Finite element implementation of gradient plasticity models - Part II: Gradient-dependent evolution equations

The variational formulation and finite element implementation of a class of plasticity models with gradient-dependent yield functions is covered in detail in Part I. In this sequel, attention is focussed upon the finite element formulation and implementation of a different class of plasticity models wherein spatial gradients of one or more internal variables enter the evolution equations for the state variables. Finite element solutions are obtained for the problems of localization of plastic flow in plane strain tension and of a mode-I plane strain crack. The pathological dependence of the finite element solution on the size of the elements in local plasticity models disappears when the gradient-type model is used. (C) 1998 Elsevier Science S.A. All rights reserved.