Showing papers in "Computer Methods in Applied Mechanics and Engineering in 1994"

TL;DR: In this paper, an extension of the particle-in-cell method is proposed, in which particles are interpreted to be material points that are followed through the complete loading process and a fixed Eulerian grid provides the means for determining a spatial gradient.

TL;DR: In this paper, a modified variational principle is used to replace the Lagrange multipliers at the outset by their physical meaning so that the discrete equations are banded, and weighted orthogonal basis functions are constructed so the need for solving equations at each quadrature point is eliminated.

TL;DR: In this paper, the Dirichlet problem for a class of elliptic operators was solved by a Lagrange multiplier/fictitious domain method, allowing the use of regular grids and therefore of fast specialized solvers for problems on complicated geometries; the resulting saddle point system can be solved by an Uzawa/conjugate gradient algorithm.

TL;DR: In these mesh update strategies, based on the special and automatic mesh moving schemes, the frequency of remeshing is minimized to reduce the projection errors and to minimize the cost associated with mesh generation and parallelization set-up.

TL;DR: This paper shows that the mathematical treatment of the floating subdomains and the specific conjugate projected gradient algorithm that characterize the FETI method are equivalent to the construction and solution of a coarse problem that propagates the error globally, accelerates convergence, and ensures a performance that is independent of the number ofSubdomains.

TL;DR: In this article, a fictitious domain method for the numerical solutions of three-dimensional elliptic problems with Dirichlet boundary conditions and also of the Navier-Stokes equations modeling incompressible viscous flow was discussed.

TL;DR: In this article, a second order linear scalar differential equation including a zero-th order term is approximated using first the standard Galerkin method enriched with bubble functions, and then the method is generalized to allow for a convection operator in the equation.

TL;DR: In this paper, a computational procedure is developed for predicting separated turbulent flows in complex two-dimensional and three-dimensional geometries, based on the fully conservative, structured finite volume framework within which the volumes are non-orthogonal and collocated such that all flow variables are stored at one and the same set of nodes.

TL;DR: In this article, a new four-node shell element for nonlinear analysis which is useful for explicit time integration with single point quadrature is presented, and an assumed strain method is used to stabilize the zero-energy modes of the element.

TL;DR: In this article, the least square finite element method (LSFEM) based on the velocity-pressure-vorticity formulation is applied to large-scale/three-dimensional steady incompressible Navier-Stokes problems.

TL;DR: In this article, a finite element formulation is developed for the analysis of the inhomogeneous macroscopic deformations of metal forming, and anisotropic material properties are derived from a microscopic description based on polycrystal plasticity theory.

TL;DR: In this paper, large-scale flow simulation strategies involving implicit finite element formulations are described in the context of incompressible flows, and a stabilized space-time formulation for problems involving moving boundaries and interfaces is presented, followed by a discussion of mesh moving schemes.

TL;DR: In this paper, a finite element formulation for solving the compressible Navier-Stokes equations is presented, which accommodates the use of any set of variables, including primitive variables (p, u, T ), or entropy variables.

TL;DR: It is demonstrated that, with these new computational capabilities, today the research group is at a point where it routinely solve practical flow problems, including those in 3D and those involving moving boundaries and interfaces.

TL;DR: In this article, the quality of a posteriori error estimator for finite element approximations of linear elliptic problems is evaluated using asymptotic properties of error estimators in the interior of patchwise uniform grids of triangles.

TL;DR: A subclass of algorithms which retain these strong notions of nonlinear stability and long-term dissipative behavior is identified which, in addition, has the remarkable property of being linear within the time step.

TL;DR: In this paper, the interior elastoacoustic problem is solved by a finite element method, which does not present spurious or circulation modes for nonzero frequencies, and consists of classical triangular lagrangian elements for the solid and lowest order triangular Raviart-Thomas elements for fluid.

TL;DR: The method uses the space-time formulation by Godunov while the discretization is conducted on non-structured tetrahedral meshes, using Roe's approximate Riemann solver, an implicit time stepping and a MUSCL-type interpolation.

TL;DR: In this paper, the authors describe massively parallel finite element computations of unsteady incompressible flows involving fluid-body interactions, based on the Deforming-Spatial-Domain/Stabilized-Space-Time (DSD/SST) finite element formulation.

TL;DR: In this paper, a thermomechanical contact formulation is derived based on a sophisticated interface model, which includes constitutive equations for the contact stresses, the contact heat flux and the frictional dissipation.

TL;DR: In this paper, the authors present a consistent theoretical framework for a novel stress resultant geometrically nonlinear shell theory, which is the main feature of the present shell theory development, which stands in contrast with the classical developments in the shell theory.

TL;DR: It is proved that under mild assumptions, the new norm is, asymptotically, equivalent to the product space norm for the Navier-Stokes equations; moreover, by summing the solutions of local elliptic residual problems, the computed global error is shown to be always bounded below by the true global error when measured in the newnorm.

TL;DR: Several algorithmic advances are presented which significantly enhance the scalability of this approach, including: implementation of an advanced combine operation for degrees-of-freedom on subdomain edges, parallel solution of the (fine-grained) coarse-grid problem, and implementation of local low-order finite element preconditioners for the find- grid problem.

TL;DR: In this paper, an adaptive spectral method was developed for the efficient solution of time dependent partial differential equations for driven flow in a cavity, where sharp gradients, singularities, and regions of poor resolution were resolved optimally as they developed in time using error estimators which indicate the choice of refinement to be used.

TL;DR: A methodology for extending the range of applications of domain decomposition methods to problems with multiple or repeated right hand sides as a series of minimization problems over K-orthogonal and supplementary subspaces and tailor the preconditioned conjugate gradient algorithm to solve them efficiently is presented.

TL;DR: Galerkin/least-squares/gradient least squares as discussed by the authors is a new variation of the Galerkin method, designed to provide exact nodal amplification factors, offering accurate solutions at any resolution.

TL;DR: In this article, a computational method is developed in order to analyze a class of fluid-structure interaction problems, where the viscous incompressible fluid and a rigid body-spring system interact nonlinearly with each other.

TL;DR: In this paper, a post processor is described which allows the calculation of the crack initiation conditions from the history of strain components taken as the output of a finite element calculation, based upon damage mechanics using coupled strain damage constitutive equations.

TL;DR: In this article, a new family of implicit, single-step time integration methods is presented for solving structural dynamics problems, which are unconditionally stable, second-order accurate and asymptotically annihilating.