Two Plasticity Models Considering Micromechanisms of Observed Phenomena

Abstract

The damage accumulation of many plastically deformable metals, alloys and ceramics under complex thermomechanical loading depends essentially on plasticity micromechanisms. Therefore, for fracture simulation in these conditions it is important to have adequate notions of the preceeding plastic deformation process. The attempts to model some plasticity effects connected with complex loading, transformation plasticity as a rule describe experimental results not quite accurately. In the present paper two plasticity models are proposed and, in order to formulate them, corresponding physical mechanisms on the crystal lattice scale were investigated. The first model is intended to describe the additional hardening effect under nonproportional cyclic loading, the second is to describe transformation plasticity in ceramics. Since the physical mechanisms of both phenomena take place in grain scale, the corresponding models use orientation and statistic averaging.