Finite element analysis of finite strain micromorphic Drucker-Prager plasticity

Abstract

Earlier, Isbuga and Regueiro (2011) and Regueiro and Isbuga (2011) presented three dimensional finite element analysis of finite strain micromorphic isotropic elasticity based on the approach of Eringen and Suhubi (1964). We present the extension of this work to plasticity, following the formulation of Regueiro (2009, 2010) and Isbuga (2012). We assume the existence of an intermediate configuration and apply the separate multiplicative decomposition of the deformation gradient tensor and the micro-deformation tensor. In this paper, we investigate the effect of elastic length scale together with the boundary layer effect on micro-displacement tensor field for uniaxial strain and plane strain conditions, involving elastoplasticity with a Drucker-Prager yield function. We emphasize the importance of the additional degrees of freedom introduced by the micromorphic continuum formulation.