Modelling of yield point phenomenon in bake-hardening grade steel

Abstract. In this study the yield point phenomenon in Bake-Hardening grade steel is predicted using a physically based thermo-mechanical model. A modified Taylor equation proposed with dislocation density evolution approach. The softening that follows higher incorporated Voce type decaying exponential function. strain rate dependency of plastic hardening also decay function dependent but does not follow same hardening. This was solved by making adding stress term to parameter calculated on tensile experiments. Due behavior material, numerical model mesh size sensitive. Hence, lower order gradient enhanced approach implemented. form an additional assigned locally strained bands gradient. Hill48 criterion used assimilate anisotropy grade. results show good correspondence experimental tests. regularization significantly reduced results.