On the simulation of plastic forming under consideration of thermal effects

A new model of finite strain thermo-viscoplasticity is constructed. The model takes a combined nonlinear isotropic-kinematic hardening into account in a thermodynamically consistent manner. The yield stress and some of the hardening parameters are temperature dependent. The equation of the heat conduction is obtained directly using the energy balance. In particular, the thermoelastic effect and the mechanical dissipation are obtained in a natural way. Unlike the classical Taylor-Quinney rule, which yields in the case of a strong kinematic hardening inconsistent simulation results, the developed model enables physically reasonable computations. In order to capture the energy storage associated with the inelastic deformation more precisely, an additional component of the free energy - the so-called detached free energy - is introduced. Using this constitutive assumption, a better fitting of the model prediction concerning the real temperature evolution can be achieved.