Energy release rate and stress intensity factors of an interfacial crack lying along the wavy interface between a thin film and a substrate is numerically analyzed under a pure tension load and a thermal load of rapid constant temperature rise on the surface of the thin film. The stress intensity factor and energy release rate is obtained by using the finite element method.
The results are as follows ; the ratio of the thin film thickness with respect to the length of the crack has an important effect on the stress intensity factor and energy release rate. Under pure tension load, larger waviness results in smaller energy release rate. On the other hand, under thermal load larger waviness results in larger energy release rate. The energy release rate for the case of a stiffer thin film than a substrate is smaller than that for the case of the same material combinations with the thin film and the substrate materials interchanged.