Search results for "Finite element method"
showing 10 items of 746 documents
Numerical methods for nonlinear inverse problems
1996
AbstractInverse problems of distributed parameter systems with applications to optimal control and identification are considered. Numerical methods and their numerical analysis for solving this kind of inverse problems are presented, main emphasis being on the estimates of the rate of convergence for various schemes. Finally, based on the given error estimates, a two-grid method and related algorithms are introduced, which can be used to solve nonlinear inverse problems effectively.
A parallel splitting up method and its application to Navier-Stokes equations
1991
A parallel splitting-up method (or the so called alternating-direction method) is proposed in this paper. The method not only reduces the original linear and nonlinear problems into a series of one dimensional linear problems, but also enables us to compute all these one dimensional linear problems by parallel processors. Applications of the method to linear parabolic problem, steady state and nonsteady state Navier-Stokes problems are given. peerReviewed
Studies on predictive virtual models based on finite element analysis of the behaviour of geomembranes
2017
The study shown in this paper presents the behaviour of geomembranes used at the ecological landfills. For this goal was used a method designed to elaborate the virtual models of 3D geomembrane with one ply or 2 plies disposed at 30°, 45° and 90° and based on this model there were developed a number of 20 particular cases. For each situation it was realized the nonlinear analyses for all the developed cases with different vertical pressures representing different loads for the waste layer (1m, 2m, 10m, 15m, 20m). The main results are obtained in graphical form and represent the Maximum tensions Von Mises and total displacements of the geomembrane.
finite element methods
2017
Two robot patch recovery methods with built-in field equations and boundary conditions superconvergence similarities in standard and mixed finite element methods on the FEM for the Navier-Stokes equations in the domains with corner singularities projections in finite element analysis and application element analysis method and superconvergence quadratic interpolation polynomials in vertices of strongly regular triangulations explicit error bounds for a nonconforming finite element method analysis of the average efficiency of an error estimator on the mesh for difference schemes of higher accuracy for the heat-conduction equation shape design sensitivity formulae approximated by means of a r…
MAST-2D diffusive model for flood prediction on domains with triangular Delaunay unstructured meshes
2011
Abstract A new methodology for the solution of the 2D diffusive shallow water equations over Delaunay unstructured triangular meshes is presented. Before developing the new algorithm, the following question is addressed: it is worth developing and using a simplified shallow water model, when well established algorithms for the solution of the complete one do exist? The governing Partial Differential Equations are discretized using a procedure similar to the linear conforming Finite Element Galerkin scheme, with a different flux formulation and a special flux treatment that requires Delaunay triangulation but entire solution monotonicity. A simple mesh adjustment is suggested, that attains t…
FINITE ELEMENT APPROXIMATION OF NONLOCAL HEAT RADIATION PROBLEMS
1998
This paper focuses on finite element error analysis for problems involving both conductive and radiative heat transfers. The radiative heat exchange is modeled with a nonlinear and nonlocal term that also makes the problem non-monotone. The continuous problem has a maximum principle which suggests the use of inverse monotone discretizations. We also estimate the error due to the approximation of the boundary by showing continuous dependence on the geometric data for the continuous problem. The final result of this paper is a rigorous justification and error analysis for methods that use the so-called view factors for numerical modeling of the heat radiation.
A thermodynamically consistent nonlocal formulation for damaging materials
2002
A thermodynamically consistent nonlocal formulation for damaging materials is presented. The second principle of thermodynamics is enforced in a nonlocal form over the volume where the dissipative mechanism takes place. The nonlocal forces thermodynamically conjugated are obtained consistently from the free energy. The paper indeed extends to elastic damaging materials a formulation originally proposed by Polizzotto et al. for nonlocal plasticity. Constitutive and computational aspects of the model are discussed. The damage consistency conditions turn out to be formulated as an integral complementarity problem and, consequently, after discretization, as a linear complementarity problem. A n…
Acute Type Refinements of Tetrahedral Partitions of Polyhedral Domains
2001
We present a new technique to perform refinements on acute type tetrahedral partitions of a polyhedral domain, provided that the center of the circumscribed sphere around each tetrahedron belongs to the tetrahedron. The resulting family of partitions is of acute type; thus, all the tetrahedra satisfy the maximum angle condition. Both these properties are highly desirable in finite element analysis.
Mixed mode failure analysis of bonded joints with rate dependent interface models
2006
The recent developments in joining technologies and the increasing use of composites materials in structural design justify the wide interest of structural mechanics researchers in bonded joints. Joints often represent the weakness zone of the structure and appropriate and rigorous mechanical models are required in order to describe deformation, durability and failure. The present work is devoted to the theoretical formulation and numerical implementation of an interface model suitable to simulate the time-dependent behaviour of bonded joints. The interface laws are formulated in the framework of viscoplasticity for generalized standard materials and describe the softening response of the j…
On the numerical solution of axisymmetric domain optimization problems by dual finite element method
1994
Shape optimization of an axisymmetric three-dimensional domain with an elliptic boundary value state problem is solved. Since the cost functional is given in terms of the cogradient of the solution, a dual finite element method based on the minimum of complementary energy principle is used. © 1994 John Wiley & Sons, Inc.