications of the internal nucleon structure arise. After calibrating the model parameters at equilibrium nuclear matter density, binding energies, charge radii, single-particle spectra and density distributions of spherical nuclei are analyzed and compared with QHD calculations. For the models which predict a decreasing size of the nucleon in the nuclear environment, unrealistic features of the nuclear shapes arise.
Building relativistic mean field models for finite nuclei and neutron stars
Wei-Chia Chen; J. Piekarewicz
2014-08-18T23:59:59.000Z
Background: Theoretical approaches based on density functional theory provide the only tractable method to incorporate the wide range of densities and isospin asymmetries required to describe finite nuclei, infinite nuclear matter, and neutron stars. Purpose: A relativistic energy density functional (EDF) is developed to address the complexity of such diverse nuclear systems. Moreover, a statistical perspective is adopted to describe the information content of various physical observables. Methods: We implement the model optimization by minimizing a suitably constructed chi-square objective function using various properties of finite nuclei and neutron stars. The minimization is then supplemented by a covariance analysis that includes both uncertainty estimates and correlation coefficients. Results: A new model, FSUGold2, is created that can well reproduce the ground-state properties of finite nuclei, their monopole response, and that accounts for the maximum neutron star mass observed up to date. In particular, the model predicts both a stiff symmetry energy and a soft equation of state for symmetric nuclear matter--suggesting a fairly large neutron-skin thickness in Pb208 and a moderate value of the nuclear incompressibility. Conclusions: We conclude that without any meaningful constraint on the isovector sector, relativistic EDFs will continue to predict significantly large neutron skins. However, the calibration scheme adopted here is flexible enough to create models with different assumptions on various observables. Such a scheme--properly supplemented by a covariance analysis--provides a powerful tool to identify the critical measurements required to place meaningful constraints on theoretical models.
Bank, Randolph E.
Partial Di#11;erential Equations Randolph E. Bank #3; and Peter K. Jimack y Abstract We present a new domain decomposition algorithm for the parallel #12;nite element solution of elliptic partial di#11 to be utilized in a well load-balanced manner. Finally, numerical evidence is presented which suggests
Notes 01. Modeling of mechanical (lumped parameter) elements
San Andres, Luis
2008-01-01T23:59:59.000Z
Fundamental elements in mechanical systems: inertias, stiffness and damping elements. Equivalent spring coefficients and associated potential energy. Equivalent mass or inertia coefficients and associated kinetic energy. Equations of motion of a...
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
Modeling a solar energy collector with an integrated phase-change material
Guerra, Alexander Adrian
2009-01-01T23:59:59.000Z
In this thesis, a finite-element computer model was created to simulate a solar air heater with an integrated-phase change material. The commercially available finite element package ADINA-Fluid was used to generate the ...
Discrete thermal element modelling of heat conduction in particle systems: Basic formulations
Martin, Ralph R.
methodology, termed the discrete thermal element method (DTEM), for the effec- tive modelling of heat rights reserved. Keywords: Discrete thermal element method; Circular particle; Thermal contact; Heat conduction; Boundary (integral) equation/element 1. Introduction Heat transfer in particle systems can
Paris-Sud XI, Universit de
complex SPF/DB process (involving several sheets partially welded by a diffusion bonding technique prior-like process commonly applied to titanium and aluminum alloys at high temperature and in specific conditions structures. The most common alloys being used are aluminum and titanium alloys. The process consists
A finite element model of grain boundary sliding for nanostructured metals
Jrusalem, Antoine, 1979-
2004-01-01T23:59:59.000Z
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 ...
Finite element 3D Modelling of Mechanical Behaviour of Mineralized Collagen Microfibrils
Boyer, Edmond
) and dehydrated (11). Three-dimensional image reconstructions of 36 nm-diameter corneal collagen fibrils also. Every fiber is formed by a set of fibrils. Each fibril is in turn composed of microfibrils. Finally hierarchical levels to form microfibrils, fibrils and fibers (4-6). The existence of sub-structures in collagen
Geometric simplification of a wooden building connector in dynamic finite element model
Boyer, Edmond
as fonction of elastic modulus along x-axis, Ex , moment of inertia of the cross-section about z-axis, IG of the Eq. 1 leads to the following results in calculating the elastic modulus, Ex as function of frequency eigenvalues determined on the frequency response (cf. Fig. 3), we calculated the values of the elastic modulus
A finite element model of the quasi-three-dimensional viscous flow through airfoil cascades
McArthur, Dwight Roger
1987-01-01T23:59:59.000Z
equation: 1 cl OVs ? ? (rbV, ) + ? = 0 b Bs 88 (4) s ? momentum equation: 1 s Op OV, gV, OVs +ozp+og ~ + s +o4V +usVsyos +ng (5) Re ' Os Bs where: 1 db 1 dr &1 ? + b ds r ds (5u) 1 f 1 dr 1 db't /' 5 ds) (55) Vs (5c) 1 fld2r 1 drdb 1 /dbms 1d...
Finite Element Modeling of Dermally-implanted Enzymatic Microparticle Glucose Sensors
Ali, Saniya
2011-10-21T23:59:59.000Z
recent efforts have focused on the development of optical microscale glucose sensing systems based on the encapsulation of glucose oxidase within microspheres coated with polyelectrolyte multilayer nanofilms. In such sensors, a phosphorescent oxygen...
Ionic Polymer-Metal Composites: Thermodynamical Modeling and Finite Element Solution
Arumugam, Jayavel
2012-10-19T23:59:59.000Z
equations and the transient response of q and C1 are obtained (as shown in appendix A). Mechanical equilibrium equation for the beam is given by EI(v00000 + kC 00 1 ) = w (2.14) along with the natural and essential boundary conditions (EI(v000 + kC1...) M) _v00jx=0 = 0; (EI(v000 + kC1) M) _v00jx=L = 0 (EI(v0000 + kC 0 1) F ) _v0jx=0 = 0; (EI(v0000 + kC 01) F ) _v0jx=L = 0 (2.15) At a given cross section of the beam R _q + S _C1 = V q p DIC1 (2.16) Q _C1 + S _q = EIkv000 (BI + EIk2)C1...
Singh, Dilaver
2015-01-01T23:59:59.000Z
??The prevalence of blast related mild traumatic brain injury (mTBI) in recent military conflicts, attributed in part to an increased exposure to improvised explosive devices (more)
Finite Element Procedures for 2D and 3D Seismoelectric Modeling
Por favor si te parece esto bien, hace el laburo de estimar la constante C8 ya que la necesitamos, quedara seguro en funcion de las cotas de los coeficientes de...
FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE FREQUENCIES
De Flaviis, Franco
Professor Qiao Lin Department of Mechanical Engineering, Columbia University Microelectromechanical systems's Electrical Engineering Department from 1998 to 2000, where he pursued research in microelectromechanical systems (MEMS) and investigated silicon-micromachined fluidic and thermal devices. From 2000 to 2005, he
FINITE ELEMENT MODEL OF MICROELECTROMECHANICAL SYSTEMS SWITCH OPERATING AT MICROWAVE FREQUENCIES
De Flaviis, Franco
1244 JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 14, NO. 6, DECEMBER 2005 Third, Duffing oscillator, intermediate frequency, microelectromechanical systems (MEMS), mixer, non- linear
Shahri, Mehdi Abbaszadeh
2006-04-12T23:59:59.000Z
conditions and are investigated simultaneously to more accurately predict cement failure. The results of this study show the relevant dependency of stress principles with temperature and pressure. These results clarify the deformation caused by any...
Development of a three-dimensional finite element model of a horse's foot
Hanft, Joseph Thomas
1995-01-01T23:59:59.000Z
The horse's foot, defined as the hoof wall and all the structures within it, is subjected to intense load-bearing and energy-absorbing demands. The foot is actually a complex assembly of components that deform as they support loads and absorb energy...
Modeling of three-dimensional viscoelastic flows with free surfaces using a finite element method
Adrian, David Joseph
2010-01-01T23:59:59.000Z
A framework and code have been developed to simulate fiber and film processes; the code can handle three-dimensional, isothermal, incompressible, creeping flow of a Giesekus fluid with free surfaces at infinite capillary ...
. A number of theoretical and empirical models are available to ex- plain the large volume of measured data corresponding author. *N. S. Stoykov is with the Rehabilitation Institute of Chicago, IL 60611 USA, and with the Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL 60611 USA (e-mail: n
FINITE-ELEMENT ANALYSIS OF ROCK FALL ON UNCANISTERED FUEL WASTE PACKAGE DESIGNS (SCPB: N/A)
Z. Ceylan
1996-10-18T23:59:59.000Z
The objective of this analysis is to explore the Uncanistered Fuel (UCF) Tube Design waste package (WP) resistance to rock falls. This analysis will also be used to determine the size of rock that can strike the WP without causing failure in the containment barriers from a height based on the starter tunnel dimensions. The purpose of this analysis is to document the models and methods used in the calculations.
Milind Deo; Chung-Kan Huang; Huabing Wang
2008-08-31T23:59:59.000Z
Black-oil, compositional and thermal simulators have been developed to address different physical processes in reservoir simulation. A number of different types of discretization methods have also been proposed to address issues related to representing the complex reservoir geometry. These methods are more significant for fractured reservoirs where the geometry can be particularly challenging. In this project, a general modular framework for reservoir simulation was developed, wherein the physical models were efficiently decoupled from the discretization methods. This made it possible to couple any discretization method with different physical models. Oil characterization methods are becoming increasingly sophisticated, and it is possible to construct geologically constrained models of faulted/fractured reservoirs. Discrete Fracture Network (DFN) simulation provides the option of performing multiphase calculations on spatially explicit, geologically feasible fracture sets. Multiphase DFN simulations of and sensitivity studies on a wide variety of fracture networks created using fracture creation/simulation programs was undertaken in the first part of this project. This involved creating interfaces to seamlessly convert the fracture characterization information into simulator input, grid the complex geometry, perform the simulations, and analyze and visualize results. Benchmarking and comparison with conventional simulators was also a component of this work. After demonstration of the fact that multiphase simulations can be carried out on complex fracture networks, quantitative effects of the heterogeneity of fracture properties were evaluated. Reservoirs are populated with fractures of several different scales and properties. A multiscale fracture modeling study was undertaken and the effects of heterogeneity and storage on water displacement dynamics in fractured basements were investigated. In gravity-dominated systems, more oil could be recovered at a given pore volume of injection at lower rates. However, if oil production can be continued at high water cuts, the discounted cumulative production usually favors higher production rates. The workflow developed during the project was also used to perform multiphase simulations in heterogeneous, fracture-matrix systems. Compositional and thermal-compositional simulators were developed for fractured reservoirs using the generalized framework. The thermal-compositional simulator was based on a novel 'equation-alignment' approach that helped choose the correct variables to solve depending on the number of phases present and the prescribed component partitioning. The simulators were used in steamflooding and in insitu combustion applications. The framework was constructed to be inherently parallel. The partitioning routines employed in the framework allowed generalized partitioning on highly complex fractured reservoirs and in instances when wells (incorporated in these models as line sources) were divided between two or more processors.
Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay
Horoi, Mihai [Department of Physics, Central Michigan University, Mount Pleasant, Michigan, 48859 (United States)
2013-12-30T23:59:59.000Z
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.
Universal Model of Finite-Reynolds Number Turbulent Flow in Channels and Pipes
Victor S. L'vov; Itamar Procaccia; Oleksii Rudenko
2007-12-07T23:59:59.000Z
In this Letter we suggest a simple and physically transparent analytical model of the pressure driven turbulent wall-bounded flows at high but finite Reynolds numbers Re. The model gives accurate qualitative description of the profiles of the mean-velocity and Reynolds-stresses (second order correlations of velocity fluctuations) throughout the entire channel or pipe in the wide range of Re, using only three Re-independent parameters. The model sheds light on the long-standing controversy between supporters of the century-old log-law theory of von-K\\`arm\\`an and Prandtl and proposers of a newer theory promoting power laws to describe the intermediate region of the mean velocity profile.
Finite Mixture of ARMA-GARCH Model for Stock Price Prediction Him Tang, Kai-Chun Chiu and Lei Xu
Xu, Lei
Finite Mixture of ARMA-GARCH Model for Stock Price Prediction Him Tang, Kai-Chun Chiu and Lei Xu mixture of autore- gressive generalized autoregressive conditional het- eroscedasticity (AR-GARCH) models to extend the mixture of AR-GARCH model (W.C. Wong, F. Yip and L. Xu, 1998) to the mixture of ARMA- GARCH
Plotkin, Steven S.
Correlated energy landscape model for finite, random heteropolymers Steven S. Plotkin, Jin Wang landscape or random energy model REM estimates. A tricritical point is obtained where behavior of the order has been derived from the study of the most rugged energy landscape, the so-called random energy model
Wells, G N
2009-10-28T23:59:59.000Z
compilation of the form parameters.optimize = True # Define boundary of domain class Boundary(SubDomain): def inside(self, x, on_boundary): return on_boundary def solve(mesh, order, model): # Advective velocity V_b = VectorFunctionSpace(mesh, "CG", order+6) b... , V: Constant(V.mesh(), (4.0/5.0, 3.0/5.0)) tmp0 = "(cos((pi*(1+x[0])*(1+x[1])*(1+x[1])/8))*pi*(1+x[1])*(1+x[1])/8)" tmp1 = "(cos((pi*(1+x[0])*(1+x[1])*(1+x[1])/8))*2*pi*(1+x[0])*(1+x[1])/8)" source = "(4.0/5.0)*tmp0 + (3.0/5.0)*tmp1 + 1 + sin((pi*(1+x...
Guerin, P.; Baudron, A. M.; Lautard, J. J. [Commissariat a l'Energie Atomique, DEN/DANS/DM2S/SERMA/LENR, CEA Saclay, 91191 Gif sur Yvette (France)
2006-07-01T23:59:59.000Z
This paper describes a new technique for determining the pin power in heterogeneous core calculations. It is based on a domain decomposition with overlapping sub-domains and a component mode synthesis technique for the global flux determination. Local basis functions are used to span a discrete space that allows fundamental global mode approximation through a Galerkin technique. Two approaches are given to obtain these local basis functions: in the first one (Component Mode Synthesis method), the first few spatial eigenfunctions are computed on each sub-domain, using periodic boundary conditions. In the second one (Factorized Component Mode Synthesis method), only the fundamental mode is computed, and we use a factorization principle for the flux in order to replace the higher order Eigenmodes. These different local spatial functions are extended to the global domain by defining them as zero outside the sub-domain. These methods are well-fitted for heterogeneous core calculations because the spatial interface modes are taken into account in the domain decomposition. Although these methods could be applied to higher order angular approximations - particularly easily to a SPN approximation - the numerical results we provide are obtained using a diffusion model. We show the methods' accuracy for reactor cores loaded with UOX and MOX assemblies, for which standard reconstruction techniques are known to perform poorly. Furthermore, we show that our methods are highly and easily parallelizable. (authors)
The Casimir force on a piston at finite temperature in Randall-Sundrum models
Hongbo Cheng
2011-12-29T23:59:59.000Z
The Casimir effect for a three-parallel-plate system at finite temperature within the frame of five-dimensional Randall-Sundrum models is studied. In the case of Randall-Sundrum model involving two branes we find that the Casimir force depends on the plates distance and temperature after one outer plate has been moved to the distant place. Further we discover that the sign of the reduced force is negative as the plate and piston locate very close, but the reduced force nature becomes repulsive when the plates distance is not very tiny and finally the repulsive force vanishes with extremely large plates separation. The thermal influence causes the repulsive Casimir force greater. Within the frame of one-brane scenario the reduced Casimir force between the piston and one plate left keeps attractive no matter how high the temperature is. It is interesting that the thermal effect leads the attractive Casimir force greater instead of changing the force nature.
Deformable model for 3D intramodal nonrigid breast image registration with fiducial skin markers
of FSM, finite element method (FEM) is used to distribute the markers' displacements linearly over with rigid registration technique. Keywords: Intramodal image registration, finite element method, deformable, we developed a finite element method (FEM) deformable breast model to correct motion artifacts
Dynamical aspects of the plane-wave matrix model at finite temperature
Naoyuki Kawahara; Jun Nishimura; Kentaroh Yoshida
2006-04-25T23:59:59.000Z
We study dynamical aspects of the plane-wave matrix model at finite temperature. One-loop calculation around general classical vacua is performed using the background field method, and the integration over the gauge field moduli is carried out both analytically and numerically. In addition to the trivial vacuum, which corresponds to a single M5-brane at zero temperature, we consider general static fuzzy-sphere type configurations. They are all 1/2 BPS, and hence degenerate at zero temperature due to supersymmetry. This degeneracy is resolved, however, at finite temperature, and we identify the configuration that gives the smallest free energy at each temperature. The Hagedorn transition in each vacuum is studied by using the eigenvalue density method for the gauge field moduli, and the free energy as well as the Polyakov line is obtained analytically near the critical point. This reveals the existence of fuzzy sphere phases, which may correspond to the plasma-ball phases in N=4 SU(\\infty) SYM on S^1 X S^3. We also perform Monte Carlo simulation to integrate over the gauge field moduli. While this confirms the validity of the analytic results near the critical point, it also shows that the trivial vacuum gives the smallest free energy throughout the high temperature regime.
FINITE RATE OF INNOVATION BASED MODELING AND COMPRESSION OF ECG G. Baechler N. Freris R.F. Quick
Dalang, Robert C.
FINITE RATE OF INNOVATION BASED MODELING AND COMPRESSION OF ECG SIGNALS G. Baechler N. Freris R and compress ECG signals. This technique generalizes classical FRI estimation to enable the use of a sum of asym- metric Cauchy-based pulses for modeling electrocardiogram (ECG) signals. We experimentally show
Mixed and Nonconforming Finite Elements
2009-10-28T23:59:59.000Z
Apr 28, 2008 ... tor is then free of over-refinements and satisfies the efficiency and ...... put a c here is to make the error estimator is comparable with the energy.
A NONCONFORMING FINITE ELEMENT METHOD
Karakashian, Ohannes
. Karakashiany and Wadi N. Jureidiniz Abstract. Approximations to solutions of the inhomogeneous boundary value
PERFORMANCE OF A SPECTRAL ELEMENT ATMOSPHERIC MODEL SEAM ON THE HP EXEMPLAR SPP2000.
Baer, Ferdinand
discretization strategy taken from NCAR's Community Climate Model Version 3 (CCM3) [9]. Spectral elements have avoiding clustering points at the poles. Secondly, by using a local coordinate system within each element Fournier for helpful comments. This work was supported in part by the U.S. Department of Energy; Oce
Hyperbolic reformulation of a 1D viscoelastic blood flow model and ADER finite volume schemes
Montecinos, Gino I.; Mller, Lucas O.; Toro, Eleuterio F.
2014-06-01T23:59:59.000Z
The applicability of ADER finite volume methods to solve hyperbolic balance laws with stiff source terms in the context of well-balanced and non-conservative schemes is extended to solve a one-dimensional blood flow model for viscoelastic vessels, reformulated as a hyperbolic system, via a relaxation time. A criterion for selecting relaxation times is found and an empirical convergence rate assessment is carried out to support this result. The proposed methodology is validated by applying it to a network of viscoelastic vessels for which experimental and numerical results are available. The agreement between the results obtained in the present paper and those available in the literature is satisfactory. Key features of the present formulation and numerical methodologies, such as accuracy, efficiency and robustness, are fully discussed in the paper.
Calculation of neutrinoless double decay matrix elements in the Interacting Boson Model
Barea, J. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Unidad Asociada al Departamento de Fisica Atomica, Molecular y Nuclear. Facultad de Fisica, Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain)
2009-11-09T23:59:59.000Z
We show the formalism required to calculate in the Interacting Boson Model the nuclear matrix elements which are necessary in the evaluation of the neutrinoless double beta ({beta}{beta}(0v)) decay half-life.
Pina-Jordan, Jose Gregorio
1985-01-01T23:59:59.000Z
MEASUREMENT AND MODELING OF URANIUM AND STRATEGIC ELEMENT SORPTION BY AMIDOXIME RESINS IN NATURAL SEAMATER A Thesis by JOSE GREGORIO PINA-JORDAN Submitted to the Graduate College oi' Texas A&M University in partial I...'ulfillment of the requirements for the degree of MASTER OP SCIENCE December i985 Major Subject: Nuclear Engineering MEASUREMENT AND MODELING OF URANIUM AND STRATEGIC ELEMENT SORPTION BY AMIDOXIME RESINS IN NATURAL SEANATER A thesis by JOSE GREGORIO PINA...
Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Dumm, D. Gomez [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, Norberto N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, (1078) Buenos Aires (Argentina)
2010-03-01T23:59:59.000Z
We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles and decay constants. The critical temperature is found to be T{sub c{approx_equal}}202 MeV, in better agreement with lattice results than the value recently obtained in the local SU(3) PNJL model. It is seen that above T{sub c} pseudoscalar meson masses get increased, becoming degenerate with the masses of their chiral partners. The temperatures at which this matching occurs depend on the strange quark composition of the corresponding mesons. The topological susceptibility shows a sharp decrease after the chiral transition, signalling the vanishing of the U(1){sub A} anomaly for large temperatures.
Demeio, Lucio
Virtual Laboratories > 12. Finite Sampling Models > 1 2 3 4 5 6 7 8 9 7. The Coupon Collector of a coupon collector: each time the collector buys a certain product (bubble gum or Cracker Jack, for example} In terms of the coupon collector, this random variable gives the number of products required to get k
Abreu, L. M.; Malbouisson, J. M. C. [Instituto de Fisica, Universidade Federal da Bahia, 40210-340, Salvador, BA (Brazil); Malbouisson, A. P. C. [Centro Brasileiro de Pesquisas Fisicas, MCT, 22290-180, Rio de Janeiro, RJ (Brazil)
2011-01-15T23:59:59.000Z
We investigate finite-size effects on the phase structure of chiral and difermion condensates at finite temperature and density in the framework of the two-dimensional large-N Nambu-Jona-Lasinio model. We take into account size-dependent effects by making use of zeta-function and compactification methods. The thermodynamic potential and the gap equations for the chiral and difermion condensed phases are then derived in the mean-field approximation. Size-dependent critical lines separating the different phases are obtained considering antiperiodic boundary conditions for the spatial coordinate.
Finite-size scaling in the quantum phase transition of the open-system Dicke-model
G. Konya; D. Nagy; G. Szirmai; P. Domokos
2012-06-22T23:59:59.000Z
Laser-driven Bose-Einstein condensate of ultracold atoms loaded into a lossy high-finesse optical resonator exhibits critical behavior and, in the thermodynamic limit, a phase transition between stationary states of different symmetries. The system realizes an open-system variant of the celebrated Dicke-model. We study the transition for a finite number of atoms by means of a Hartree-Fock-Bogoliubov method adapted to a damped-driven open system. The finite-size scaling exponents are determined and a clear distinction between the non-equilibrium and the equilibrium quantum criticality is found.
Accurate shell-model nuclear matrix elements for neutrinoless double-beta decay
R. A. Sen'kov; M. Horoi
2014-11-06T23:59:59.000Z
We investigate a novel method of accurate calculation of the neutrinoless double-$\\beta$ decay shell-model nuclear matrix elements for the experimentally relevant case of $^{76}$Ge. We demonstrate that with the new method the nuclear matrix elements have perfect convergence properties and, using only the first 100 intermediate states of each spin, the matrix elements can be calculated with better than 1% accuracy. Based on the analysis of neutrinoless double-beta decays of $^{48}$Ca, $^{82}$Se, and $^{76}$Ge isotopes, we propose a new method to estimate the optimal values of the average closure energies at which the closure approximation gives the most accurate nuclear matrix elements. We also analyze the nuclear matrix elements for the heavy-neutrino-exchange mechanism, and we show that our method can be used to quench contributions from different intermediate spin states.
A graphical preprocessing interface for non-conforming spectral element solvers
Kim, Bo Hung
2009-06-02T23:59:59.000Z
Page 1 Left: Discretization of a square using 50?50 1 st order elements by FEM. Right: Discretizations of a square using 50 th -order single domain with SM... representative numerical technique of this kind is the Finite Element Method (FEM) [2]. It uses small finite number of elements with low order approximation functions (Fig. 1 left). When engineering models have complex geometry, FEM discretizes the geometry (e...
Horoi, Mihai [Department of Physics, Central Michigan University, Mount Pleasant, Michigan, 48859 (United States)
2011-12-16T23:59:59.000Z
Assuming that the neutrinos are Majorana particles and the neutrinoless double beta (0{nu}{beta}{beta}) decay is observed, a reliable 0{nu}{beta}{beta} matrix element is necessary to decide the neutrino mass hierarchy and the minimum neutrino mass. Many nuclear structure techniques, including the shell model, are presently used to calculate these matrix elements. In the last few years one could see a slow convergence of these results, but not yet at a level of 20 several shell model effective interactions and varying other parameters, finding results in a range that spans about 20In this contribution we describe challenges for obtaining reliable shell model 0{nu}{beta}{beta} matrix elements, with emphasis to {sup 76}Ge and {sup 82}Se decays.
Schunk, Peter Randall; Rao, Rekha Ranjana; Chen, Ken Shuang; Labreche, Duane A.; Sun, Amy Cha-Tien; Hopkins, Matthew Morgan; Moffat, Harry K.; Roach, Robert Allen; Hopkins, Polly L.; Notz, Patrick K.; Roberts, Scott Alan; Sackinger, Philip A.; Subia, Samuel Ramirez; Wilkes, Edward Dean; Baer, Thomas A.; Noble, David R.; Secor, Robert B. [3M Engineering Systems and Technology, St. Paul, MN] [3M Engineering Systems and Technology, St. Paul, MN
2013-07-01T23:59:59.000Z
Goma 6.0 is a finite element program which excels in analyses of multiphysical processes, particularly those involving the major branches of mechanics (viz. fluid/solid mechanics, energy transport and chemical species transport). Goma is based on a full-Newton-coupled algorithm which allows for simultaneous solution of the governing principles, making the code ideally suited for problems involving closely coupled bulk mechanics and interfacial phenomena. Example applications include, but are not limited to, coating and polymer processing flows, super-alloy processing, welding/soldering, electrochemical processes, and solid-network or solution film drying. This document serves as a user's guide and reference.
Beyond-the-Standard-Model matrix elements with the gradient flow
A. Shindler; J. de Vries; T. Luu
2014-09-10T23:59:59.000Z
At the Forschungszentrum Juelich (FZJ) we have started a long-term program that aims to determine beyond-the-Standard-Model (BSM) matrix elements using the gradient flow, and to understand the impact of BSM physics in nucleon and nuclear observables. Using the gradient flow, we propose to calculate the QCD component of key beyond the Standard Model (BSM) matrix elements related to quark and strong theta CP violation and the strange content within the nucleon. The former set of matrix elements impacts our understanding of Electric Dipole Moments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while the latter contributes to elastic recoil of Dark Matter particles off nucleons and nuclei. If successful, these results will lay the foundation for extraction of BSM observables from future low-energy, high-intensity and high-accuracy experimental measurements.
A few new (?) facts about infinite elements
2006-04-24T23:59:59.000Z
Keywords: Helmholtz equation; Infinite element; hp finite elements; Echo Area. 1. .... g : ? ouinc on . ?2.1?. The Sommerfeld radiation condition represents a...
Continuum Models of Carbon Nanotube-Based Composites Using the Boundary Element Method
Liu, Yijun
Continuum Models of Carbon Nanotube-Based Composites Using the Boundary Element Method Y.J. Liu)-based composites. Carbon nanotubes, formed conceptually by rolling thin graphite sheets, have been found to be extremely stiff, strong and resilient, and therefore may be ideal for reinforcing composite materials
Building ventilation : a pressure airflow model computer generation and elements of
Paris-Sud XI, Université de
Building ventilation : a pressure airflow model computer generation and elements of validation H Abstract : The calculation of airflows is of great importance for detailed building thermal simulation the building and the outside on one hand, and the different thermal zones on the other. The driving effects
Coupled Model for Heat and Water Transport in a High Level Waste...
Broader source: Energy.gov (indexed) [DOE]
algorithm for mineral dehydration is also applied in the modeling. The Finite Element Heat and Mass transfer code (FEHM) is used to simulate coupled thermal, hydrological, and...
Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Orsaria, M. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Gravitation, Astrophysics and Cosmology Group, FCAyG, UNLP, La Plata (Argentina); Scoccola, N. N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)
2010-09-01T23:59:59.000Z
We study the phase diagram of strongly interacting matter in the framework of a nonlocal SU(2) chiral quark model which includes wave function renormalization and coupling to the Polyakov loop. Both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations are considered. Special attention is paid to the determination of the critical points, both in the chiral limit and at finite quark mass. In particular, we study the position of the critical end point as well as the value of the associated critical exponents for different model parametrizations.
Praveen, E., E-mail: svmstaya@gmail.com; Satyanarayana, S. V. M., E-mail: svmstaya@gmail.com [Department of Physics, Pondicherry University, Puducherry-605014 (India)
2014-04-24T23:59:59.000Z
Traditional definition of phase transition involves an infinitely large system in thermodynamic limit. Finite systems such as biological proteins exhibit cooperative behavior similar to phase transitions. We employ recently discovered analysis of inflection points of microcanonical entropy to estimate the transition temperature of the phase transition in q state Potts model on a finite two dimensional square lattice for q=3 (second order) and q=8 (first order). The difference of energy density of states (DOS) ? ln g(E) = ln g(E+ ?E) ?ln g(E) exhibits a point of inflexion at a value corresponding to inverse transition temperature. This feature is common to systems exhibiting both first as well as second order transitions. While the difference of DOS registers a monotonic variation around the point of inflexion for systems exhibiting second order transition, it has an S-shape with a minimum and maximum around the point of inflexion for the case of first order transition.
T Manos; M Robnik
2015-01-21T23:59:59.000Z
We study the quantum kicked rotator in the classically fully chaotic regime $K=10$ and for various values of the quantum parameter $k$ using Izrailev's $N$-dimensional model for various $N \\le 3000$, which in the limit $N \\rightarrow \\infty$ tends to the exact quantized kicked rotator. By numerically calculating the eigenfunctions in the basis of the angular momentum we find that the localization length ${\\cal L}$ for fixed parameter values has a certain distribution, in fact its inverse is Gaussian distributed, in analogy and in connection with the distribution of finite time Lyapunov exponents of Hamilton systems. However, unlike the case of the finite time Lyapunov exponents, this distribution is found to be independent of $N$, and thus survives the limit $N=\\infty$. This is different from the tight-binding model of Anderson localization. The reason is that the finite bandwidth approximation of the underlying Hamilton dynamical system in the Shepelyansky picture (D.L. Shepelyansky, {\\em Phys. Rev. Lett.} {\\bf 56}, 677 (1986)) does not apply rigorously. This observation explains the strong fluctuations in the scaling laws of the kicked rotator, such as e.g. the entropy localization measure as a function of the scaling parameter $\\Lambda={\\cal L}/N$, where $\\cal L$ is the theoretical value of the localization length in the semiclassical approximation. These results call for a more refined theory of the localization length in the quantum kicked rotator and in similar Floquet systems, where we must predict not only the mean value of the inverse of the localization length $\\cal L$ but also its (Gaussian) distribution, in particular the variance. In order to complete our studies we numerically analyze the related behavior of finite time Lyapunov exponents in the standard map and of the 2$\\times$2 transfer matrix formalism. This paper is extending our recent work.
Davidson, Timothy Ross
1994-01-01T23:59:59.000Z
regionally corresponds with the northern limit of the Paleozoic carbonates, at the contact of the Eleana Formation, a Paleozoic aquitard. This study investigates, using finite difference modeling, the relationship between the steep hydraulic gradient...
Yu-Kui Zhou
1995-06-08T23:59:59.000Z
The fused six-vertex models with open boundary conditions are studied. The Bethe ansatz solution given by Sklyanin has been generalized to the transfer matrices of the fused models. We have shown that the eigenvalues of transfer matrices satisfy a group of functional relations, which are the $su$(2) fusion rule held by the transfer matrices of the fused models. The fused transfer matrices form a commuting family and also commute with the quantum group $U_q[sl(2)]$. In the case of the parameter $q^h=-1$ ($h=4,5,\\cdots$) the functional relations in the limit of spectral parameter $u\\to \\i\\infty$ are truncated. This shows that the $su$(2) fusion rule with finite level appears for the six vertex model with the open boundary conditions. We have solved the functional relations to obtain the finite-size corrections of the fused transfer matrices for low-lying excitations. From the corrections the central charges and conformal weights of underlying conformal field theory are extracted. To see different boundary conditions we also have studied the six-vertex model with a twisted boundary condition.
Karl-Ludwig Kratz; Khalil Farouqi; Peter Mller
2014-06-10T23:59:59.000Z
Theoretical studies of the nucleosynthesis origin of the heavy elements in our Solar System (S.S.) by the rapid neutron-capture process (r-process) still face the entwined uncertainties in the possible astrophysical scenarios and the nuclear-physics properties far from stability. In this paper we present results from the investigation of an r-process in the high-entropy wind (HEW) of core-collapse supernovae (here chosen as one of the possible scenarios for this nucleosynthesis process), using new nuclear-data input calculated in a consistent approach, for masses and $\\beta$-decay properties from the new finite-range droplet model FRDM(2012). The accuracy of the new mass model is 0.56 MeV with respect to {\\sc AME2003}, to which it was adjusted. We compare the new HEW r-process abundance pattern to the latest S.S. r-process residuals and to our earlier calculations with the nuclear-structure quantities based on FRDM(1992). Substantial overall and specific local improvements in the calculated pattern of the r-process between $A\\simeq 110$ and $^{209}$Bi, as well as remaining deficiencies are discussed in terms of the underlying spherical and deformed shell structure far from stability.
Influence of heavy element and rotationally induced diffusions on the solar models
M. Gabriel
1997-06-20T23:59:59.000Z
We present the results of solar model computation done with the latest Livermore opacities. Models without diffusion, with hydrogen diffusion only and with hydrogen and heavy elements diffusion are considered. The influence of mixing below the convective envelope induced by rotation and angular momentum losses is also discussed. The sound speed of our best model, does not deviate from that of Basu's seismic one by more than about one thousandth; p-mode frequencies are also compared with observations and frequencies for low order p and g-modes are given.
Shouchun Deng; Robert Podgorney; Hai Huang
2011-02-01T23:59:59.000Z
Key challenges associated with the EGS reservoir development include the ability to reliably predict hydraulic fracturing and the deformation of natural fractures as well as estimating permeability evolution of the fracture network with time. We have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a network flow model. In DEM model, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external and internal load is applied. The natural fractures are represented by a series of connected line segments. Mechanical bonds that intersect with such line segments are removed from the DEM model. A network flow model using conjugate lattice to the DEM network is developed and coupled with the DEM. The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms the mechanical bonds and breaks them if the deformation reaches a prescribed threshold value. Such deformation/fracturing in turn changes the permeability of the flow network, which again changes the evolution of fluid pressure, intimately coupling the two processes. The intimate coupling between fracturing/deformation of fracture networks and fluid flow makes the meso-scale DEM- network flow simulations necessary in order to accurately evaluate the permeability evolution, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed. Methodology for coupling the DEM model with continuum flow and heat transport models will also be discussed.
Hiroaki Kohyama
2008-04-30T23:59:59.000Z
We construct the phase diagram of the chiral and diquark condensates at finite temperature and density in the 1+1 dimensional (2D) two flavor massless Gross Neveu model. The resultant phase diagram shows (I) the chiral condensed phase at low temperature and density, (II) the diquark condensed phase at low temperature and high density, and (III) the chiral and diquark coexisting phase at low temperature and intermediate density. This phase structure is also seen in the 3D Gross Neveu model and the 4D Nambu Jona-Lasinio (NJL) model. Thus the phase diagrams of the chiral and diquark condensates in the NJL-type models do not change qualitatively in 2D, 3D and 4D.
Torres-Verdín, Carlos
-element method (FEM) to simulate wireline (WL) borehole acoustic waveforms. It works in the frequency domain of the components can be consid- ered as an acoustic fluid (A) or a linear elastic/viscoelastic solid (E). Wave of the pressure in a fluid, u(x,n) is a Fourier transform of the displacement in a solid, ¯p and ¯u
Luo, Xiaoyu
Journal of Biomechanics 34 (2001) 12791289 A nonlinear anisotropic model for porcine aortic heart finite element model for porcine heart valves. The model is based on the uniaxial experimental data of porcine aortic heart valve leaflet and the properties of nonlinear composite material. A finite element
Energy Landscape of the Finite-Size Mean-field 2-Spin Spherical Model and Topology Trivialization
Dhagash Mehta; Jonathan D. Hauenstein; Matthew Niemerg; Nicholas J. Simm; Daniel A. Stariolo
2014-09-29T23:59:59.000Z
Motivated by the recently observed phenomenon of topology trivialization of potential energy landscapes (PELs) for several statistical mechanics models, we perform a numerical study of the finite size $2$-spin spherical model using both numerical polynomial homotopy continuation and a reformulation via non-hermitian matrices. The continuation approach computes all of the complex stationary points of this model while the matrix approach computes the real stationary points. Using these methods, we compute the average number of stationary points while changing the topology of the PEL as well as the variance. Histograms of these stationary points are presented along with an analysis regarding the complex stationary points. This work connects topology trivialization to two different branches of mathematics: algebraic geometry and catastrophe theory, which is fertile ground for further interdisciplinary research.
Analysis and behavioral modeling of the Finite State Machines of the Xpress Transfer Protocol
Madduri, Venkateswara Rao
1994-01-01T23:59:59.000Z
OF THE 3. 4 SPECIFICATION OF THE XTP FINITE STATE MACHINES . A. XTP Context Manager State Machine B. XTP Output State Machine C. XTP Sync State Machine. D. XTP Rate Control State Machine E. XTP Control-Send State Machine. . . F. XTP Input State... control parameters 26 II XTP context manager state transition table[12]. III XTP output state machine transition table [12]. IV XTP sync state machine transition table[12]. 40 V XTP rate control state machine transition table[12]. VI XTP control...
Modeling and simulation for a PEM fuel cell with catalyst layers in finite thickness.
Yin, Jianghui (Author)
2007-01-01T23:59:59.000Z
??A detailed non-isothermal computational fluid dynamics (CFD) model for proton electrolyte membrane (PEM) fuel cells is developed in this thesis. This model consists of the (more)
Goudon, Thierry, E-mail: thierry.goudon@inria.fr [Team COFFEE, INRIA Sophia Antipolis Mediterranee (France) [Team COFFEE, INRIA Sophia Antipolis Mediterranee (France); Labo. J.A. Dieudonne CNRS and Univ. Nice-Sophia Antipolis (UMR 7351), Parc Valrose, 06108 Nice cedex 02 (France); Parisot, Martin, E-mail: martin.parisot@gmail.com [Project-Team SIMPAF, INRIA Lille Nord Europe, Park Plazza, 40 avenue Halley, F-59650 Villeneuve d'Ascq cedex (France)] [Project-Team SIMPAF, INRIA Lille Nord Europe, Park Plazza, 40 avenue Halley, F-59650 Villeneuve d'Ascq cedex (France)
2012-10-15T23:59:59.000Z
In the so-called Spitzer-Haerm regime, equations of plasma physics reduce to a nonlinear parabolic equation for the electronic temperature. Coming back to the derivation of this limiting equation through hydrodynamic regime arguments, one is led to construct a hierarchy of models where the heat fluxes are defined through a non-local relation which can be reinterpreted as well by introducing coupled diffusion equations. We address the question of designing numerical methods to simulate these equations. The basic requirement for the scheme is to be asymptotically consistent with the Spitzer-Haerm regime. Furthermore, the constraints of physically realistic simulations make the use of unstructured meshes unavoidable. We develop a Finite Volume scheme, based on Vertex-Based discretization, which reaches these objectives. We discuss on numerical grounds the efficiency of the method, and the ability of the generalized models in capturing relevant phenomena missed by the asymptotic problem.
Mukherjee, Souvik
2010-10-12T23:59:59.000Z
ordnance, is often highly conductive and magnetically permeable. Interpretation of the CSEM response in the presence of cultural noise requires an understanding of electromagnetic field diffusion and the effects of anomalous highly conductive and permeable...
Alternative Least-Squares Finite Element Models of Navier-Stokes Equations for Power-Law Fluids
Vallala, Venkat
2010-01-16T23:59:59.000Z
. The first variation in two-dimensions can be expressed as: 19 (, , ) 0 e uv u v IVf f u u v vd xy x y x x y y ?? ? ?? ? ?? ?? ? ? ? ?? ???? ?????? ? ? ? ? ? ? ??? ? =????? +? ?+? ? ?= ?????? ??????? ? ?? ? ? ? ? ? ? ??? ? ???? ???? ?? ? (2.11) where... ( , )uv are the horizontal...
Firoozabadi, Abbas
and gravitational fingering that can negatively affect hydrocarbon (HC) recovery, or aid carbon sequestration and other simulators. The examples consider gravitational fingering during CO2 sequestration in aquifers could have a significant impact on CO2 sequestration and IOR. Accurate simulation of compositional
Mueller, Pablo Federico
2009-01-01T23:59:59.000Z
??In this work we have studied brittle fracture in high-chromium reduced activation tempered martensitic steels foreseen as structural materials for thermonuclear fusion reactors. Developing the (more)
Cambridge, University of
be written in matrix form as f = kd F1 F2 = k -k -k k 1 2 System of Two Springs Fig. 1c shows a system be written as F = KD F1 F2 F3 = k1 -k1 0 -k1 k1 + k2 -k2 0 -k2 k2 1 2 3 The overall stiffness
Pontaza, Juan Pablo
2004-09-30T23:59:59.000Z
of the weak form Galerkin procedure to problems whose solutions can be characterized as global minimizers results in global minimiza- tion of quadratic functionals, such is the case for linear elasticity problems; see [93]. In this case, given a conforming... and the success of the method for linear elasticity problems led to early attempts to extend weak form Galerkin formulations beyond problems whose solutions could be characterized as unconstrained global minimizers. For example, problems of the saddle-point type...
Liu, Yueqiang, E-mail: yueqiang.liu@ccfe.ac.uk; Chapman, I. T. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Graves, J. P. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, 1015 Lausanne (Switzerland)] [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, 1015 Lausanne (Switzerland); Hao, G. Z. [Southwestern Institute of Physics, PO Box 432, Chengdu 610041 (China)] [Southwestern Institute of Physics, PO Box 432, Chengdu 610041 (China); Wang, Z. R.; Menard, J. E.; Okabayashi, M. [Princeton Plasma Physics Laboratory, Princeton University, PO Box 451, Princeton, New Jersey 08543-0451 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, PO Box 451, Princeton, New Jersey 08543-0451 (United States); Strait, E. J.; Turnbull, A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
2014-05-15T23:59:59.000Z
A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does not contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.
Boyer, Edmond
in the patient head. Yet, the skull anisotropy happens to be highly anisotropic, and must then be modeled.e. for the brain and the scalp). A domain decomposition (DD) framework allows to split the global system. This work presents such a coupling formulation of a 3-DD method solving iteratively a BEM for the brain
Discrete Element Modeling Results of Proppant Rearrangement in the Cooke Conductivity Cell
Earl Mattson; Hai Huang; Michael Conway; Lisa O'Connell
2014-02-01T23:59:59.000Z
The study of propped fracture conductivity began in earnest with the development of the Cooke cell which later became part of the initial API standard. Subsequent developments included a patented multicell design to conduct 4 tests in a press at the same time. Other modifications have been used by various investigators. Recent studies by the Stim-Lab proppant consortium have indicated that the flow field across a Cooke proppant conductivity testing cell may not be uniform as initially believed which resulted is significantly different conductivity results. Post test analysis of low temperature metal alloy injections at the termination of proppant testing prior to the release of the applied stress suggest that higher flow is to be expected along the sides and top of the proppant pack than compared to the middle of the pack. To evaluate these experimental findings, a physics-based two-dimensional (2-D) discrete element model (DEM) was developed and applied to simulate proppant rearrangement during stress loading in the Cooke conductivity cell and the resulting porosity field. Analysis of these simulations are critical to understanding the impact of modification to the testing cell as well as understanding key proppant conductivity issues such as how these effects are manifested in proppant concentration testing results. The 2-D DEM model was constructed to represent a realistic cross section of the Cooke cell with a distribution of four material properties, three that represented the Cooke cell (steel, sandstone,square rings), and one representing the proppant. In principle, Cooke cell materials can be approximated as assemblies of independent discrete elements (particles) of various sizes and material properties that interact via cohesive interactions, repulsive forces, and frictional forces. The macroscopic behavior can then be modeled as the collective behavior of many interacting discrete elements. This DEM model is particularly suitable for modeling proppant mechanical interactions subjected to an applied stress, where the experimental cell is represented as a cohesive body composed of a large number of discrete elements, and proppants can be modeled as the individual discrete particles with various sizes (following the proppant size distribution-density function used in the test) that exhibit no cohesive strength between the particles. Initial 2-D DEM modeling results suggest that proppant rearrangement and non-uniform stress distribution across the proppant pack results in significant non-uniform porosity distribution across the Cooke cell. Larger porosities develop along the edge of the proppant pack beneath the square ring seal and would result in a disproportionate higher flow field along these edges as compared to the middle of the proppant pack. These results suggest that reported conductivity values determined by the Cooke cell may be biased to overestimate the actual conductivity of the proppant at high stresses and that modifications to the standard Cooke cell will affect the magnitude of this bias.
TXLINE-2: a finite length model to simulate the dispersion of pollutants from roadways
Schroeder, James Henry
2012-06-07T23:59:59.000Z
Modelling Near Roadways Gradient Transport Approach B. Existing Dispersion Models HIWAY-2 CALINE-3 TXLINE C. Methods of Deteimining Source Strl ngth 12 O. Methods of Testing and Compar1ng Models ties s Balance Tea t Comparison to Data l4 E. Data... Dispersion From Roadways E. Link Capabilities F. Comparison of Dispets1 on Mocieis Using Existing Data 72 Comparison to the GM Data 72 Comparison to the Texas Data 75 Comparison to the SRI Data General Discussion 90 CHAPTER V TABLE OF CONTENTS...
Arslan, Melis
2005-01-01T23:59:59.000Z
Many biological, natural and synthetic materials possess a networked or micro-truss-like microstructure. In this thesis work, a general microstructurally-informed continuum level constitutive model of the large stretch ...
Smart finite state devices: A modeling framework for demand response technologies
Turitsyn, Konstantin
We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the ...
Use of element model to evaluate transmissibility reduction due to barriers
Svanes, T.; South, D.; Dronen, O.M. [Statoil, Bergen (Norway)
1997-08-01T23:59:59.000Z
Water breakthrough has been observed a year earlier than expected in the productive Oseberg Formation in the Veslefrikk Field. Production data revealed extensive water override, whereas the opposite situation was expected based on a homogeneous and coarse flow simulation model. A new model was developed to include geological heterogeneities using a simple upscaling method. The Oseberg Fm. consists of an upper homogeneous unit (zone 2) and a lower unit containing thin barriers of shale and calcite cemented sandstone (zone 1). The barrier content varies laterally. When barriers are distributed in a complex 3D pattern, they reduce the upscaled horizontal transmissibility more than what is obtained by multiplying the sand permeability by the net-to-gross ratio (N/G). However, the transmissibility reduction strongly depends on the spatial distribution of barriers and their geometry. Therefore, a fine scale element model was used to derive the average transmissibility reduction as a function of N/G for alternative geological descriptions of the barriers. A geo-statistical method called General Marked Point Process was used to generate the fine scale descriptions. This work has resulted in a simple upscaling routine for horizontal transmissibility, which represents an effective bridge between geological evaluation of uncertainties and fluid flow simulation. The method combines geo-statistical and deterministic modelling in an elegant manner, recognising that most often these methods complement one another.
Quantum Mechanics associated with a Finite Group
Robert W. Johnson
2006-04-20T23:59:59.000Z
I describe, in the simplified context of finite groups and their representations, a mathematical model for a physical system that contains both its quantum and classical aspects. The physically observable system is associated with the space containing elements fxf for f an element in the regular representation of a given finite group G. The Hermitian portion of fxf is the Wigner distribution of f whose convolution with a test function leads to a mathematical description of the quantum measurement process. Starting with the Jacobi group that is formed from the semidirect product of the Heisenberg group with its automorphism group SL(2,F{N}) for N an odd prime number I show that the classical phase space is the first order term in a series of subspaces of the Hermitian portion of fxf that are stable under SL(2,F{N}). I define a derivative that is analogous to a pseudodifferential operator to enable a treatment that parallels the continuum case. I give a new derivation of the Schrodinger-Weil representation of the Jacobi group. Keywords: quantum mechanics, finite group, metaplectic. PACS: 03.65.Fd; 02.10.De; 03.65.Ta.
Optimization of relativistic mean field model for finite nuclei to neutron star matter
B. K. Agrawal; A. Sulaksono; P. -G. Reinhard
2012-04-12T23:59:59.000Z
We have optimized the parameters of extended relativistic mean-field model using a selected set of global observables which includes binding energies and charge radii for nuclei along several isotopic and isotonic chains and the iso-scalar giant monopole resonance energies for the $^{90}$Zr and $^{208}$Pb nuclei. The model parameters are further constrained by the available informations on the energy per neutron for the dilute neutron matter and bounds on the equations of state of the symmetric and asymmetric nuclear matter at supra-nuclear densities. Two new parameter sets BSP and IUFSU* are obtained, later one being the variant of recently proposed IUFSU parameter set. The BSP parametrization uses the contributions from the quartic order cross-coupling between $\\omega$ and $\\sigma$ mesons to model the high density behaviour of the equation of state instead of the $\\omega$ meson self-coupling as in the case of IUFSU* or IUFSU. Our parameter sets yield appreciable improvements in the binding energy systematics and the equation of state for the dilute neutron matter. The importance of the quartic order $\\omega-\\sigma$ cross coupling term of the extended RMF model, as often ignored, is realized.
Surety of human elements of high consequence systems: An organic model
FORSYTHE,JAMES C.; WENNER,CAREN A.
2000-04-25T23:59:59.000Z
Despite extensive safety analysis and application of safety measures, there is a frequent lament, ``Why do we continue to have accidents?'' Two breakdowns are prevalent in risk management and prevention. First, accidents result from human actions that engineers, analysts and management never envisioned and second, controls, intended to preclude/mitigate accident sequences, prove inadequate. This paper addresses the first breakdown, the inability to anticipate scenarios involving human action/inaction. The failure of controls has been addressed in a previous publication (Forsythe and Grose, 1998). Specifically, this paper presents an approach referred to as surety. The objective of this approach is to provide high levels of assurance in situations where potential system failure paths cannot be fully characterized. With regard to human elements of complex systems, traditional approaches to human reliability are not sufficient to attain surety. Consequently, an Organic Model has been developed to account for the organic properties exhibited by engineered systems that result from human involvement in those systems.
Zack, Thomas
Combined thermodynamic and rare earth element modelling of garnet growth during subduction and preserve complex growth zonation patterns with respect to both major and rare earth elements (REE). Due at ultrahigh-pressure conditions. Mass-balance of the rare earth element distribution among the modelled stable
Smart Finite State Devices: A Modeling Framework for Demand Response Technologies
Turitsyn, Konstantin; Ananyev, Maxim; Chertkov, Michael
2011-01-01T23:59:59.000Z
We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the following four types: (a) optional loads that can be shed, e.g. light dimming; (b) deferrable loads that can be delayed, e.g. dishwashers; (c) controllable loads with inertia, e.g. thermostatically-controlled loads, whose task is to maintain an auxiliary characteristic (temperature) within pre-defined margins; and (d) storage devices that can alternate between charging and generating. Our analysis of the devices seeks to find their optimal price-taking control strategy under a given stochastic model of the distribution market.
Pion condensation in the two--flavor chiral quark model at finite baryochemical potential
T. Herpay; P. Kovcs
2008-11-17T23:59:59.000Z
Pion condensation is studied at one--loop level and nonzero baryochemical potential in the framework of two flavor constituent quark model using the one--loop level optimized perturbation theory for the resummation of the perturbative series. A Landau type of analysis is presented for the investigation of the phase boundary between the pion condensed/non-condensed phases. The statement that the condensation starts at $\\muI = m_{\\pi}$ is slightly modified by one--loop corrections. The second order critical surface is determined and analysed in the $\\muI-\\muB-T$ space. The $\\muI$ dependence of the one--loop level charged pion pole masses is also studied.
Boundary Conditions of the Hydro-Cascade Model and Relativistic Kinetic Equations for Finite Domains
K. A. Bugaev
2004-01-29T23:59:59.000Z
A detailed analysis of the coupled relativistic kinetic equations for two domains separated by a hypersurface having both space- and time-like parts is presented. Integrating the derived set of transport equations, we obtain the correct system of the hydro+cascade equations to model the relativistic nuclear collision process. Remarkably, the conservation laws on the boundary between domains conserve separately both the incoming and outgoing components of energy, momentum and baryonic charge. Thus, the relativistic kinetic theory generates twice the number of conservation laws compared to traditional hydrodynamics. Our analysis shows that these boundary conditions between domains, the three flux discontinuity, can be satisfied only by a special superposition of two cut-off distribution functions for the ``out'' domain. All these results are applied to the case of the phase transition between quark gluon plasma and hadronic matter. The possible consequences for an improved hydro+cascade description of the relativistic nuclear collisions are discussed. The unique properties of the three flux discontinuity and their effect on the space-time evolution of the transverse expansion are also analyzed. The possible modifications of both transversal radii from pion correlations generated by a correct hydro+cascade approach are discussed.
Lo, F. S.; Lee, T. H. [Department of Mechanical Engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China)] [Department of Mechanical Engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China); Lu, P. S. [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China)] [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China); Ragan-Kelley, B. [Applied Science and Technology, University of California, Berkeley, California 94720 (United States) [Applied Science and Technology, University of California, Berkeley, California 94720 (United States); Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Minnich, A. [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States) [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125 (United States); Lin, M. C., E-mail: mingchiehlin@gmail.com [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China); Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Verboncoeur, J. P. [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States) [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Department of Electrical and Computing Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)
2014-02-15T23:59:59.000Z
A thermionic energy converter (TEC) is a static device that converts heat directly into electricity by boiling electrons off a hot emitter surface across a small inter-electrode gap to a cooler collector surface. The main challenge in TECs is overcoming the space charge limit, which limits the current transmitted across a gap of a given voltage and width. We have verified the feasibility of studying and developing a TEC using a bounded finite-difference time-domain particle-in-cell plasma simulation code, OOPD1, developed by Plasma Theory and Simulation Group, formerly at UC Berkeley and now at Michigan State University. In this preliminary work, a TEC has been modeled kinetically using OOPD1, and the accuracy has been verified by comparing with an analytically solvable case, giving good agreement. With further improvement of the code, one will be able to quickly and cheaply analyze space charge effects, and seek designs that mitigate the space charge effect, allowing TECs to become more efficient and cost-effective.
Elements & Compounds Atoms (Elements)
Frey, Terry
#12;Elements & Compounds #12;Atoms (Elements) Molecules (Compounds) Cells Elements & Compounds #12 #12;First shell Second shell Third shell Hydrogen 1H Lithium 3Li Sodium 11Na Beryllium 4Be Magnesium energy Higher energy (a) A ball bouncing down a flight of stairs provides an analogy for energy levels
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE ...
2014-05-20T23:59:59.000Z
adaptive strategy is established for the diffraction grating problem, such that ...... applications in optical filters and guided mode resonance devices. the...
Finite element analysis of shells with layers
Hiller, Jean-Franois, 1974-
2002-01-01T23:59:59.000Z
It is well established that thin shell structures frequently feature narrow bands of strain concentration and localized displacement irregularities referred to as boundary and internal layers. It is crucial to capture these ...
Generalized finite element method for multiscale analysis
Zhang, Lin
2004-11-15T23:59:59.000Z
by the Partition of Unity Method (PUM). It is shown that the p-version of the Generalized FEM using mesh-based handbook functions is capable of achieving very high accuracy. It is also analyzed that the effect of the main factors affecting the accuracy...
Programing the Finite Element Method with Matlab
2002-10-03T23:59:59.000Z
Oct 3, 2002 ... font d denotes a vector or matrix which is of dimension of the ... following Matlab code which sets the row and column of a matrix A to zero.
Finite element approximation of coupled seismic and ...
GH are ice-like structures within the pore space that cause strong changes in ..... solved employing absorbing boundary conditions at the artificial boundaries.
PARTIALLY PENALIZED IMMERSED FINITE ELEMENT METHODS ...
2014-03-14T23:59:59.000Z
v+(x, y) = c+. 1 + c+. 2 x + c+. 3 y, if (x, y) ? K+, which satisfies the following jump conditions [38]: v?(D) = v+(D), v?(E) = v+(E), ??. ?v?. ?nDE. = ?+ ?v+. ?nDE.
Finite element simulation of electrorheological fluids
Rhyou, Chanryeol, 1973-
2005-01-01T23:59:59.000Z
Electrorheological (ER) fluids change their flow properties dramatically when an electric field is applied. These fluids are usually composed of dispersions of polarizable particles in an insulating base fluid or composed ...
Finite Element Approximation of Coupled Seismic and ...
2009-02-15T23:59:59.000Z
numerical approximation of coupled seismic and electromagnetic waves in 2D bounded fluid- saturated porous media, with absorbing boundary conditions at...
A NONCONFORMING MIXED FINITE ELEMENT METHOD FOR ...
1910-10-30T23:59:59.000Z
tric conductivity from measurements of natural electric and magnetic fields on the ... have been widely used in electrical engineering applications, with the best-...
DOMAIN DECOMPOSITION FOR A MIXED FINITE ELEMENT ...
SIAM (#1) 1035 2001 Apr 10 12:32:38
2003-03-12T23:59:59.000Z
... porous media, where highly discontinuous conductivity coefficients are also ...... [14] B. Smith, P. Bjrstad, and W. Gropp, Domain Decomposition, Cambridge
Construction of Higher Order Finite Element with
Kern, Michel
: intersection of null spaces of rules. Linear inequality in integers, gives as many un knowns as equations as generating polynomial ideal Solutions depend only on ideal, not particular generator set. Gr#bner basis: generator for polynomial ideal (Buchberger). 7 #12; ' & $ % Fgb algorithm Buchberger's algorithm
An AMR Capable Finite Element Diffusion Solver
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout theOFFICEAmes Laboratory Site Sustainabilityupgraded x-rayopticalAMR
Control-volume mixed finite element methods
1998-01-23T23:59:59.000Z
Z. Cai a, J.E. Jones b, S.F. McCormick c and T.F. Russell d a Center for ...... (59). The Darcy equations for vertical faces normal to x-fluxes and y-fluxes would be.
Romero Gomez, Pedro DJ; Richmond, Marshall C.
2014-04-17T23:59:59.000Z
Evaluating the consequences from blade-strike of fish on marine hydrokinetic (MHK) turbine blades is essential for incorporating environmental objectives into the integral optimization of machine performance. For instance, experience with conventional hydroelectric turbines has shown that innovative shaping of the blade and other machine components can lead to improved designs that generate more power without increased impacts to fish and other aquatic life. In this work, we used unsteady computational fluid dynamics (CFD) simulations of turbine flow and discrete element modeling (DEM) of particle motion to estimate the frequency and severity of collisions between a horizontal axis MHK tidal energy device and drifting aquatic organisms or debris. Two metrics are determined with the method: the strike frequency and survival rate estimate. To illustrate the procedure step-by-step, an exemplary case of a simple runner model was run and compared against a probabilistic model widely used for strike frequency evaluation. The results for the exemplary case showed a strong correlation between the two approaches. In the application case of the MHK turbine flow, turbulent flow was modeled using detached eddy simulation (DES) in conjunction with a full moving rotor at full scale. The CFD simulated power and thrust were satisfactorily comparable to experimental results conducted in a water tunnel on a reduced scaled (1:8.7) version of the turbine design. A cloud of DEM particles was injected into the domain to simulate fish or debris that were entrained into the turbine flow. The strike frequency was the ratio of the count of colliding particles to the crossing sample size. The fish length and approaching velocity were test conditions in the simulations of the MHK turbine. Comparisons showed that DEM-based frequencies tend to be greater than previous results from Lagrangian particles and probabilistic models, mostly because the DEM scheme accounts for both the geometric aspects of the passage event ---which the probabilistic method does--- as well as the fluid-particle interactions ---which the Lagrangian particle method does. The DEM-based survival rates were comparable to laboratory results for small fish but not for mid-size fish because of the considerably different turbine diameters. The modeling framework can be used for applications that aim at evaluating the biological performance of MHK turbine units during the design phase and to provide information to regulatory agencies needed for the environmental permitting process.
Schunk, P.R.; Sackinger, P.A.; Rao, R.R. [and others] [and others
1996-01-01T23:59:59.000Z
GOMA is a two- and three-dimensional finite element program which excels in analyses of manufacturing processes, particularly those involving free or moving interfaces. Specifically, the full-Newton-coupled heat, mass, momentum, and pseudo-solid mesh motion algorithm makes GOMA ideally suited for simulating processes in which the bulk fluid transport is closely coupled to the interfacial physics. Examples include, but are not limited to, coating and polymer processing flows, soldering, crystal growth, and solid-network or solution film drying. The code is based on the premise that any boundary can be (1) moving or free, with an apriori unknown position dictated by the distinguishing physics, (2) fixed, according to a global analytical representation, or (3) moving in time and space under user-prescribed kinematics. The goal is to enable the user to predict boundary position or motion simultaneously with the physics of the problem being analyzed and to pursue geometrical design studies and fluid-structure interaction problems. The moving mesh algorithm treats the entire domain as a computational Lagrangian solid that deforms subject to the physical principles which dictate boundary position. As an added benefit, the same Lagrangian solid mechanics can be exploited to solve multi-field problems for which the solid motion and stresses interact with other transport phenomena, either within the same material phase (e.g. shrinking coating) or in neighboring material phases (e.g. flexible blade coating). Thus, analyses of many fluid-structure interaction problems and deformable porous media problems are accessible. This document serves as a user`s guide and reference for GOMA and provides a brief overview of GOMA`s capabilities, theoretical background, and classes of problems for which it is targeted.
Whittet, D. C. B. [New York Center for Astrobiology, and Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States)
2010-02-20T23:59:59.000Z
This paper assesses the implications of a recent discovery that atomic oxygen is being depleted from diffuse interstellar gas at a rate that cannot be accounted for by its presence in silicate and metallic oxide particles. To place this discovery in context, the uptake of elemental O into dust is considered over a wide range of environments, from the tenuous intercloud gas and diffuse clouds sampled by the depletion observations to dense clouds where ice mantles and gaseous CO become important reservoirs of O. The distribution of O in these contrasting regions is quantified in terms of a common parameter, the mean number density of hydrogen (n{sub H}). At the interface between diffuse and dense phases (just before the onset of ice-mantle growth) as much as {approx}160 ppm of the O abundance is unaccounted for. If this reservoir of depleted oxygen persists to higher densities it has implications for the oxygen budget in molecular clouds, where a shortfall of the same order is observed. Of various potential carriers, the most plausible appears to be a form of O-bearing carbonaceous matter similar to the organics found in cometary particles returned by the Stardust mission. The 'organic refractory' model for interstellar dust is re-examined in the light of these findings, and it is concluded that further observations and laboratory work are needed to determine whether this class of material is present in quantities sufficient to account for a significant fraction of the unidentified depleted oxygen.
Civitarese, Osvaldo [Department of Physics, University of La Plata, c.c. 67 1900, La Plata Argentina (Argentina); Suhonen, Jouni [Department of Physics, University of Jyvskyl, PO Box 35, FIN-40014 (Finland)
2013-12-30T23:59:59.000Z
In this work we report on general properties of the nuclear matrix elements involved in the neutrinoless double ?{sup ?} decays (0??{sup ?}?{sup ?} decays) of several nuclei. A summary of the values of the NMEs calculated along the years by the Jyvskyl-La Plata collaboration is presented. These NMEs, calculated in the framework of the quasiparticle random phase approximation (QRPA), are compared with those of the other available calculations, like the Shell Model (ISM) and the interacting boson model (IBA-2)
Introduction Positive finite rank . . .
Li, Chi-Kwong
Introduction Positive finite rank . . . Positive finite rank . . . Positive finite rank . . . ¯? I qixf1981@sxu.edu.cn #12;Introduction Positive finite rank . . . Positive finite rank . . . Positive finite rank . . . ¯? I K 12 19 £ ¶w« ' 4 ò ? 1 Introduction · In quantum mechanics, a quantum system
Modeling of the Thermal Field in Dissimilar Alloy Ultrasonic Welding
Jedrasiak, P.; Shercliff, H. R.; Chen, Y. C.; Wang, L.; Prangnell, P.; Robson, J.
2014-12-10T23:59:59.000Z
This paper describes a finite element model for predicting the temperature field in high power ultrasonic welding aluminum AA6111 to two dissimilar alloys, magnesium AZ31, and low carbon steel DC04. Experimental thermocouple and other evidence...
Irbäck, Anders
at finite temperature Anders Irba¨cka) and Frank Potthastb) Department of Theoretical Physics, University. We find that by these algorithms one gains large factors in efficiency in comparison to a fairly well-defined shape. This phase is interesting from the viewpoint of proteins, but for a generic
Rath, P. K. [Department of Physics, University of Lucknow, Lucknow 226007 (India); Chandra, R. [Department of Physics, University of Lucknow, Lucknow 226007 (India); Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India); Chaturvedi, K. [Department of Physics, Bundelkhand University, Jhansi 284128 (India); Raina, P. K. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India); Hirsch, J. G. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 Mexico, D.F. (Mexico)
2010-12-15T23:59:59.000Z
The nuclear transition matrix elements M{sup (0{nu})} for the neutrinoless {beta}{beta} decay of {sup 94,96}Zr, {sup 98,100}Mo, {sup 104}Ru, {sup 110}Pd, {sup 128,130}Te, and {sup 150}Nd isotopes in the case of 0{sup +}{yields}0{sup +} transition are calculated using the projected-Hartree-Fock-Bogoliubov wave functions, which are eigenvectors of four different parametrizations of a Hamiltonian with pairing plus multipolar effective two-body interaction. Employing two (three) different parametrizations of Jastrow-type short-range correlations, a set of eight (twelve) different nuclear transition matrix elements M{sup (0{nu})} is built for each decay, whose averages in conjunction with their standard deviations provide an estimate of the model's uncertainties.
Key Elements of and Materials Performance Targets for Highly Insulating Window Frames
Gustavsen, Arild
2012-01-01T23:59:59.000Z
finite-element method (FEM) program, THERM (Finlayson et al. , 1998), to solve the conductive heat-transfer
Hydrogeologic Modeling: GLY-5826 Meeting time: T, Th 11-12:15
Sukop, Mike
11. Finite Element Methods a. MicroFEM b. SUTRA 12. Fractured Media 13. Analytic Element models Level: Graduate 5826 Sections: 1 Course Catalogue Description Techniques used in modeling groundwater introductions to the theory and implementation of hydrogeological modeling techniques. Students will develop
Porohyperelastic anatomical models for hydrocephalus and idiopathic intracranial hypertension
Kim, Hakseung; Min, Byoung-Kyong; Park, Dae-Hyeon; Hawi, Stanley; Kim, Byung-Jo; Czosnyka, Zofia; Czosnyka, Marek; Sutcliffe, Michael P. F.; Kim, Dong-Joo
2015-02-06T23:59:59.000Z
:435-438, 2007 50. Ruan JS, Khalil T, King AI: Human head dynamic response to side impact by finite element modeling. J Biomech Eng 113:276-283, 1991 51. Sarkar S, Majumder S, Roychowdhury A: Response of human head under static and dynamic load using finite...
Material model library for explicit numerical codes
Hofmann, R.; Dial, B.W.
1982-08-01T23:59:59.000Z
A material model logic structure has been developed which is useful for most explicit finite-difference and explicit finite-element Lagrange computer codes. This structure has been implemented and tested in the STEALTH codes to provide an example for researchers who wish to implement it in generically similar codes. In parallel with these models, material parameter libraries have been created for the implemented models for materials which are often needed in DoD applications.
Painting-to-3D Model Alignment Via Discriminative Visual Elements
Paris-Sud XI, Université de
] as well as simplified models obtained from 3D mod- eling tools such as Google Sketchup. Example results
Gillespie, G.H., Brown, T.A.
1998-05-01T23:59:59.000Z
A set of optical models for a variety of electrostatic lenses and accelerator columns has been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code including space charge that is often used to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators when the effects of beam current may be important. Several new matrix models have been developed that allow the code to be used for modeling beam lines and accelerators with electrostatic components. The new models include a number of options for: (1) einzel lenses, (2) accelerator columns, (3) electrostatic deflectors (prisms), and (4) an electrostatic quadrupole. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The new models for (2) are described in this paper, selected comparisons with other calculations are presented, and a beamline application is summarized.
Numerical Modeling of the Transient Thermal Interference of Vertical U-Tube Haet Exchangers
Muraya, Norman K.
Non-linear finite element models were developed to simulate transient heat and mass transfer in the soil surrounding the ground heat exchangers of ground-coupled heat pumps (GCHPs) operating in the cooling mode. Parametric studies were performed...
A Continuum Coupled Moisture-mechanical Constitutive Model for Asphalt Concrete
Shakiba, Maryam
2013-12-09T23:59:59.000Z
constitutive relationships are implemented in the Pavement Analysis using Nonlinear Damage Approach (PANDA) finite element (FE) package to model the moisture damage effect on the complex environmental-mechanical response of asphalt concrete. The developed...
Huang, Chien-Wei
2009-05-15T23:59:59.000Z
pavements is illustrated using finite element simulations. The constitutive model developed in this study can describe the behavior of asphalt materials (asphalt binder, asphalt mastic and mixtures) under various testing conditions. This study also achieved...
Peters, Andrew
2011-08-04T23:59:59.000Z
arterial hypertension (PAH), to identify the hemodynamic attributes which could be altered to ameliorate the progression of these diseases. We then simulated blood flow through five, simple finite element vessel models to determine the effects of stents...
Microstructure-Based Computational Modeling of TRIP Steels with Dispersed Particles
Diaz, Sara Cristina
2012-10-19T23:59:59.000Z
in this study. The ideas surrounding the behavior of transformation induced plasticity (TRIP) steels and particle reinforced composites are combined and investigated. A finite element model (FEM) is created to investigate the effects of dispersed ceramic...
Material characterization of high-voltage lithium-ion battery models for crashworthiness analysis
Meier, Joseph D. (Joseph David)
2013-01-01T23:59:59.000Z
A three-phased study of the material properties and post-impact behavior of prismatic pouch lithium-ion battery cells was conducted to refine computational finite element models and explore the mechanisms of thermal runaway ...
A 3-D mathematical model to identify organ-specific risks in rats during thermal stress
- vention and management. computational modeling; core temperature; finite element method; multiorgan obtained from medical imaging and incorporates the key mechanisms of heat transfer during thermoregulation outcomes associated with heat stress is critical for effective management and mitigation of injury, which
Neacsu, Andrei [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) 407 Atomistilor, Magurele-Bucharest 077125 (Romania)
2010-11-24T23:59:59.000Z
In this paper we present two Shell Model approaches for computing the two-body matrix elements involved in the neutrinoless double beta decay of {sup 48}Ca. One of the methods involves integration of the radial part over the momentum space, while the other only requires computations in the coordinate space. This has an influence in the complexity of the numerical approach and the necessary computation time. We will explain how this reflects into the obtained results, pointing out the advantages and the limitations of each method.
Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model
Paris-Sud XI, Université de
Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model-off dominated. We demonstrate the ability of our cohesive zone model in simulating the hydraulic fracture in all these propagation regimes. Keywords: Hydraulic fracture, Cohesive zone model, Finite element analysis, Hydro
Physics based lumped element circuit model for nanosecond pulsed dielectric barrier discharges
Roy, Subrata
of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611, USA 2 Vehicle, that value can be input to a computational fluid dynamics solver as an energy source term resulting in a coupled fluid/plasma dynamics model. Multiphysics models of this type are required in order to study
Huang, Hai; Plummer, Mitchell; Podgorney, Robert
2013-02-01T23:59:59.000Z
Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.
Hai Huang; Ben Spencer; Jason Hales
2014-10-01T23:59:59.000Z
A discrete element Model (DEM) representation of coupled solid mechanics/fracturing and heat conduction processes has been developed and applied to explicitly simulate the random initiations and subsequent propagations of interacting thermal cracks in a ceramic nuclear fuel pellet during initial rise to power and during power cycles. The DEM model clearly predicts realistic early-life crack patterns including both radial cracks and circumferential cracks. Simulation results clearly demonstrate the formation of radial cracks during the initial power rise, and formation of circumferential cracks as the power is ramped down. In these simulations, additional early-life power cycles do not lead to the formation of new thermal cracks. They do, however clearly indicate changes in the apertures of thermal cracks during later power cycles due to thermal expansion and shrinkage. The number of radial cracks increases with increasing power, which is consistent with the experimental observations.
Smith, Richard Edwin
1992-01-01T23:59:59.000Z
-dimensionalized numerical and analytical solutions of the one-dimensional model using identical parameters to solve Equation 3 when KH is homogeneous. . . . . . . . . . . , , , . . . . . . . . . . . , . . . . . . . . . . . , . , 36 12 Total pore pressure at the end... deposition) for the one-dimensional model. . 40 14 Total pore pressure at the end of Stage 3 (thrust loading) for the one- dimensional model. . 42 15 Decay of X with time beginning at the end of Stage 3 (thrust loading) for the one-dimensional model...
Summary compilation of shell element performance versus formulation.
Heinstein, Martin Wilhelm; Hales, Jason Dean (Idaho National Laboratory, Idaho Falls, ID); Breivik, Nicole L.; Key, Samuel W. (FMA Development, LLC, Great Falls, MT)
2011-07-01T23:59:59.000Z
This document compares the finite element shell formulations in the Sierra Solid Mechanics code. These are finite elements either currently in the Sierra simulation codes Presto and Adagio, or expected to be added to them in time. The list of elements are divided into traditional two-dimensional, plane stress shell finite elements, and three-dimensional solid finite elements that contain either modifications or additional terms designed to represent the bending stiffness expected to be found in shell formulations. These particular finite elements are formulated for finite deformation and inelastic material response, and, as such, are not based on some of the elegant formulations that can be found in an elastic, infinitesimal finite element setting. Each shell element is subjected to a series of 12 verification and validation test problems. The underlying purpose of the tests here is to identify the quality of both the spatially discrete finite element gradient operator and the spatially discrete finite element divergence operator. If the derivation of the finite element is proper, the discrete divergence operator is the transpose of the discrete gradient operator. An overall summary is provided from which one can rank, at least in an average sense, how well the individual formulations can be expected to perform in applications encountered year in and year out. A letter grade has been assigned albeit sometimes subjectively for each shell element and each test problem result. The number of A's, B's, C's, et cetera assigned have been totaled, and a grade point average (GPA) has been computed, based on a 4.0-system. These grades, combined with a comparison between the test problems and the application problem, can be used to guide an analyst to select the element with the best shell formulation.
Mod`ele Elements Finis d'un Pli Vocal Artificiel avec Couplage Hydro-elastique
Paris-Sud XI, Université de
Mod`ele El´ements Finis d'un Pli Vocal Artificiel avec Couplage Hydro-´elastique N. Hermanta , F formulation variationnelle du couplage hydro-élastique. Un premier calcul hyper-élastique simule le gonflement dans l'analyse modale des vibrations de petite amplitude du système hydro-élastique, permettant ainsi
Inverse Modeling for Coastal Seawater Intrusion
Politècnica de Catalunya, Universitat
, USA) #12;INTRODUCTION · Inverse modeling standard tool for groundwater modeling uncommonD3D.1 2D and 3D finite-element code for simulating variable-density groundwater problems · UCODE 3 and given time (i.e. at one observation location) on one of the parameters in the groundwater model
Verley, Jason C.; Axness, Carl L.; Hembree, Charles Edward; Keiter, Eric Richard; Kerr, Bert (New Mexico Institute of Mining and Technology, Socorro, NM)
2012-04-01T23:59:59.000Z
Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, many photocurrent compact models have suffered from accuracy issues due to the use of qualitative approximation, rather than mathematically correct solutions to the ambipolar diffusion equation. A practical consequence of this inaccuracy is that a given model calibration is trustworthy over only a narrow range of operating conditions. This report describes work to produce improved compact models for photocurrent. Specifically, an analytic model is developed for epitaxial diode structures that have a highly doped subcollector. The analytic model is compared with both numerical TCAD calculations, as well as the compact model described in reference [2]. The new analytic model compares well against TCAD over a wide range of operating conditions, and is shown to be superior to the compact model from reference [2].
Swaminathan, Madhavan
system become increasingly more critical regarding the signal integrity and electromagnetic interference electromagnetic interference. Hence, accurate modeling of power/ground planes is critical to estimate the noise
Modeling thermal/chemical/mechanical response of energetic materials
Baer, M.R.; Hobbs, M.L.; Gross, R.J. [and others
1995-07-01T23:59:59.000Z
An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.
John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy
2011-11-11T23:59:59.000Z
We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.
AN IMPLICIT 2-D DEPTH-AVERAGED FINITE-VOLUME MODEL OF FLOW AND SEDIMENT TRANSPORT IN COASTAL WATERS
US Army Corps of Engineers
diffusion induced by currents, waves and wave breaking. The model uses a quadtree rectangular mesh. However, because of the dynamic nature of currents and waves on the coast, neither bed load nor suspended with the spectral wave transformation model called CMS-Wave, which solves the steady-state wave-action balance
He, Jin-zhong, E-mail: viewsino@163.com; Yao, Shu-zhen [China University of Geosciences, State Key Laboratory of Geological Processes and Mineral Resources (China)] [China University of Geosciences, State Key Laboratory of Geological Processes and Mineral Resources (China); Zhang, Zhong-ping; You, Guan-jin [Geological Surveying Institute of Gansu Province (China)] [Geological Surveying Institute of Gansu Province (China)
2013-03-15T23:59:59.000Z
With the help of complexity indices, we quantitatively studied multifractals, frequency distributions, and linear and nonlinear characteristics of geochemical data for exploration of the Daijiazhuang Pb-Zn deposit. Furthermore, we derived productivity differentiation models of elements from thermodynamics and self-organized criticality of metallogenic systems. With respect to frequency distributions and multifractals, only Zn in rocks and most elements except Sb in secondary media, which had been derived mainly from weathering and alluviation, exhibit nonlinear distributions. The relations of productivity to concentrations of metallogenic elements and paragenic elements in rocks and those of elements strongly leached in secondary media can be seen as linear addition of exponential functions with a characteristic weak chaos. The relations of associated elements such as Mo, Sb, and Hg in rocks and other elements in secondary media can be expressed as an exponential function, and the relations of one-phase self-organized geological or metallogenic processes can be represented by a power function, each representing secondary chaos or strong chaos. For secondary media, exploration data of most elements should be processed using nonlinear mathematical methods or should be transformed to linear distributions before processing using linear mathematical methods.
Doran, J. C.; Fast, Jerome D.; Barnard, James C.; Laskin, Alexander; Desyaterik, Yury; Gilles, Marry K.; Hopkins, Rebecca J.
2008-03-07T23:59:59.000Z
We use a Lagrangian dispersion model driven by a mesoscale model with four-dimensional data assimilation to simulate the dispersion of elemental carbon (EC) over a region encompassing Mexico City and its surroundings, the study domain for the 2006 MAX-MEX experiment, which was a component of the MILAGRO campaign. The results are used to identify periods when biomass burning was likely to have had a significant impact on the concentrations of elemental carbon at two sites, T1 and T2, downwind of the city, and when emissions from the Mexico City Metropolitan Area (MCMA) were likely to have been more important. They are also used to estimate the median ages of EC affecting the specific absorption of light, aABS, at 870 nm as well as to identify periods when the urban plume from the MCMA was likely to have been advected over T1 and T2. Values of aABS at T1, the nearer of the two sites to Mexico City, were smaller at night and increased rapidly after mid-morning, peaking in the mid-afternoon. The behavior is attributed to the coating of aerosols with substances such as sulfate or organic carbon during daylight hours, but such coating appears to be limited or absent at night. Evidence for this is provided by scanning electron microscope images of aerosols collected at three sampling sites. During daylight hours the values of aABS did not increase with aerosol age for median ages in the range of 1-4 hours. There is some evidence for absorption increasing as aerosols were advected from T1 to T2 but the statistical significance of that result is not strong.
Frandsen, Michael W. (Helena, MT); Wessol, Daniel E. (Bozeman, MT); Wheeler, Floyd J. (Idaho Falls, ID)
2001-01-16T23:59:59.000Z
Methods and computer executable instructions are disclosed for ultimately developing a dosimetry plan for a treatment volume targeted for irradiation during cancer therapy. The dosimetry plan is available in "real-time" which especially enhances clinical use for in vivo applications. The real-time is achieved because of the novel geometric model constructed for the planned treatment volume which, in turn, allows for rapid calculations to be performed for simulated movements of particles along particle tracks there through. The particles are exemplary representations of neutrons emanating from a neutron source during BNCT. In a preferred embodiment, a medical image having a plurality of pixels of information representative of a treatment volume is obtained. The pixels are: (i) converted into a plurality of substantially uniform volume elements having substantially the same shape and volume of the pixels; and (ii) arranged into a geometric model of the treatment volume. An anatomical material associated with each uniform volume element is defined and stored. Thereafter, a movement of a particle along a particle track is defined through the geometric model along a primary direction of movement that begins in a starting element of the uniform volume elements and traverses to a next element of the uniform volume elements. The particle movement along the particle track is effectuated in integer based increments along the primary direction of movement until a position of intersection occurs that represents a condition where the anatomical material of the next element is substantially different from the anatomical material of the starting element. This position of intersection is then useful for indicating whether a neutron has been captured, scattered or exited from the geometric model. From this intersection, a distribution of radiation doses can be computed for use in the cancer therapy. The foregoing represents an advance in computational times by multiple factors of time magnitudes.
Bobby S Acharya; Michael R Douglas
2006-06-21T23:59:59.000Z
We present evidence that the number of string/$M$ theory vacua consistent with experiments is a finite number. We do this both by explicit analysis of infinite sequences of vacua and by applying various mathematical finiteness theorems.
Foulk, James Wesley
1997-01-01T23:59:59.000Z
A method for predicting the life of an embrittled metal matrix composite using the finite element method coupled with models for material inelasticity, surface embrittlement, and crack propagation was developed herein. The titanium metal matrix...
Stalnaker, Jack Lee
2005-11-01T23:59:59.000Z
plate-like targets, oriented in various geometries (parallel, perpendicular, and horizontal), mutual coupling ranges as high as twenty times the total magnetic ?eld. The e?ect of varying host conductivity is signi?cant, especially...
Raut, Ameeta A.
2010-07-14T23:59:59.000Z
} Residual Vector {T} Tangent Matrix ij? Cartesian Component of Stress Tensor ij? Cartesian Component of Strain Tensor e EW Work Done by External Forces e IW Work Done by Internal Forces xxS Shear Stiffness (GAKs) G Shear... ..... 6 2.3 Summary............................................................................................ 8 3. THEORETICAL FORMULATION OF EBT AND TBT ............................ 9 3.1 Background...
Mailhes, Corinne
Introduction During the launch of a satellite, the level of excitation is very high. However, the security frequencies. Finally we propose a global strategy and discuss the results we obtained on satellite JASON2. 1 to be correct when the Modal Assurance Criterion (MAC) is accurate enough. Centre National d'Etudes Spatiales
TRISO-Fuel Element Performance Modeling for the Hybrid LIFE Engine with Pu Fuel Blanket
DeMange, P; Marian, J; Caro, M; Caro, A
2010-02-18T23:59:59.000Z
A TRISO-coated fuel thermo-mechanical performance study is performed for the hybrid LIFE engine to test the viability of TRISO particles to achieve ultra-high burnup of a weapons-grade Pu blanket. Our methodology includes full elastic anisotropy, time and temperature varying material properties for all TRISO layers, and a procedure to remap the elastic solutions in order to achieve fast fluences up to 30 x 10{sup 25} n {center_dot} m{sup -2} (E > 0.18 MeV). In order to model fast fluences in the range of {approx} 7 {approx} 30 x 10{sup 25} n {center_dot} m{sup -2}, for which no data exist, careful scalings and extrapolations of the known TRISO material properties are carried out under a number of potential scenarios. A number of findings can be extracted from our study. First, failure of the internal pyrolytic carbon (PyC) layer occurs within the first two months of operation. Then, the particles behave as BISO-coated particles, with the internal pressure being withstood directly by the SiC layer. Later, after 1.6 years, the remaining PyC crumbles due to void swelling and the fuel particle becomes a single-SiC-layer particle. Unrestrained by the PyC layers, and at the temperatures and fluences in the LIFE engine, the SiC layer maintains reasonably-low tensile stresses until the end-of-life. Second, the PyC creep constant, K, has a striking influence on the fuel performance of TRISO-coated particles, whose stresses scale almost inversely proportional to K. Obtaining more reliable measurements, especially at higher fluences, is an imperative for the fidelity of our models. Finally, varying the geometry of the TRISO-coated fuel particles results in little differences in the scope of fuel performance. The mechanical integrity of 2-cm graphite pebbles that act as fuel matrix has also been studied and it is concluded that they can reliable serve the entire LIFE burnup cycle without failure.
Tabares-Velasco, P. C.; Christensen, C.; Bianchi, M.; Booten, C.
2012-07-01T23:59:59.000Z
Phase change materials (PCMs) represent a potential technology to reduce peak loads and HVAC energy consumption in buildings. There are few building energy simulation programs that have the capability to simulate PCM but their accuracy has not been completely tested. This report summarizes NREL efforts to develop diagnostic tests cases to obtain accurate energy simulations when PCMs are modeled in residential buildings.
Extremality of translation-invariant phases for a finite-state SOS-model on the binary tree
C. Kuelske; U. A. Rozikov
2014-11-21T23:59:59.000Z
We consider the SOS (solid-on-solid) model, with spin values $0,1,2$, on the Cayley tree of order two (binary tree). We treat both ferromagnetic and antiferromagnetic coupling, with interactions which are proportional to the absolute value of the spin differences. We present a classification of all translation-invariant phases (splitting Gibbs measures) of the model: We show uniqueness in the case of antiferromagnetic interactions, and existence of up to seven phases in the case of ferromagnetic interactions, where the number of phases depends on the interaction strength. Next we investigate whether these states are extremal or non-extremal in the set of all Gibbs measures, when the coupling strength is varied, whenever they exist. We show that two states are always extremal, two states are always non-extremal, while three of the seven states make transitions between extremality and non-extremality. We provide explicit bounds on those transition values, making use of algebraic properties of the models, and an adaptation of the method of Martinelli, Sinclair, Weitz.
Challenges in Continuum Modelling of Intergranular Fracture
Sethna, James P.
Challenges in Continuum Modelling of Intergranular Fracture V. R. Coffman*, J. P. Sethna , A. R-2501, USA Cornell Fracture Group, Rhodes Hall, Cornell University, Ithaca, NY 14853-2501, USA § Department fracture in polycrystals is often simulated by finite elements coupled to a cohesive zone model
Mustakerov, Ivan
) in order to satisfy the demand for all joinery elements. Along with this, it is necessary to find in the production planning of many industries such as the metallurgy, plastics, paper, glass, furniture, textile elements have to be manufactured using blanks of single standard size. This demands developing of methods
Efficient double beta decay nuclear matrix elements computations
Neacsu, Andrei [Horia Hulubei Foundation (FHH) 407 Atomistilor, Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH) 30 Reactorului, Magurele-Bucharest 077125 (Romania)
2012-11-20T23:59:59.000Z
We have developed a shell model code for the accurate computation of the two-body matrix elements of the transition operators involved in the neutrinoless double beta decay. This code features coupled cluster method short-range correlations with Jastrow-like functions, finite nucleon size effect and higher order nucleon current corrections. We present the results obtained for {sup 48}Ca and {sup 82}Se, then we compare them with other results in the literature. In the case of {sup 48}Ca, we also study the contributions of the included effects and find good agreement with other published results.
Low-Order Mathematical Modelling of Electric Double Layer Supercapacitors Using Spectral Methods
Drummond, Ross; Duncan, Stephen R
2014-01-01T23:59:59.000Z
This work investigates two physics-based models that simulate the non-linear partial differential algebraic equations describing an electric double layer supercapacitor. In one model the linear dependence between electrolyte concentration and conductivity is accounted for, while in the other model it is not. A spectral element method is used to discretise the model equations and it is found that the error convergence rate with respect to the number of elements is faster compared to a finite difference method. The increased accuracy of the spectral element approach means that, for a similar level of solution accuracy, the model simulation computing time is approximately 50% of that of the finite difference method. This suggests that the spectral element model could be used for control and state estimation purposes. For a typical supercapacitor charging profile, the numerical solutions from both models closely match experimental voltage and current data. However, when the electrolyte is dilute or where there is...
Integration of Different Wave Forcing Formulations with Nearshore Circulation Models
Sharma, Abhishek
2012-02-14T23:59:59.000Z
Wave-induced circulation in general coastal environments is simulated by coupling two widely-used finite-element models, namely, a refraction-diffraction-reflection model based on the elliptic mild-slope equation, and a two-dimensional (depth...
Romero, Vicente Jose
2011-11-01T23:59:59.000Z
This report explores some important considerations in devising a practical and consistent framework and methodology for utilizing experiments and experimental data to support modeling and prediction. A pragmatic and versatile 'Real Space' approach is outlined for confronting experimental and modeling bias and uncertainty to mitigate risk in modeling and prediction. The elements of experiment design and data analysis, data conditioning, model conditioning, model validation, hierarchical modeling, and extrapolative prediction under uncertainty are examined. An appreciation can be gained for the constraints and difficulties at play in devising a viable end-to-end methodology. Rationale is given for the various choices underlying the Real Space end-to-end approach. The approach adopts and refines some elements and constructs from the literature and adds pivotal new elements and constructs. Crucially, the approach reflects a pragmatism and versatility derived from working many industrial-scale problems involving complex physics and constitutive models, steady-state and time-varying nonlinear behavior and boundary conditions, and various types of uncertainty in experiments and models. The framework benefits from a broad exposure to integrated experimental and modeling activities in the areas of heat transfer, solid and structural mechanics, irradiated electronics, and combustion in fluids and solids.
A MODEL FOR ELEMENTAL CORONAL FLUX LOOPS C. BEVERIDGE1, D. W. LONGCOPE2 and E. R. PRIEST1
Priest, Eric
density in the low solar corona is far larger than any other form of energy. It follows that many coronal of an active region. Each unipolar area consists of a large number of elemental Solar Physics 216: 2740, 2003Mathematical Institute, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS, U.K. (e-mail: colinb
A MODEL FOR ELEMENTAL CORONAL FLUX LOOPS C. BEVERIDGE 1 , D. W. LONGCOPE 2 and E. R. PRIEST 1
Priest, Eric
density in the low solar corona is far larger than any other form of energy. It follows that many coronal of an active region. Each unipolar area consists of a large number of elemental Solar Physics 216: 27--40, 2003 Mathematical Institute, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS, U.K. (email: colinb
Babu, S.S.; Riemer, B.W.; Santella, M.L. [Oak Ridge National Lab., TN (United States); Feng, Z. [Edison Welding Inst., Columbus, OH (United States)
1998-11-01T23:59:59.000Z
An integrated model approach was proposed for relating resistance welding parameters to weldment properties. An existing microstructure model was used to determine the microstructural and property gradients in resistance spot welds of plain carbon steel. The effect of these gradients on the weld integrity was evaluated with finite element analysis. Further modifications to this integrated thermal-microstructure model are discussed.
Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding
Paris-Sud XI, Université de
- 1 - Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding Olivier dimensional finite element model has been developed to simulate weld bead formation in multi pass hybrid laser/gas metal arc welding. The model considers both a gas metal arc welding (GMAW) electrode and a laser beam
Thirumalai, Devarajan
Finite-temperature phase diagram of nonmagnetic impurities in high-temperature superconductors to the superconducting phase in cuprates which is eliminated for p 0.05; in the same region for these dilute impurity destruction of the superconducting phase.1,2 In yttrium barium copper oxide YBCO , the transition temperature
Choi, Myunghee [Retired] [Retired; Chan, Vincent S. [General Atomics] [General Atomics
2014-02-28T23:59:59.000Z
This final report describes the work performed under U.S. Department of Energy Cooperative Agreement DE-FC02-08ER54954 for the period April 1, 2011 through March 31, 2013. The goal of this project was to perform iterated finite-orbit Monte Carlo simulations with full-wall fields for modeling tokamak ICRF wave heating experiments. In year 1, the finite-orbit Monte-Carlo code ORBIT-RF and its iteration algorithms with the full-wave code AORSA were improved to enable systematical study of the factors responsible for the discrepancy in the simulated and the measured fast-ion FIDA signals in the DIII-D and NSTX ICRF fast-wave (FW) experiments. In year 2, ORBIT-RF was coupled to the TORIC full-wave code for a comparative study of ORBIT-RF/TORIC and ORBIT-RF/AORSA results in FW experiments.
Applying one-dimensional fluid thermal elements into a 3D CLIC accelerating strucutre
Raatikainen, Riku; sterberg, Kenneth; Riddone, Germana; Samoshkin, Alexander; Gudkov, Dmitry
2010-01-01T23:59:59.000Z
A finite element modeling method to simplify the analysis of coupled thermal-structural model for the CLIC accelerating structure is presented. In addition, the results of thermal and structural analyses for the accelerating structure are presented. Instead of using a standard 3D computational fluid dynamics (CFD) method for solving problems involving fluid dynamics and heat transfer in 3D environment, one-dimensional fluid thermal elements are used. In one-dimensional flow, the governing equations of fluid dynamics are considerably simplified. Thus, it is expected that the computational time for more complex simulations becomes shorter. The method was first applied to several test models, which demonstrated the suitability of the one-dimensional flow modeling. The results show that one-dimensional fluid flow reduces the computation time considerably allowing the modeling for the future larger assemblies with sufficient accuracy.
Finite N from Resurgent Large N
Couso-Santamara, Ricardo; Vaz, Ricardo
2015-01-01T23:59:59.000Z
Due to instanton effects, gauge-theoretic large N expansions yield asymptotic series, in powers of 1/N^2. The present work shows how to generically make such expansions meaningful via their completion into resurgent transseries, encoding both perturbative and nonperturbative data. Large N resurgent transseries compute gauge-theoretic finite N results nonperturbatively (no matter how small N is). Explicit calculations are carried out within the gauge theory prototypical example of the quartic matrix model. Due to integrability in the matrix model, it is possible to analytically compute (fixed integer) finite N results. At the same time, the large N resurgent transseries for the free energy of this model was recently constructed. Together, it is shown how the resummation of the large N resurgent transseries matches the analytical finite N results up to remarkable numerical accuracy. Due to lack of Borel summability, Stokes phenomena has to be carefully taken into account, implying that instantons play a dominan...
Iterative solutions to large sparse finite element equations
Wang, Hongbing
1995-01-01T23:59:59.000Z
direct solvers. The theory behind the convergence rate relationship and storage requirements for the preconditioned conjugate gradient methods using the diagonal scaling, incomplete Cholesky decomposition and SSOR preconditioners is explained in detail...
Mixed finite element methods for incompressible flow: Stationary ...
2010-04-14T23:59:59.000Z
May 14, 2009 ... 0, (conservation of mass) ... Contract grant sponsor: U.S. Department of Energy by University of California .... We use the standard notations and definitions for the Sobolev ...... minimum residual method applied to the system.
stabilized finite element methods for coupled geomechanics and ...
geomechanics and reservoir fluid flow simulations. There are, however ... coupled methods. The comparisons demonstrate consistent results on homogeneous ..... C Software Design. 153 ..... source of reservoir energy (Ruddy et al. 1989).
Finite element analysis of a coiled composite tubular
Judice, David Roy
2012-06-07T23:59:59.000Z
This study presents the design and stress analysis of a composite tubular that can be coiled onto large spools for ease of storage and installation on offshore platforms. The tube is analyzed under working pressure and tensile loads, as well...
Computational wind engineering using finite element package ADINA
Bajoria, Ankur
2008-01-01T23:59:59.000Z
Design of tall and long span structures is governed by the wind forces. Inadequate research in the field of wind dynamics has forced engineers to rely on design codes or wind tunnel tests for sufficient data. The present ...
Numerical Exercises Course Applied Finite Elements 2012 Tsunami Wave Amplification
Al Hanbali, Ahmad
waves seen on our car window as ripples on water sheets during heavy rain are also shallow water waves-Dimensional Linear Shallow Water Equations Linear shallow water equations (LSWE) describe the the motion of waves travelling on the free surface of a liquid, such as sea water. They govern the motion of small
ECI 212A: Finite Element Procedures in Applied Mechanics
Schladow, S. Geoffrey
Press, Boca Raton, FL, 2006. #12;Winter 2014 ECI 212A Instructor: N. Sukumar 2. T. J. R. Hughes (1987
Extended Finite Element Method for Fretting Fatigue Crack Propagation
Sukumar, N.
.D. Denia a , F.J. Fuenmayor a aDepartamento de Ingenier´ia Mec´anica y de Materiales Universidad Polit´ecnica de Valencia, Camino de Vera, 46022 Valencia, Spain. bDepartment of Civil and Environmental
An Abaqus implementation of the extended finite element method
Sukumar, N.
. Taranc´on a , F. J. Fuenmayor a aDepartamento de Ingenier´ia Mec´anica y de Materiales Universidad Polit´ecnica de Valencia, Camino de Vera, 46022 Valencia, Spain. bDepartment of Civil and Environmental
FLUX RECOVERY FROM PRIMAL HYBRID FINITE ELEMENT METHODS #
Chou, So-Hsiang
and Statistics, Bowling Green State University, Bowling Green, OH (chou@bgnet.bgsu.edu). The research
A finite element method using singular functions for the Poisson ...
2002-09-05T23:59:59.000Z
1Department of Mathematics; Purdue University; 1395 Mathematical Science ... Contract=grant sponsor: U.S. Department of Energy by Lawrence Livermore ...... Djaoua M. Equations Int?egrales pour un Probleme Singulier dans le Plan.
Least-squares finite elements and constrained evolution systems
Szypowski, Ryan
2008-01-01T23:59:59.000Z
D(CA) ? D( AC) ? X such that CAx = ACx for all x ? D. WithD is dense in D( C), and CAx = 0 = ACx for all x ? D. Thus,
Finite Element Methods for Nonlinear Acoustics in Fluids
resonating acoustic cavity, and a coupled elastic/acoustic system consisting of ... linear terms in these wave equations imply that the sound speed depends on the ... have zero shear modulus, this approach suffers from an infinite dimensional...
The Finite Volume Element Method for Diffusion ... - Purdue University
Dec 6, 2003 ... SIAM Journal on Numerical Analysis is currently published by ... was introduced several years earlier in the mechanical engineering literature While ... tCourant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New .... bid) = we vent-2%] / mews, .... Heat Transfer, 3 (1980), pp.
A piecewise linear finite element discretization of the diffusion equation
Bailey, Teresa S
2006-10-30T23:59:59.000Z
it discretizes the diffusion equation on an arbitrary polyhedral mesh. We implemented our method in the KULL software package being developed at Lawrence Livermore National Laboratory. This code previously utilized Palmer's method as its diffusion solver, which...
Discontinuous finite element methods for particle transport problems
Stone, Hiromi
2012-06-07T23:59:59.000Z
, and intcgratc over cell k: dxdy w, (x, y) lA. &iF (x, y, 0) F o (x, g) 8 (x, y, n)] V? = J x I/ ?(x, t/)r/(x, y). (5) We then apply Gauss's theorem to the leakage term and drop arguments of functions for simplicity: (6) where n is the outward unit normal... on the boundary of cell k. We refer Eq. (6) as the (k, i)*th weighted residual. We now insert DFEM approximation, Eq. (2), to the weighted residual equation (6): /?, ju, , ""' ? f dt w, n. H~'~'"' +P d? d'?9[ ? ~&$ f2 +u~, , +?, , o~l k k f dr, dy u...
Coupling of finite element and boundary integral methods for ...
"Peijun Li"
2009-11-09T23:59:59.000Z
Oct 8, 2009 ... sparse, and banded matrix; A12? is an Nn ? Ne rectangular and sparse ... ple MATLAB mesh generator distmesh2d by Persson and Strang [38] is ... 2 shows the graphs of the real part and the imaginary part of the field.
FINITE ELEMENT ANALYSIS OF STEEL WELDED COVERPLATE INCLUDING COMPOSITE DOUBLERS
Petri, Brad
2008-05-15T23:59:59.000Z
With the increasing focus on welded bridge members resulting in crack initiation and propagation, there is a large demand for creative solutions. One of these solutions includes the application of composite doublers over the critical weld. In order...
Blank optimization in sheet metal forming using finite element simulation
Goel, Amit
2006-04-12T23:59:59.000Z
The present study aims to determine the optimum blank shape design for the deep drawing of arbitrary shaped cups with a uniform trimming allowance at the flange i.e. cups without ears. This earing defect is caused by planar anisotropy in the sheet...
A VECTOR FINITE ELEMENT TIME-DOMAIN METHOD FOR ...
SIAM (#1) 1035 2001 Apr 10 12:32:38
2001-08-14T23:59:59.000Z
and to conserve energy and charge for arbitrary hexahedral grids. ... experiments are performed to determine the accuracy and efficiency of the method.
ARTICLE IN PRESS Finite Elements in Analysis and Design ( )
Augarde, Charles
& Resource Engineering, The University of Western Australia, Crawley Western Australia 6009, Australia
Adaptive Finite Element Method for Time ... - Purdue University
Shuhao Cao supervised under Professor Cai
2013-10-31T23:59:59.000Z
Oct 11, 2013 ... recovery-based estimator (Nicaise et al 2005) ?2. K = G(?uh) ..... Answer: No. For the same relative error 0.2, the error heat map shows that.
Finite Element Analysis of Piezoelectric Ceramic Speaker with Ansys Software
Wang, Ji
used. For many kinds of piezoelectric ceramic vibration, equivalent electric circuit analysis, such as Mason equivalent electric circuit analysis and Krimholtz equivalent electric circuit analysis,is a kind requirements, piezoelectric speaker also has been a leap development. Among the vibration mode, the bending
THERMAL PROPERTY PREDICTION VIA FINITE-ELEMENT SIMULATIONS
Fuller, Edwin R.
of gas turbine parts Optimization of k during TBC material development New lower k TBC materials materials development effort in industry has been to produce more reliable and reproducible TBC's. Knowing in advanced turbine airfoil design to allow more precise part temperature and life assessment. As physical
Least-squares finite elements and constrained evolution systems
Szypowski, Ryan
2008-01-01T23:59:59.000Z
in?nitesimal) generator of T is the linear operator A : D(and Generators Let X be a Banach space with norm X , A : D(A) ? X ? X be a lineara linear operator. Then, A is the in?nitesimal generator of
Finite Element Studies of Colloidal Mixtures Influenced by Electric Fields
Drummond, Franklin Jerrel
2011-10-21T23:59:59.000Z
.2 micrometers, 40 micrometers, and 90 micrometers from the gap center. Total force vectors were computed by integrating Maxwell and Cauchy stress tensors to determine whether the particles are pushed toward or away from the electrode gap at frequencies of 10 Hz...
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy andExsolution Enhancedenvironmental stewardshipDevelopmentFEHM
The Uranium Processing Facility (UPF) Finite Element Meshing Discussion |
Office of Environmental Management (EM)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of Energy Power.pdf11-161-LNGInternationalTechnology ValidationMilestoneDepartmentDepartment of Energy
The Uranium Processing Facility Finite Element Meshing Discussion
Office of Environmental Management (EM)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomen Owned SmallOf The 2012 Greenbuy Program. | DepartmentManagementLasSavings for1
Sandia National Laboratories: Abaqus finite-element analysis software
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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0 ResourceAwardsSafeguardsEngineers WindARPA-E ARPAe:ASMEATP3
The Finite Element Analusis of Ventilative Motorcycle Helmets.
Shen, Jhuo-ying
2008-01-01T23:59:59.000Z
??In Taiwan, a motorcycle is the most important and general transportation. It is no denying that wearing a motorcycle helmet could prevent the rider from (more)
Discontinuous Galerkin Subgrid Finite Element Method for Heterogeneous Brinkman's
Lazarov, Raytcho
made of glass or mineral wool with porosity 0.99, or open foams with porosity above 0.95, see Fig. 1 15 Fig. 1. Microstructure of industrial foams Fig. 2. Microstructure and marcostructure of mineral
Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]
2007-07-11T23:59:59.000Z
The Guide provides acceptable methods of meeting the requirements of DOE O 151.1C for programmatic elements that sustain the emergency management program and maintain the readiness of the program to respond to an emergency. Cancels DOE G 151.1-1, Volume 5-1, DOE G 151.1-1, Volume 5-2, DOE G 151.1-1, Volume 5-3, DOE G 151.1-1, Volume 5-4, DOE G 151.1-1, Volume 7-1, and DOE G 151.1-1, Volume 7-3.
Lane, R. A.; Ordonez, C. A. [Department of Physics, University of North Texas, Denton, Texas (United States)
2013-04-19T23:59:59.000Z
A computational tool is described that can be used for designing magnetic focusing or defocusing systems. A fully three-dimensional classical trajectory Monte Carlo simulation has been developed. Ion trajectories are simulated in the presence of magnetic elements that can be modeled as any combination of current loops and current lines. Each current loop or line may be located anywhere in the system and oriented along any of the three coordinate axes. The configuration need not be axisymmetric. The solutions are obtained using normalized parameters, which can be used for easily scaling the results. Examples are provided of the utility of the code.
FINITE DISJUNCTIVE PROGRAMMING CHARACTERIZATIONS ...
2010-03-07T23:59:59.000Z
In this paper, we give a finite disjunctive programming procedure to obtain .... In this paper, assuming a nonempty feasible set and bounded general integer variables ..... to find the last node ? on the path from the root node such that xk ? C?. There are two ..... http://arxiv.org/PS cache/arxiv/pdf/0707/0707.3945v1.pdf.
Finite generation conjectures for cohomology over finite fields.
Thomas H Geisser
We construct an intermediate cohmology between motivic cohomology and Weil-etale cohomology. Using this, the Bass conjecture on finite generation of motivic cohomology, and the Beilinson-Tate on the finite generation of Weil-etale cohomology are related.