Analysis of Crack Resistance of Interfaces between Materials

Abstract

A model of fracturing of an interface between dissimilar materials in the presence of a section of weakened bonds between materials is considered. Such a section is modeled by a crack, between the faces of which adhesion forces act, depending on the crack opening. The size of the interaction zone of the crack faces (bridged zone) can change during the crack growth and is not small compared to the crack size. To analyze the quasi-static growth of a crack with an bridged zone filled with bonds, a nonlocal fracture criterion is used, taking into account the work on deformation of the bonds in the bridged zone of the crack. The state of limiting equilibrium of the crack tip corresponds to the energy condition of the equality of the rate of deformation energy release at the crack tip and the rate of deformation energy consumption by bonds in the bridged zone of the crack (the first fracture condition). The breaking of bonds at the trailing edge of the bridged zone is determined by the condition of their limiting stretching (the second fracture condition). Proceeding from these two conditions, the modes of subcritical and quasi-static crack growth are considered and two main parameters of fracture are determined, that is, the critical external load and the size of the tip region of the crack in the state of ultimate equilibrium.