TANGENTIAL PLASTICITY. NUMERICAL MODELS IN GEOMECHANICS. NUMOG III. PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM HELD AT NIAGARA FALLS, CANADA, 8-11 MAY 1989

The description of plastic deformation due to the stress change along the yield or loading surface and the mutual dependency between a stress rate and a plastic strain rate is of importance for the analysis of plastic instability phenomena with a localization/bifurcation. To this aim, various approaches have been proposed in the past. They include, however, fundamental problems, e.g., the violation of the continuity condition and the nonlinearity of equations. In this paper, a reasonable constitutive equation is derived by incorporating into the subloading surface model the plastic strain rate due to the stress rate tangential to the subloading surface.(a) for the covering abstract of this conference see IRRD 824029.