A regularization framework for damage-plasticity models via gradient enhancement of the free energy

We present a framework for the regularization of coupled damage-plasticity models through gradient enhancement of the Helmholtz-free-energy function. This enhancement is achieved introducing new variables, coupled to the gradients of the inelastic variables and thus regularizing the model. The variational formulation of the model results in a pure minimization problem. Numerical examples, which show the performance of the proposed gradient-enhanced model, are presented. It is shown that the pathological mesh dependence of the coupled inelastic model is efficiently removed, together with the difficulties of numerical calculations in the softening range. Copyright (C) 2009 John Wiley & Sons, Ltd.