Limit States of Adhesive Layers under Combined Loading

The state of pre-fracture of a thin adhesive layer of finite thickness in the vicinity of a crack-like defect is considered. It is proposed to take into account the hydrostatic pressure, which forms the volume deformation energy, in order to find the critical state. The critical value of the J-integral for the I+II loading mode is assumed to be dependent on the product of the volume strain energy and the layer thickness at the end face of the adhesive. The limiting value of the product of the volume energy and the layer thickness under loading in mode I, as well as the critical values of the J-integral for loading modes I and II, determine the value of the loosening parameter of a particular adhesive in the proposed failure criterion.