Quasi-static propagation of subinterfacial cracks

The problem of quasi-static crack propagation in a three-point bend specime n containing an initial crack that is parallel to and offset from a bimater ial interface is considered. An approximate dislocation-based fracture mode l is used to identify conditions under which such cracks are attracted to o r repelled by the interface. Possible configurations (material/geometry) wh ere such subinterfacial cracks experience pure mode I conditions are determ ined. Experimental results are presented showing quasi-static crack propaga tion of subinterfacial cracks for three regimes: (attractive) into the inte rface; (repulsive) away from the interface; as well as (equilibrium) parall el to the interface.