where εT and εp are total and plast

where εT and εp are total and plastic strain respectively. Eq. (5) describes the visco-plastic material flow by power law. H is internal stress due to isotropic hardening, and k is the initial yield stress. Eq. (6) is based on Hooke's law. σ is
fl ow stress, and E is the Young's modulus of the material. The material hardening (Eq. (7)) H is calculated according to the accumulation of dislocation