R-curve behaviour in weak interface-toughened SiC-C laminates by discrete element modelling

Tough ceramics can be made by introducing weak interfaces which deflect a growing crack. A simple discrete element model was employed to study crack growth in SiC-C laminate with graphite as weak interfaces. By modelling the three-point-bending test of the notched laminate, de-bonding, de-lamination and crack deflection were observed dynamically. The fracture features of the laminate as like “graceful failure” and R-curve behaviour were replicated both qualitatively and quantitatively. It has been revealed that the strength of the weak interface should be in a certain range to assure the appearance of the toughening effect. A minimum presence of the weak interface is required to increase the strength of the laminate. The employed model is explicit and simple, it can be used to reproduce the dynamic process of crack propagation in ceramic laminates and guide the design of the laminate's structure in the future.