A general material law of plasticity and its numerical application

FE-codes for numerical simulations of metal forming processes need very general material laws. In this paper constitutive equations are proposed which include real-time and endochronic effects as well as kinematical hardening and a variable Hill-anisotropy. The law presented here is denoted in terms of strain spaces. The objective rates occurring in the evolutional rules of internal parameters include the concept of plastic spin to avoid physically meaningless oscillations of stresses in case of shear processes. Additionally an integrational scheme is presented which works very robustly and highly precisely even if very large strain differences occur within one time-step of the integration.