Analysis of the LEFM concept for interfacial cracks application to coating buckling delamination in terms of substrate elastic characteristics

In this paper the buckling delamination of a coating on a flat substrate in form of a straightsided blister with special attention paid to the influence of elastic characteristics of the substrate is considered. Conditions for the buckling initiation are analyzed as well as the energy release rate and mode mixity of the interface crack as functions of the difference in elastic characteristics of the coating and the substrate. The problem is discussed from the aspect of application of the linear elastic fracture mechanics (LEFM) concept for the interfacial crack. The real angle function ! of the Dundurs parameters and and the ratio of thicknesses of the two layers are used for determination of the energy release rate and the load phase angle. Both the energy release rate along the sides of the blister and the average energy release rate at the front of the blister were calculated. The results thus obtained justify the application of the LEFM concept for interfacial cracks to the considered problem.