基于弯曲刚度最大分层临界载荷的层压板局部屈曲预测

提出了一种预测含特定分层损伤层压板发生局部屈曲时整体应变的方法。认为含分层子板的局部屈曲载荷由其弯曲刚度最大的分层决定, 因而含有相同最大弯曲刚度分层的不同子板具有相同的屈曲载荷。在已知弯曲刚度最大分层的屈曲载荷的情况下, 根据层压板的轴向刚度公式, 计算出发生局部屈曲时弯曲刚度最大的分层与完好的基板分别承受的载荷, 即得到总载荷, 进而得到层压板的整体应变。用ABAQUS有限元分析软件建立含分层损伤的层压板模型, 使用准静态加载进行了多种分层深度和分层位置下的局部屈曲仿真, 所得局部屈曲载荷符合上述推论。用所提方法预测发生局部屈曲时的整体应变, 结果与有限元结果吻合较好, 此方法可用于建立分层参数识别的参照样本库。

Local buckling prediction for laminate with delamination based on critical buckling load of the sub-laminate with the maximum flexural stiffness

A method was proposed for the global strain prediction of the composite laminate with special delaminations when the local buckling occurs. It was presented that the critical force of delamination buckling is determined by the maximum flexural stiffness of the sub-laminates in the delaminated region, so if two delaminations of same size have the same maximum sub-laminate flexural stiffness, their critical buckling force must be equal to each other. With the critical buckling force of a certain sub-laminate known, the loads on the debonded layer and intact layers were calculated using their axial stiffness. With the total load the global strain of the laminate was obtained when the local buckling occurs. Then, the three dimension finite element (FE) models of composite laminate with delamination of different area, depth and location were developed with ABAQUS, which are employed to simulate local buckling under quasi-static loading. The obtained delamination buckling loads compliance with above assumption. The proposed method was used to prediction global strain when the delamination buckling occurs, which agrees with those of FE well. Hence this method can be used to set up the samples for delamination depth detection.