Quasi-Static Propagation of Subinterfacial Cracks

The problem of quasi-static crack propagation in a three-point bend specimen containing an initial crack that is parallel to and offset from a bimaterial interface is considered. An approximate dislocation-based fracture model is used to identify conditions under which such cracks are attracted to or repelled by the interface. Possible configurations (material/geometry) where such subinterfacial cracks experience pure mode I conditions are determined. Experimental results are presented showing quasi-static crack propagation of subinterfacial cracks for three regimes: (attractive) into the interface; (repulsive) away from the interface; as well as (equilibrium) parallel to the interface. [S0021-8936(00)01903-6]