含表面裂纹的复合材料层压板剩余强度的工程算法

Engineering algorithm of residual strength for cracked composite laminates

表面裂纹可导致复合材料层压板的强度降低,针对一些对裂纹敏感的复合材料关键部件有必要计算裂纹对层压板剩余强度的影响。传统预测层压板剩余强度的方法均与层压板具体铺层方向有关,通过研究具有表面裂纹的碳纤维/环氧树脂层压板的剩余强度特性,提出了一种与铺层方向无关的预测层压板剩余强度的工程算法。首先,利用裂纹几何参数以及层压板相关力学性能参数对剩余强度进行快速估计,再基于内聚力单元建立含表面裂纹的复合材料层压板的有限元模型,通过对含表面裂纹的层压板的渐进损伤过程进行描述,研究了裂纹深度和长度对剩余强度的影响,验证了工程算法的合理性。

Surface cracks can cause the strength of the composite laminate to decrease.For some critical composite components sensitive to local surface cracks,it is necessary to calculate the residual strength of cracked laminates.The traditional methods to predict the residual strength of laminates are related to the direction of the layup.In this paper,the residual strength of carbon/epoxy laminates with cracks was investigated,anda residual strength prediction method based on the damage morphology was proposed,which was independent of the layup direction.A series of models with cracks of different length and depth was simulated,using cohesive finite elements as prefabricated cracks in the interface.This paper describes the progressive damage process of laminates with surface cracks,and proposes a universal approach to predict the residual strength of cracked laminates.With the parameters of crack geometry and related mechanical property,the residual strength can be easily estimated.