Modelling shear behaviors of 2D C/SiC z-pinned joint prepared by chemical vapor infiltration

Progressive failure model is developed to investigate shear behaviors of 2D C/SiC z-pinned joint prepared by chemical vapor infiltration (CVI). It includes progressive failure model of 2D C/SiC composites and cohesive model of faying plane, in order to describe joint nonlinear shear behaviors and z-pin shear-off failure mode, respectively. All cohesive parameters are directly obtained from mechanical properties of 2D C/SiC composites. Results show that the model can almost reproduce joint shear behaviors and z-pin shear-off failure process. Joint failure results from coupled fiber tensile and fiber–matrix shearing damages at faying plane. The model also successfully demonstrates that joint shear properties can be effectively improved by changing z-pin density and diameter. The relationship between joint properties and mechanical properties of 2D C/SiC composites are subsequently obtained with the model. In this sense, joint shear strength increases with cohesive or in-plane shear strengths of 2D C/SiC composites.