Effect of Half Thickness Z–pin Implantation on Flexural Properties of Laminates
YAN Bin 1 , CHEN Hanyuan 1 , ZHOU Ju 2 , DAI Yue 3 , LIU Weiwei 1
1. Northwestern Polytechnical University, Xi’an 710072, China;
2. AECC Guiyang Engine Design and Research Institute , Guiyang 550081, China;
3. Xi’an University of Technology, Xi’an 710048, China
Abstract:The effects of material, diameter and twisting state of Z–pin on the bending properties of Z–pin reinforced composite laminates were studied by three-point bending test. The results show that the flexural strength, flexural modulus and flexural strain energy of the reinforced laminates with Z–pin half thickness implantation process are significantly improved compared with the control group. The material, diameter and twisting state of Z–pin have little effect on the flexural strength, modulus and strain energy of the specimens. The reason is that the potential delamination defects at the interface X and Y of the reinforcement group expand seriously, and the delamination damage dominates the failure of the specimen in the bending process. However, the Z–pin diameter has an important influence on the failure mode of laminates. The results show that the delamination crack propagation of small diameter Z–pin reinforced specimens is serious, but the number of initiation cracks is small. The damage of specimens is mostly controlled by a single crack. The crack growth of large-diameter Z–pin reinforced specimens is relatively common, but the number of initiation cracks is more, and the specimens are mostly multi crack damaged.