Аннотация:The behavior of the structural microdefects in damaged media changes depending on the loading conditions. Therefore, materials with microcracks, inclusions or pores are characterized by the dependence of the deformation and strength properties on the stress state type. This complicates the description of the deformation process. The analysis of the experimental data shows the absence of a unified diagram for the dependence of the intensity of the tangential stresses on the strain intensity, the interdependence between the shear and volume strains, the appearance of irreversible volume strains, and a number of other specific features. Such properties are characteristic, for example, of engineering graphite, concrete, cast iron, some ceramic and composite materials, and rocks [1-7].
In the present paper, we investigate the influence of these specific features of the deformation on the character of asymptotic solutions near macrocracks in a hardening material. The case of plane stress state is considered. An approximation for material functions is suggested. This approximation allows one to describe the experimental strain diagrams with reasonable degree of accuracy. For specific material functions, the distributions of stresses, strains, and displacements near the crack tip are obtained. These distributions are compared with those following from the solution of a similar problem for a plastically incompressible medium. The conditions of the crack initiation are determined in terms of the invariant integral.