Institute of Fundamental Technological Research

The classical J2 plasticity theory is widely used to describe the plastic response of metallic materials. However, this theory does not provide satisfactory predictions for materials which exhibit pressure-sensitive yielding or plastic dilatancy. Another difficulty is the so-called strength differential effect (SD), leading to the asymmetry of the elaasstic range. The Burzyński yield condition, proposed in 1928, can be used to overcome some of these problems. In this paper an implicit integration of the elasto-plastic constitutive equations for the paraboloid case of Burzyński yield condition is frmulated. Also, the tangent operator consistent with the integration algorithm was developed and is presented. The proposed model was implemented in a commercial FE code and different kinds of tests reported in the literature were simulated. The comparison between the numerical and experimental results shows that the plasticity theory with the paraboloid case of Burzyński's yield condition describes adequately the strength diffrential effect, which is present in many kinds of materials significant for recent applications.

metal matrix, mechanical, plastic behaviour, Burzyński paraboloid yield condition, strength differential effect