Crack Propagation by Element-Free Galerkin Methods

Abstract

The element-free Galerkin (EFG) method is a mesh-free method for solving solid mechanics problems with an approximation based only on nodes. It is developed here for linear elastic fracture problems. Smoothing of mesh-free approximations near nonconvex boundaries is done by three methods: (1) the diffraction method, in which the nodal domain of influence wrapped a short distance around a boundary, (2) the transparency method, which is described only for cracks, yields continuous approximations by gradually severing the domains of influence near crack tips, and (3) the 'see-through' method, or continuous line criterion, which does not enforce a discontinuity or crack if the tip is within the domain of influence. Two methods for enriching EFG approximations for linear elastic fracture problems are described: extrinsic enrichment involves adding the form of the solution to the trial function; for intrinsic enrichment, the EFG basis is expanded to include terms from the near tip crack solution. Several problems are solved to illustrate the effectiveness of EFG crack propagation with smoothing and enrichment.

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Document Details

Document Type
Technical Report
Publication Date
May 15, 1997
Accession Number
ADA329723

Entities

People

  • Ted Belytschko

Organizations

  • Northwestern University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Algorithms
  • Applied Mechanics
  • Boundaries
  • Computational Fluid Dynamics
  • Computational Science
  • Coordinate Systems
  • Crack Propagation
  • Crack Tips
  • Fracture (Mechanics)
  • Galerkin Method
  • Geometry
  • J Integrals
  • Materials Science
  • Mathematics
  • Mechanics
  • Modulus Of Elasticity
  • Numerical Analysis

Readers

  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Structural Health Monitoring of Composite Structures.