ADIABATIC HEAT EVALUATION FOR DYNAMIC PLASTIC LOCALIZATION

In most cases, adiabatic plastic heating is evaluated using the inelastic heat fraction coefficient, also known as Taylor-Quinney coefficient, which is usually assumed to be constant. From the thermodynamic viewpoint, this method consists in neglecting (or including some part of) various thermomechanical couplings in the heat equation. Nevertheless this co-arse method can lead to over-estimation of the temperature rise. In this paper, adiabatic shear banding incipience is considered in the context of thermal instability. It is shown that the accuracy in the prediction of favourable conditions for the onset of this plastic localization is strongly dependent on the technique retained for evaluating the plasticity indu-ced heating. This paper aims at showing the influence of various levels of simplification of the thermal equation on the critical conditions at localization onset, the latter being obtained from a criterion based on the linear perturbation method. Key words: adiabatic shear banding, inelastic heat fraction, non-linear mechanics, viscoplasticity 1