ON THE BEHAVIOUR OF INTERFACE CRACKS.

A large number of elasticity solutions for interface cracks that have become embedded in the literature over the years are contradictory because they predict interpenetration of material. The contradictions can be avoided by recognizing that crack problems inherently lead to unilateral constraints and require that certain inequalities be incorporated in the formulation. This article sets out the appropriate conditions for the formulation, shows the character of the elastic fields at the various transitions in the boundary conditions, and discusses the anticipated behavior of interface cracks as it emerges from recent solutions that are free of contradictions.