Showing papers in "Computer Methods in Applied Mechanics and Engineering in 1998"

TL;DR: In this article, a general treatment of the variational multiscale method in the context of an abstract Dirichlet problem is presented, showing how the exact theory represents a paradigm for subgrid-scale models and a posteriori error estimation.

TL;DR: In this article, a variational iteration method is used to give approximate solutions of the problem of seepage flow in porous media with fractional derivatives, and the results show that the proposed iteration method, requiring no linearization or small perturbation is very effective and convenient.

TL;DR: An alternate method based on Fourier series which avoids meshing and which makes direct use of microstructure images is proposed, based on the exact expression of the Green function of a linear elastic and homogeneous comparison material.

TL;DR: The software system developed provides an integrated set of tools to solve clinically relevant blood flow problems and test hypotheses regarding hemodynamic factors in vascular adaptation and disease and the validity of the computational method was established.

TL;DR: This paper considers the realistic situation where the fluid and structure subproblems have different resolution requirements and their computational domains have non-matching discrete interfaces, and addresses the proper discretization of the governing interface boundary conditions.

TL;DR: In this paper, an accurate homogenization method that accounts for large deformations and viscoelastic material behavior on microscopic and macroscopic levels is presented, assuming local spatial periodicity of the microstructure.

TL;DR: In this article, a new iteration method is proposed to solve nonlinear problems with convolution product nonlinearities and the results reveal that the approximations obtained by the proposed method are uniformly valid for both small and large parameters in non-linear problems.

TL;DR: It is shown that the classical SUPG method is very similar to an explicit version of the Characteristic-Galerkin method, whereas the Taylor-Galerskin method has a stabilization effect similar to a sub-grid scale model, which is in turn related to the introduction of bubble functions.

TL;DR: In this paper, the authors proposed a method to control the arbitrary motion of two-dimensional dynamic unstructured fluid grids with additional torsional springs, which can be designed to prevent the interpenetration of neighboring triangles.

TL;DR: In this article, a hybrid computational method for solving boundary value problems is introduced which combines features of the meshless hp-cloud methods with features of conventional finite elements, and it admits straightforward nonuniform hp-type approximations, easy implementation of essential boundary conditions, is robust under severe distortions of the meshes, and can deliver exponential rates of convergence.

TL;DR: In this paper, a non-probabilistic, interval modeling of uncertain-but-non-random parameters for structures is developed for antioptimization analysis, consisting in determining the least favorable responses.

TL;DR: A system that helps automate the task of writing efficient portable unstrucmred mesh solvers for distributed memory parallel supercomputers and indicates that, despite the highly irregular structure of the problem, excellent performance and scalability are achieved.

TL;DR: In this paper, a transient-gradient enhanced damage model was developed for numerical modeling of the damage and fracture process within a continuum damage mechanics framework, which assumes a direct coupling between the material length parameter and the local strain state of the material, which leads to a transient behaviour of the nonlocal effect.

TL;DR: The Berenger perfectly matched layer (or PML) is used in computational electromagnetism as a sponge layer to terminate finite element approximations of scattering problems.

TL;DR: In this paper, the concept of the so-called "artificial or balancing diffusion" used to stabilize the numerical solution of advective-diffusive transport and fluid flow problems is revised.

TL;DR: In this article, a new class of finite element methods is proposed for the solution of frictionless dynamic contact of solids that exhibit the same conservation laws as the underlying continuum dynamical system.

TL;DR: In this paper, the authors extended well-known upwind schemes for hyperbolic equations to solve the two-dimensional Saint-Venant (or shallow water) equations and compared the resulting schemes in terms of a conservation property.

TL;DR: The objective of this paper is to investigate the efficiency of combinatorial optimization methods, in particular algorithms based on evolution strategies (ES) when incorporated into the solution of large-scale, continuous or discrete, structural optimization problems.

TL;DR: In this paper, a numerical model is developed for the simulation of the 3D deformations of skeletal muscles based on a generalization of the model proposed by Humphrey and Yin for the passive behavior of cardiac muscle.

TL;DR: A globally conservative Galerkin/least-squares formulation which attains correct shock structure is developed for any choice of variables in this article, where the choice of entropy variables satisfies exactly the discrete Clausius-Duhem inequality without any dissipative mechanisms, whereas for the rest of the variables, artificial diffusion is required to guarantee entropy production.

TL;DR: In this paper, a constitutive framework for the elasto-viscoplastic response of metals that utilizes polycrystal plasticity is presented together with a corresponding numerical integration procedure, where single crystal equations are written in an intermediate configuration obtained by elastically unloading the deformed crystal without rotation from the current configuration to a stress-free state.

TL;DR: A Lagrange multiplier based substructuring method for solving iteratively large-scale systems of equations arising from the finite element discretization of static and dynamic plate bending problems, essentially an extension of the FETI domain decomposition algorithm to fourth-order problems.

TL;DR: In this article, the hydraulic properties of a random porous medium are modeled as spatial random processes and the concentrations over the whole domain are also random processes, with unknown probabilistic structure.

TL;DR: In this article, an investigation of time marching computational fluid-structure interaction algorithms is presented, where the influence of the time lag between the integration of the fluid and structure is investigated by comparison of different predictions for the structure.

TL;DR: In this paper, the use of genetic algorithm (GA) optimization, a global search technique, is used to determine both the active control and passive mechanical parameters of a vehicle suspension system.

TL;DR: High-order finite difference methods for solving the Helmholtz equation are developed and analyzed, in one and two dimensions on uniform grids, and a symmetric high-order representation is developed for a Neumann boundary condition.

TL;DR: In this paper, an implicit method devoted to frictional contact problems has been implemented in a dynamical deep drawing simulation software (SIMEM3 Renault) where unilateral contact and dry friction is assumed between the metal sheet and the tools.

TL;DR: In this paper, a symmetric Galerkin boundary element method is developed for the analysis of linearly elastic, isotropic three-dimensional solids containing fractures, and a special crack-tip element is developed which has a novel feature in that there exist degrees of freedom associated with the nodes at the crack front.

TL;DR: In this paper, a modified version of the Cam-Clay model of critical state soil mechanics is reformulated to include finite deformation effects, which is appropriate for cases involving large plastic volumetric strains, and the use of a class of two-invariant stored energy functions.

TL;DR: In this paper, the steady-state form of the equations is considered in a weak form using a Lagrange multiplier, and a general class of hp-adaptive FE approximations for affine elements is presented.