考虑劈裂对应力集中缓解作用的纤维增强复合材料损伤破坏分析

外载荷作用下含缺口纤维增强复合材料层合板在缺口边缘存在很高的应力集中，在载荷水平较低时，缺口边缘纤维间基体受剪切作用会发生沿纤维方向的纵向劈裂，该纵向劈裂会降低缺口处的应力集中并提高层合板的承载能力。为准确模拟纵向劈裂对缺口边缘应力集中的缓解作用，利用扩展有限元方法模拟劈裂建立了复合材料层合板渐进性损伤破坏分析的仿真模型，模型选用Hashin破坏准则对复合材料层合板的失效进行预测，分别研究了铺层顺序和缺口形状对复合材料层合板抗拉强度的影响，并与现有文献中的实验结果进行了对比，模拟结果表明破坏模式和破坏强度均与实验结果相吻合，验证了本文渐进性损伤破坏分析仿真模型的有效性。

Damage and failure analysis of fiber-reinforced composites considering the alleviation effect of splitting on stress concentration

Serious stress concentration occurs at the notch edge of fiber-reinforced composite laminates under external load. At a low load level, longitudinal splitting along the fiber direction will develop in the matrix between fibers at the notch edge under shear deformation. The longitudinal splitting will relieve the stress concentration at the notch edge and improve the load-carrying capacity of the composite laminates. In order to accurately simulate the alleviation effect of longitudinal splitting on the stress concentration at the notch edge, a simulation model for the progressive damage and failure analysis of composite laminates is established in this study by using the extended finite element method (XFEM) to simulate the splitting. Based on the Hashin damage criterion, the model is used to predict the failure of composite laminates and study the effects of notch shape and stacking sequence on their tensile strengths. The simulation results are compared with the experimental results in existing literature and it shows that the failure strength and failure mode are consistent with the experimental results, which verifies the effectiveness of the numerical simulation method for progressive failure analysis of composites.