... most accurate beam elements in the ABAQUS ... The beam finite element representation is shown in ... The elements of the finite element representation ...
DTIC Science & Technology
... The finite-element method is very powerful and flexible to model complex ... the region of interest can be subdivided into finite elements accurately. ...
This report combines two ideas from the basis of finite volume and finite element numerical methods to form a accurate discontinuous finite element solution for the two dimensional Euler equations.
Energy Citations Database
The finite element method is applied to several simple cases of steady flow of a perfect, incompressible fluid. It is shown that the finite element representation accurately reflects the behavior of the classical flow equations. Finite elements form the ...
National Technical Information Service (NTIS)
This paper develops and analyses individual construction aspects of an efficient and accurate finite
NASA Technical Reports Server (NTRS)
... ABAQUS/STANDARD 6.1 (Hibbitt, Karlsson & Sorensen Inc ... elements are needed to obtain an accurate ... A three-dimensional finite element study,� J ...
... finite element program ABAQUS. These elements are specially configured to accurately predict interface stresses in adhesively bonded joints and ...
performance of the structures and efficient techniques for determining ... thermal stress distributions including critical stress locations accurately. ... the improved finite elements are demonstrated by'both academic and ...
NASA Website
Saturated groundwater flow can often be described by the law of mass conservation and Darcy's law, i.e. by a potential flow problem. An accurate approximation of the specific discharge can be determined by the mixed finite element method. In this article ...
... Abstract : The objective of this research project was to derive and evaluate accurate and efficient numerical solution algorithms for the three ...
... It should therefore be possible to approximate the solution accurately using the Rayleigh-Ritz Galerkin method with a piecewise polynomial ...
... shocks are allowed to develop freely. Rankin-Hugoniot conditions are satisfied accurately. Although this method is efficient ...
... mesh generation is straightforward. In addition, it allows modeling floating objects and tank baffles with no additional effort. ...
... This HEN procedure controls the crack growth rate in the finite element model by following the experimental displacement rates accurately. ...
... Pagination or Media Count : 111. Abstract : In structural dynamics the ability of a finite element model, or (FEM), to accurately represent a structure's ...
An unconditionally stable second order accurate implicit-implicit staggered procedure for the finite
Cracked geometries were studied by finite element techniques with the aid of a new special element embedded at the crack tip. This model seeked to accurately represent the singular stresses and strains associated with the elasto-plastic flow process. The ...
In the finite element method for structural analysis, it is generally necessary to discretize the structural model into a very large number of elements to accurately evaluate displacements, strains, and stresses. As the complexity of the model increases, ...
crack tip to a point of interest h u x = XFEM displacement approximation Iu = nodal degree of freedom is accurately represented. The extended finite element method (XFEM) along with the level set method can be used algorithm are compared. M #12;3 II. Extended Finite Element Method The extended ...
E-print Network
Comparison of the propagation-eigen-function element, the stationary-eigen-function element, and the quarter-point isoparametric element in terms of accuracy and efficiency leads to several conclusions. The two eigen-function elements showed similar accur...
NASA Technical Paper 3608. Highly Accurate Beam Torsion. Solutions Using the p-Version Finite. Element Method. James Smith. Lyndon B. Johnson Space ...
We present a Neumann-subproblem a posteriori finite element procedure for the efficient and accurate calculation of rigorous, 'constant-free' upper and lower bounds for sensitivity derivatives of functionals of the solutions of partial differential equati...
... which is entitled "High-Order Taylor-Galerkin and Adaptive hp ... of high-order adaptive finite element methods for ... size h and the local spectral order p ...
The finite element method and an explicit time stepping algorithm which is based on Taylor-Galerkin schemes with an appropriate artificial viscosity is combined with an automatic mesh refinement process which is designed to produce accurate steady state s...
In structural dynamics the ability of a finite element model, or (FEM), to accurately represent a structure's dynamic response (natural frequencies and mode shapes) determines its utility as a solution tool. Often the model needs to be updated or improved...
A reduced quadratic finite element method on quadrilaterals is developed for discretizing the capillary equation in regular and irregular domains. Newton's method is used to solve the resulting set of nonlinear equations for the capillary surface. Numerical experiments are conducted for square and elliptical capillaries in order to compare this ...
DOE Information Bridge
... IN THE FINITE ELEMENT METHOD IIvo ... Page 3. ON LOCKING AND ROBUSTNESS IN THE FINITE ELEMENT METHOD by ...
... Micro-mechanics; Constitutive behavior; Finite element modeling; Buckling; Specimen geometry ... produced in thin foils and small cubes or cylinders ...
... XT3 was approximately twice as fast as the 03K, 4. the GMRES ... the most accurate solution, 5. the successive over-relaxation PC performed much ...
... Structural models using finite element theory often need to be adjusted so they can accurately simulate the real structure. ...
The use of simplified error models to accurately simulate and evaluate the performance of an optical
mized with respect to a certain norm. For systems with non-symmetric operators ...... Webelieve that, with the recent advances in the development of Petrov- ...
The mapping methods consist of: (1) deterministic structural analyses with fine (convergent) finite element meshes, (2) probabilistic structural analyses ...
... analytic calculations and finite element simulations. ... reduce sensor coherence over a broad spectral ... order accurate continuous Galerkin method for ...
... Because formal mathematical solutions of such complex large-scale modeling problems are impractical, approximate but accurate solutions are ...
... markers for the multimodal data (PET and MRI). ... a finite element algorithm for compression simulation ... approach was unique in the sense it permitted ...
A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite ...
NASA Astrophysics Data System (ADS)
Project 91260 High-Frequency (HF) Antenna Element Modeling is a MITRE sponsored research project to develop computer programs and accurate models for predicting the element pattern, radiation efficiency, and input impedance of HF monopole elements on grou...
A coupled boundary element (BEM)-finite element (FEM) approach is presented to accurately model structure-acoustic interaction systems. The boundary element method is first applied to interior, two and three-dimensional acoustic domains with complex geome...
Many of the current radiosity algorithms create a piecewise constant approximation to the actual radiosity. Through interpolation and extrapolation, a continuous solution is obtained. An accurate solution is found by increasing the number of patches which describe the scene. This has the effect of increasing the computation time as well as the memory requirements. By using ...
A new method for the simulation of incompressible diphasic flows in two dimensions is presented, the distinctive features of which are: (1) reformation of the basic equation and specific choices of the finite element approximation of the same; (11) use of a mixed finite elements method, approximating both scalar ...
In practical damage tolerance analyses of jet engines, a simple, reliable, accurate, fast finite element code with good pre- and post-processing capability and with a full 3-D fracture mechanics capability, is required. The general finite element code NIS...
preserve the data structure of the finite element method. If accurate non�reflecting boundary conditions, the proposed local boundary conditions preserve the data structure of the finite element method and require condition coupling all points on the artificial boundary \\Gamma 1 . When ...
The increased power of computers and computer codes makes the use of nonlinear dynamic finite element analyses attractive for use as a tool used in the design and certification of radioactive material transportation packages. For this analysis technique to be acceptable it must be demonstrated. The technique has the ability to ...
Mapping methods are developed to improve the accuracy and efficiency of probabilistic structural analyses with coarse finite element meshes. The mapping methods consist of the following: (1) deterministic structural analyses with fine (convergent) finite ...
A mesoscale model capable of treating variable terrain is described herein. The model, based on the hydrostatic and anelastic approximations, has been developed with a primary goal of providing, in real time, physically realistic and accurate wind fields ...
A study has been performed to quantify the accuracy of linear triangular finite elements for modeling temperature and stress fields in structures with multiple holes. The purpose of the study was to evaluate the use of these elements for the analysis of HTGR fuel blocks, which may contain up to 325 holes. Since an ...
We investigate (via finite-element analyses) the factors that may affect the accuracy of micro-compression measurements. Based on these simulations, we suggest guidelines for the development of accurate micro- compression experiments in terms of fillet to...
A boundary finite element method for the accurate and efficient modeling of global circuit behavior in VLSI (Very Large Scale Integration) layout is presented. This method consists of three important parts: the determination of Green's function, the use o...
A user-defined subroutine has been developed to implement special 2-D and 3-D layered continuum elements in the commercial finite element program ABAQUS. These elements are specially configured to accurately predict interface stresses in adhesively bonded...
The solution to the Helmholtz equation, encountered in nuclear reactor theory, is obtained with the finite element technique, employing linear and quadratic Lagrange and cubic Hermite interpolation polynomials, and compared with the classical finite difference result. Transforming the Helmholtz equation into a weak form, the ...
Using the regular finite element method for analyzing wave propagation problems presents difficulties: (a) The finite element mesh gives spurious reflection of the traveling wave and (b) Since a finite element model has to have a finite boundary, the ...
A study for validating a time-accurate explicit finite element code for modeling fully-coupled flexible multibody systems carrying liquid-filled tanks is presented. The multibody system includes rigid bodies, flexible bodies, joints, and actuators. Rigid ...
A finite element field solver for dipole modes in axisymmetric structures has been written. The second-order elements used in this formulation yield accurate mode frequencies with no spurious modes. Quasi-periodic boundaries are included to allow travelling waves in periodic structures. The solver is useful in ...
... Title : An Investigation of the Method of Finite Elements with Accuracy Comparisons to the Method of Finite Differences for Solution of the Transient ...
A finite element model of turbulent motion and diffusiom in the atmospheric planetary boundary layer is presented. In preliminary results the behavior of the planetary boundary layer agrees well with the available data. The proposed simple model is more economical and efficient than the complicated existing finite difference models ...
A general criterion for testing a mesh with topologically similar repeat units is given, and the analysis shows that only a few conventional element types and arrangements are, or can be made suitable for computations in the fully plastic range. Further, ...
Axisymmetric, ideal MHD configurations with steady flow are computed by applying the finite element method. Rectangular elements with four to eight nodes are used. By mesh rearrangement the equilibria are obtained in flux coordinates. Accurate results wit...
Accurate formulations based on finite-element methods are developed for calculating radiant heat transfer among diffuse-gray surfaces in an enclosure. The method of Gebhart is compared with solutions of the rigorous integral equations using these formulations. A Swartz-Wendroff approximation applied to the finite-element ...
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 ...
The utility of the finite-element Galerkin technique in advection-diffusion flow problems is examined by comparison with several finite-difference schemes in one dimension. The calculations show that for relatively coarse grids, finite-element solutions are either comparable to or significantly better than those obtained from the ...
The present discussion of global and linear stability theories for buoyancy-driven flows formulates eigenvalue problems yielding critical Rayleigh number values in variational form, en route to a construction of penalty-finite element approximations of these problems. The penalty-finite element formulation is ...
finite element (FE) method and meshless local Petrov-Galerkin. (MLPG) method for analyzing ..... numerical integration that may be needed to integrate accurately ... rule is used for the quadratic elements in the. FE region. The Gauss quadrature ... method are compared to exact solutions wherever available. ...
... Title : APPLICATIONS OF THE HYBRID FINITE ELEMENT - BOUNDARY ELEMENT METHOD IN ELECTROMAGNETICS. Corporate Author : ...
... Title : Finite Element, Finite Difference, and Finite Volume Methods: Examples and their Comparisons. Descriptive Note : Final rept. Jan-Jul 95,. ...
... Noise, Vibration, Boundary clement, Finite ... STRUCTURES, BOXES, BOUNDARIES, STRUCTURAL ... INTENSITY, FINITE ELEMENT ANALYSIS ...
The probabilistic finite element method (PFEM), which is a combination of finite element methods and
... PRESSURE STABILIZED BEAM FINITE ELEMENT -- 6 PERFORMING ORG. ... PRESSURE STABILIZED BEAM FINITE ELEMENT INTRODUCTION ...
A discussion of the finite element method for solving elliptic systems and an open problem suggested by the construction of finite elements.
NSDL National Science Digital Library
... Title : Integration of a Constitutive Equation Based Finite Element for Compositive Materials into a Commercial Finite Element Software Code. ...
... isoparametric finite elements with a ... RELATIONS, FINITE ELEMENT ANALYSIS, NUMERICAL ... ELASTIC PROPERTIES, PLASTIC PROPERTIES ...
... current and cancelled), Joint Staff and ... Title : FINITE ELEMENT MODELING OF THE FIBER ... USING THE ABAQUS FINITE ELEMENT PROGRAM. ...
... of adaptive finite element methods, the ... of parameters in degenerate partial differential equations. ... problems, adaptive finite elements are particularly ...
... The finite element models for the staggered vertical grids did not perform up to their possibilities due to the boundary elements. ...
In this talk the authors present a highly accurate coarsening algorithm for constructing coarse finite element spaces to be used in algebraic multigrid methods designed for finite element problems on generally unstructured meshes. The new algorithm relies on removing certain percentage of the ...
Accurate and reliable electromagnetic modeling codes, which may be specific or general purpose, help Lawrence Livermore National Laboratory carry out its research. However, a need for a three-dimensional coded prompted the development of a finite element code. MAXWELL3 is a general electromagnetic modeling code (solves the differential ...
In an economically competitive industrial setting, it is advantageous to generate accurate engineering analysis results as rapidly as possible in order to minimize the design cycle time. For many structural problems, the goal of the computational analysis is to obtain the stress field. The standard tool for obtaining the stress field is the finite-element ...
Elementary descriptions of finite element and finite difference methods are given while the finite volume method is briefly overviewed. Examples illustrating finite element and finite difference methods are worked out. Finally, comparisons of these ...
