Stable Generalized Finite Element Method and associated iterative schemes; application to interface problems

Kenan Kergrene, Ivo Babuška, Uday Banerjee

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

The Generalized Finite Element Method (GFEM) is an extension of the Finite Element Method (FEM), where the standard finite element space is augmented with a space of non-polynomial functions, called the enrichment space. The functions in the enrichment space mimic the local behavior of the unknown solution of the underlying variational problem. GFEM has been successfully applied to a wide range of problems. However, it often suffers from bad conditioning, i.e., its conditioning may not be robust with respect to the mesh and in fact, the conditioning could be much worse than that of the standard FEM. In this paper, we present a numerical study that shows that if the "angle" between the finite element space and the enrichment space is bounded away from 0, uniformly with respect to the mesh, then the GFEM is stable, i.e., the conditioning of GFEM is not worse than that of the standard FEM. A GFEM with this property is called a Stable GFEM (SGFEM). The last part of the paper is devoted to the derivation of a robust iterative solver exploiting this angle condition. It is shown that the required "wall-clock" time is greatly reduced compared to popular GFEMs used in the literature.

Original languageEnglish (US)
Pages (from-to)1-36
Number of pages36
JournalComputer Methods in Applied Mechanics and Engineering
Volume305
DOIs
StatePublished - Jun 15 2016

Keywords

  • Angle condition
  • Condition number
  • Generalized Finite Element Method (GFEM)
  • Partition of Unity Method (PUM)
  • Stable GFEM (SGFEM)

ASJC Scopus subject areas

  • Computer Science Applications
  • Computational Mechanics
  • Mechanics of Materials
  • Mechanical Engineering
  • Physics and Astronomy(all)

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