Crack deflection at an interface between dissimilar elastic materials

A crack impinging an interface joining two dissimilar materials may arrest or may advance by either penetrating the interface or deflecting into the interface. The competition between deflection and penetration is examined in this paper when the materials on either side of the interface are elastic and isotropic. The energy release rate for the deflected crack is compared with the maximum energy release rate for a penetrating crack. The results can be used to determine the range of interface toughness relative to bulk material toughness which ensures that cracks will be deflected into the interface.