CONSTITUTIVE-EQUATIONS FOR PLANAR DEFORMATIONS OF RIGID-PLASTIC MATERIALS

CONSTITUTIVE equations governing the plane deformation and flow of an isotropic rigid-plastic material obeying a Mohr-Coulomb or other type of yield condition are presented. The equation is a quasi-linear relationship between the strain-rate, Cauchy stress and the co-rotational rate of the Cauchy stress. It synthesises two previously separate types of models, namely those models that admit a plastic potential and the double-shearing models. The proposed model is determined by the choice of yield criterion, plastic potential and by the condition that the stress and velocity characteristic curves in plane deformation are coincident. Pressure dependence upon yield and dilatancy are incorporated into the theory in the classical way via the angles of internal friction and dilatancy.