Numerical analysis on special cracking phenomena of residual compressive inter-layers in ceramic laminates

Finite element computations are performed to analyze the phenomena of edge cracking and crack bifurcation in two ceramic laminates composed by tensile thick layers and compressive thin layers. The difference between these two laminates is the thickness of the compressive thin layers. Experimental results performed by one of the authors in previous works show that edge cracks exist in only one laminate, while crack bifurcation occurs in both laminates under bending. To understand the cracking phenomena observed in experiments, the energy release rates are calculated. Numerical results show that the initiation of crack bifurcation can be explained by the near-tip J-integral, provided that micro-cracks exist near the crack tip.