Evaluation for interfacial fracture of fiber-reinforced pyrocarbon matrix composites by using a zero-thickness cohesive approach

An eight-node zero-thickness element is developed to numerically model the interfacial fracture behaviors of carbon fibers reinforced pyrocarbon (C/C) composites. The constitutive parameters of the developed element are characterised on the basis of the DCB test and three-point ENF test with a novel data reduction approach. A bilinear mixed-mode constitutive criterion is adopted to define the damage initiation and evolution of the interface and the viscous regularization strategy is used to deal with the convergence difficulty in the implicit FE solver. The effects of the interfacial stiffness, the element length and the viscous coefficient on the interfacial fracture behaviors of C/C composites are explored. In addition, a set of angle-ply laminate DCB models of C/C composites are simulated and compared with the experimental tests to validate the effectiveness of the developed cohesive element for modelling the interfacial fracture behaviors of C/C composites. The results show that the proposed interface element with the determined constitutive parameters in this paper can accurately predict the interfacial fracture behaviors of C/C composites.