剪切载荷下含椭圆形大开口层合板的试验研究

在面内纯剪切载荷作用下, 采用试验与有限元模拟方法研究了结构中心设置椭圆形大开口的正方形复合材料层合板的应力/应变集中现象及屈曲、 后屈曲行为, 通过测试结果对试验件失效模式进行了评估。研究结果表明: 层合板开口附近应力/应变集中程度很高; 大尺寸开口使结构稳定性显著降低, 且开口层合板具有较好的后屈曲承载能力; 由于弯曲产生高水平的层间应力, 导致局部分层损伤并伴有基纤剪切破坏; 随着横向挠度的增加, 各应力集中区域的纤维发生拉伸断裂, 导致整体结构瞬间发生脆性失效。有限元模拟结果与试验结果符合较好。

Experimental study on composite laminate with a large elliptical cutout under shear load

Experiments and finite-element-method(FEM) analysis have been conducted to investigate the effect of a large size elliptical cutout on the stress/strain concentration and buckling, post-buckling behaviour of a square composite laminate under in-plane shear load. It is observed that the stress/strain concentration near the vicinity of cutout is considerable and the stability of the laminate declines remarkably due to the large cutout. The post-buckling loading capacity of laminate structure with a cutout is specific high. The failure modes of the test panel evaluated by experiments show that the high inter-laminar stress induced by the bending of laminate leads to the local damage of delamination companied by the fibre matrix shear-out. And with the structure’s horizontal deflection increasing, the fibre in the stress/strain concentration area is stretched to fracture resulting in the whole laminate collapsed instantaneously. The FEM analysis results agree well with the experimental results.