Enhancement of fracture toughness due to energy screening effectin the early stages of non-elastic failure

A triaxiality‐dependent cohesive zone model for a stationary and a quasistatic crack is proposed. The model is rooted in the mesomechanical approach to Fracture Mechanics and is inspired by the quantum law concerning emission of light, which was postulated by Max Planck at the end of the 19th century. The model provides an extension of the early concepts of Barenblatt, Dugdale and the Bilby–Cotrell–Swinden team. It also incorporates the experimental observations of the pre‐fracture states due to Panin and his school in Tomsk. Relations between micro‐ and macroparameters that characterize the deformation and fracture processes in dissipative media are described in detail. The analysis suggests that the ratio of the ‘true’ work of fracture to the total energy dissipated during the course of the irreversible deformation contained within the end zone can be used as a measure of material resistance to a quasistatically propagating fracture.