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Mixed XFEM formulation for the simulation of heterogeneities including elasto‐plastic material behaviour
Author(s) -
Löhnert Stefan
Publication year - 2019
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201900270
Subject(s) - extended finite element method , finite element method , classification of discontinuities , isochoric process , materials science , mixed finite element method , isotropy , plasticity , displacement field , viscoplasticity , mechanics , structural engineering , mathematical analysis , mathematics , composite material , physics , engineering , constitutive equation , quantum mechanics , thermodynamics
Metal matrix composites often show large isochoric plastic deformations within the matrix material. For dominant plastic deformations this may lead to volumetric locking effects similar to locking in incompressible materials. Lower order mixed finite element formulations can alleviate this difficulty. Complex microstructures often require extensive effort to generate a mesh suitable for finite element simulations. The eXtended Finite Element Method may improve this situation by allowing for discontinuities in the displacement and/or strain field within any finite element. In this contribution a mixed XFEM formulation is presented combining the advantages of the XFEM and mixed FEM. The formulation is applied to small deformation elasto‐plasticity with linear isotropic and linear kinematic hardening. An example demonstrates its superior convergence behaviour compared to a standard XFEM formulation.