Prediction of model Ⅰ interlaminar fracture performance for Z-pins reinforced ceramic matrix composites

Based on the experimental results and toughening mechanism of model Ⅰ interlaminar fracture toughness for Z-pins reinforced ceramic matrix composites, a simple pullout model of Z-pins was proposed. The inconsistency of pullout displacement in the scale of Z-pins diameter was considered carefully, prediction model of model Ⅰ interlaminar fracture performance for Z-pins reinforced ceramic matrix composites was obtained by means of the simple double cantilever beam (DCB) theory, and the predicted results were in good agreement with the experiments. Using this analysis as a foundation, the effect on crack tips energy release rate with different Z-pins diameters and crack lengths was studied, and then compared with the method of spring element. Results show that with the increase of diameters, the differences of energy release rate at crack tip gradually increase by two methods, but the difference is relatively small when crack tip is close to Z-pins; however, with the increase of crack lengths, there is a big difference in the two methods energy release rate at crack tip, the inconsistency of pullout displacement in the scale of Z-pins diameter cant be ignored.