Crack growth in ceramic laminates with strong interfaces and large compressive residual stresses

Residual compressive stresses developed in layered ceramics may improve the crack resistance of the material during crack growth by reducing the crack driving force at the crack tip. i.e. R-curve behaviour occurs. Elastic contrast of layers often plays an important role by inducing an additional crack driving force term which can promote (anti-shield) or retard (shield) the crack propagation. Since the toughening effect of the residual stress state is often predicted by means of the weight function method, it is matter of interest to find limits for the application of weight function concept in elastically inhomogeneous laminates. Another objective of the paper is to investigate in detail the very process of crack transition across thermo-elastically mismatched layer interfaces. Due to the discontinuity in the elastic properties, finite crack extensions are to be considered instead of infinitesimal one. The concept of Finite Fracture Mechanics (FFM) is applied to tackle this problem.