Study and validation of a variational theory of thermo-mechanical coupling in finite visco-plasticity

We present an experimental validation of the variational theory of thermo-mechanical coupling of Yang et al. (2006) in the case of finite thermo-visco-plasticity. The variational theory results in precise predictions of the rate of heating due to dissipation and does not require an a priori definition or model of a fraction of plastic work converted to heat. We show that the predicted heat-to-plastic work ratios are in good agreement with experimental observations for 2024-T3 aluminum, α-titanium and pure polycrystalline tantalum, including their evolution with strain and their dependence on strain-rate. We also critically compare the variational theory to other theories and models in the literature.