Z-pin增强树脂基复合材料单搭接连接性能

为提高复合材料单搭接头的连接性能，制备了不同参数的Z-pin增强单搭接头，通过拉伸试验，研究了Z-pin体积分数、直径以及植入角度对单搭接头连接性能的影响规律，分析了Z-pin对单搭接头性能的增强机理。结果表明Z-pin能明显提高复合材料单搭接头的连接性能：植入角度为90°、Z-pin直径为0.5 mm时，在0%~3.0%体积分数范围内，单搭接头强度随着Z-pin体积分数的增加呈线性增加，含3.0% Z-pin的接头剪切强度为16.76 MPa，比无Z-pin的接头强度提高了33.2%；Z-pin体积分数为1.5%、植入角度为90°时，Z-pin直径变化对单搭接头强度影响不大；含Z-pin体积分数为1.5%、直径为0.5 mm时，随着Z-pin植入角度（背离搭接末端）的增加，单搭接头强度先增加后下降，失效模式从Z-pin拔出失效转变为Z-pin剪断失效；在植入角度为40°时，剪切强度最大（21.04 MPa），比无Z-pin的接头剪切强度提高了67.1%。Z-pin植入角度（倾向于搭接末端）对单搭接头强度无影响。

Performance of Polymer Composite Single Lap Joints Reinforced by Z-pin

To enhance the performance of polymer composite single lap joints, the joints reinforced with different configurations of Z-pins are manufactured and tested. The effects of the volume fraction, diameter and implant angles of the Z-pins on the strength of single lap joints are investigated and their reinforcing mechanism is also analyzed. The study finds that the Z-pin can improve the performance of single lap joints significantly: When the Z-pin's diameter is 0.5 mm and the implant angle is 90°, the joint's strength increases linearly with the Z-pin volume fraction from 0% to 3.0%. The maximum strength is 16.76 MPa with a 3.0% Z-pin fraction, which is 33.2% higher than that without Z-pin. It also reveals that the Z-pin's diameter has little influence on the strength of polymer composite single lap joints while the Z-pin fraction is 1.5% and the angle is 90°. The strength and failure model is strongly dominated by the implant angles of the Z-pin (against the joint edge) for a Z-pin fraction of 1.5% with a diameter of 0.5 mm. With the increase of the implant angles, the failure mode of the joint is transformed from Z-pin pulling out to Z-pin shearing. The strength reaches its peak value of 21.04 MPa at 40°, which is 67.1% higher than that without Z-pin. The implant angles of the Z-pin (along the joint edge) have no influence on its strength and failure mode.