An Expression of Elastic-Plastic Constitutive Law Incoporating Stress Increment Dependence : Initial Isotropic Material with Mises-Type Plastic Potential

Abstract

A constitutive law for elastic-plastic materials is presented on the assumption that the deviatoric stress increments affect plastic strain increments. By the use of weighing parameters, the law is expressed as an averaging rule of the usual plastic potential law (J₂-flow rule) and a rule which permits plastic strain increments to depend only on stress increments. The developed law allows the existence of a vertex on the yield surface. It can, however, be expressed formally in the same equation as the usual J₂-flow rule, which implies that it is applicable to such a solution scheme as the finite element method.