Z-pin增强复合材料开孔层合板压缩性能

针对复合材料开孔层合板孔边应力集中而导致承载能力降低现象,采用Z-pin增强技术提高性能。重点了研究开孔层合板的压缩性能,制备了不同Z-pin植入体积分数的开孔层合板试样并进行了压缩试验,在试验基础上,应用有限元分析方法对Z-pin增强开孔层合板进行建模分析,基于渐进损伤分析法和内聚单元法模拟了复合材料基体以及Z-pin的增强效果。试验结果表明:Z-pin的植入可以显著提高开孔层合板的抗压性能,且随着Z-pin植入体积分数的提高,压缩性能不断上升,压缩强度最高可以提高23.06%;只有沿载荷方向,位于开孔两侧的Z-pin可以提高结构的承载能力;在Z-pin桥联力的作用下,降低了损伤的扩展速度,但并没有改变层合板的最终失效模式。模拟结果表明:压缩损伤从孔边向两侧扩展,位于层合板中心的铺层最先出现损伤,其中第6层与第10层的增强单元最先发生破坏。模拟计算结果与试验结果得到了较好的吻合,该有限元模型对于Z-pin增强复合材料开孔层合板的适用性得到了验证。 

Compression performance of open-hole composite laminates reinforced by Z-pin

Z-pin reinforced technique was used to improve the performance of open-hole composite laminates, in view of load capacity reduction because of the stress concentration at the edge of the hole. The influence of the Z-pin insertion percentage on the compression performance of open-hole composite laminates was analyzed by testing the compression properties of laminates with different Z-pin inserted percentages, finite element models of the classical cohesive elements and open-hole composite laminates were established to analyze the influencing mechanism. Results showed that the reinforcing pins increased the compressive strength by 23.06% maximally. Only along the compressive loading direction, the Z-pin located on both sides of the hole can reduce the damage expansion speed by bridging force, but the ultimate failure mode of laminates was not changed. Numerical results showed that the compression damage extended from the edge of the hole to both sides, and the lamination in the center of the laminate was the first to be damaged, among which the cohesive elements in the 6th and 10th layers were the first to be damaged. The simulation results were in good agreement with the test results.