Instability of Plastic Strain and Fracture. Strain Diagram for Inhomogeneous Media

A strain diagram for a locally inhomogeneous medium (a medium with a porous structure or a system with noncut particles) is constructed on the basis of the Cosserat nonlinear–pseudocontinuum model. A modified criterion of geometrical softening that allows one to establish the dependence of the moment of stability loss on the statistical characteristics of the medium is considered.