Penetration direction of a crack terminating at a bi-material interface obliquely

Crack penetration direction at a bi-material planar interface has been investigated numerically as a function of primary crack obliquity. Crack penetration angle prefers to follow the normal direction to the interface unless the crack obliquity is overly high. The retarded offset of the penetration angle from the direction normal to the interface is more apparent as Dunders' parameter α decreases to -0.9, whereas the increase in α toward 0.9 fosters the offset of the penetration angle from the direction normal to the interface. This behavior has been well explained qualitatively in terms of the phase angle of the primary crack.