Rapid tearing along an interface

A half-space composed of two joined elastic quarter spaces of different material properties is subjected to anti-plane surface tractions parallel to the interface. We investigate the case that the application of the surface tractions instantaneously gives rise to rupture at the surface trace of the interface. A zone of rupture, or delamination, subsequently propagates at a relatively large velocity as a stress-free crack along the interface. Wave motions in the two quarter spaces are analyzed, and the elastodynamic stress intensity factor of the interface stress is computed. An expression is derived for the rate of energy flux into the propagating crack tip.