ON THE MACROSCOPIC DESCRIPTION OF STORED ENERGY AND SELF-HEATING DURING PLASTIC-DEFORMATION

In order to describe the complex cyclic hardening and softening proper ties of austenitic steels, we developed a simple phenomenological plas ticity model during previous work. Now, we embed the model in a thermo mechanical framework such that the second law in terms of the Clausius -Duhem inequality is fulfilled. Since the thermomechanical generalisat ion of the model is a rather formal and in some sense an arbitrary pro cedure, we check the implications of the generalised phenomenological model in context of two thermomechanical investigations. First, we stu dy the fraction of the plastic work, which is not dissipated as heat a nd consequently stored in the material. Second, based on some simplify ing assumptions, we present a semi-analytical solution of the thermome chanical problem of a cylindrical rod heated by plastic dissipation un der uniaxial tension-compression loading. In both cases, the model res ponse is in accordance with experimental observations. (C) 1998 Elsevi er Science Ltd. All rights reserved.