利用有限元软件分析了X-cor夹层结构的剪切强度及失效机理, 提出了失效判据和材料刚度退化规则, 明确了X-cor夹层结构的失效过程和模式; 根据失效判据, 采用有限元模型中发生刚度退化的单元及其分布模拟失效类型及扩展路径, 说明了X-cor夹层结构的剪切失效机理。结果表明: 在剪切载荷下, 树脂区首先失效, 然后是Z-pin拔出面板、Z-pin被剪断及Z-pin屈曲多重失效模式并存; 有限元分析结果与试验数值吻合较好, 说明了失效判据和刚度退化规则选择的有效性。

The finite element software was used to analyze the shear strength and failure mechanism of X-cor sandwich structure. During the shear strength analysis, the failure criterion and materials stiffness degradation rules were proposed, and the failure process and modes of X-cor sandwich structure were also clarified. According to the failure criterion, the elements with stiffness degradation and their distributions in the finite element model were used to simulate the types and propagation path of the failure. And the failure mechanism of X-cor sandwich was explained. The results show that under shear load the resin regions fail first; and then the multiple failure modes of Z-pin pull-out from the face-sheet, Z-pin shear off and Z-pin buckling appeared. The finite element results were consistent well with the values of test result after comparison, which meant that the failure criterion and stiffness degradation rules were effective.