Application of Constitutive Law Incorporating Stress Increment Directional Dependence to F. E. M. Analysis : 1st Report, Plane Strain Shear Band Formation

A constitutive law of plastic deformation has been proposed by Goya and Ito, and can incorporate the stress increment directional dependence of plastic strain increment ε^p. The law is developed through the introduction of two transition parameters μ(α) and β(α), which denote the magnitude and the direction angle of the plastic strain increment, respectively, and are defined to be functions of the direction angle of the stress increment. In this report, the law is implemented in an F. E. M. code for deformation analysis. A plane strain tension problem is analyzed for investigation of the effect of these parameters on the occurrence of the shear band. The results show that the clear shear does not appear when the calculation is performed using B_=π/6, which corresponds to the degree of the directional dependence for the corners of the Tresca yield locus