Asymptotic stress field of a mode III crack growing along an elastic/elastic power-law creeping bimaterial interface

The asymptotic stress field near the tip of a crack subjected to antiplane shear loading is analysed. The crack is growing quasi-statically along an elastic/elastic power-law creeping bimaterial interface. We find there is a separable solution with the following characteristics: for n < 3, where n is the power-law creeping exponent, the asymptotic stress field is dominated by the elastic strain rates and has an inverse square root singularity, r^-1/2, where r is the distance from the current crack tip. For n > 3, the near-tip stress and strain fields has a singularity of the form r^-1(n-1). The strength of this field is completely specified by the current crack growth rate, besides material properties, and is otherwise independent of the applied load and of the prior crack growth history.