KINEMATIC HARDENING RULES IN FINITE PLASTICITY .1. A CONSTITUTIVE APPROACH

Plasticity laws exhibiting non-linear kinematic hardening are consider ed within the framework of infinitesimal deformations. The evolution e quations governing the response of kinematic hardening are derived as sufficient conditions in order for the intrinsic dissipation inequalit y to be satisfied in every process. With a view to the extension to fi nite deformations, two basic possibilities are proposed. In every case , an isotropic elasticity law with respect to the so-called plastic in termediate configuration is assumed to hold. The theory applicable to finite deformations is based on the concept of so-called dual variable s and associated time derivatives. Thus, the main difference between t he present work and other contributions in this area is the choice of the variables used to formulate the theory. In fact, using dual variab les, hardening rules are derived as sufficient conditions for the intr insic dissipation inequality to be satisfied in every process. This is quite analogous to the case of infinitesimal deformation, but now the hardening rules take a very specific form which is explained in the p aper.