On configurational forces for gradient-enhanced inelasticity
Journal article, 2018

In this paper we discuss how configurational forces can be computed in an efficient and robust manner when a constitutive continuum model of gradient-enhanced viscoplasticity is adopted, whereby a suitably tailored mixed variational formulation in terms of displacements and micro-stresses is used. It is demonstrated that such a formulation produces sufficient regularity to overcome numerical diffi- culties that are notorious for a local constitutive model. In particular, no nodal smoothing of the internal variable fields is required. Moreover, the pathological mesh sensitivity that has been reported in the literature for a standard local model is no longer present. Numerical results in terms of config- urational forces are shown for (1) a smooth interface and (2) a discrete edge crack. The corresponding configurational forces are computed for different values of the intrinsic length parameter. It is concluded that the convergence of the com- puted configurational forces with mesh refinement depends strongly on this parameter value. Moreover, the convergence behavior for the limit situation of rate-independent plasticity is unaffected by the relaxation time parameter

Configurational forces

Gradient plasticity

Mixed formulation

Author

Dimosthenis Floros

Chalmers, Industrial and Materials Science, Material and Computational Mechanics

Fredrik Larsson

Chalmers, Industrial and Materials Science, Material and Computational Mechanics

Kenneth Runesson

Chalmers, Industrial and Materials Science, Material and Computational Mechanics

Computational Mechanics

0178-7675 (ISSN) 1432-0924 (eISSN)

Vol. 61 409-432

Subject Categories

Applied Mechanics

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1007/s00466-017-1460-x

More information

Latest update

12/18/2018