Three-stage model of an elastoplastic cracked body

We propose a three-stage model of an elastoplastic cracked body, which takes into account the evolution of stresses in the prefracture zone according to the complete tensile stress-strain diagram of the investigated material. The zone of loosening corresponding to the last (descending) part of the tensile stress-strain diagram lies in the immediate vicinity of the crack tip. The zone of plastic deformation of the material is located after the zone of loosening. These zones are simulated by separate rectilinear stress-strain diagrams taking into account the effect of linear hardening of the material. Within the framework of the proposed model, we formulate a deformational fracture criterion and determine the characteristics of crack resistance of D16T steel.