Modelling the thermoplastic material behaviour of a tailored formed joining zone on a microscopic length scale with focus on the steel component

Abstract

Since Tailored Forming is a complex process and the joining zone of the hybrid solid component is a possible weakness, our goal is to simulate the thermomechanical material behaviour of the joining zone during the Tailored Forming process. Investigations on the steel component of the joining zone show a polycrystalline microstructure with the two constituents pearlite and ferrite. In this work, the pearlitic phase is considered to be purely thermoelastic whereas the material model for the ferritic phase represents thermoplastic material behaviour. Besides reasons for the choice of the mentioned material models, we present the thermoplastic material model developed by Zeller et al. [1]. Based on the experimental observation that the persistent deformation is a result of slip of dislocations, state variables are defined to formulate a necessary shear stress to move dislocations as well as temperature and deformation dependent evolution equations for the introduced state variables.