复合材料开孔平板剪切稳定性研究

Study on Shear Stability of Composite Plates with Cutouts

本文对复合材料开孔平板试验件进行剪切载荷下的稳定性分析。对厚度为2mm,铺层为16层的开孔平板进行剪切稳定性试验。采用工程算法对复合材料平板的临界屈曲载荷与剪切屈曲应变进行计算,该方法考虑了铺层与边界条件的影响。通过有限元仿真软件建立剪切平板模型,计算模型的屈曲模态,并将模态作为初始缺陷引入模型,通过有限元弧长法计算复合材料平板模型的非线性屈曲载荷及屈曲应变。对于平板模型,工程算法得到的剪切屈曲载荷、屈曲应变与有限元模型计算的结果基本吻合。对于带孔平板模型,利用有限元弧长法仿真得到剪切载荷作用下的应力分布及非线性屈曲载荷,与试验结果对比较好。通过有限元结果与试验、工程算法结果对比,验证了有限元模型的可靠性。基于验证过的有限元模型进行了参数化研究,评估了不同开孔直径对复合材料平板剪切屈曲稳定性的影响。研究结果表明,开孔会导致结构剪切屈曲载荷显著下降,孔边比为0.3时,为临界屈曲载荷最优的结构模型。开孔直径越大,结构的剪切屈曲载荷越小,孔边应变逐渐增大。

In this paper,the stability analysis of the composite panel with cutout under shear load is carried out.Shear stability test is carried out on a 2 mm thick plate with 16 layers.The buckling load of the shear loaded panel is calculated by analytical method,which considers the influence of layer and boundary conditions.The shear plate model is established by finite element(FE)method,and the buckling model of the model is calculated.The model with cutout is introduced into the model as the initial defect.The nonlinear buckling load and buckling response of the composite plate are calculated by the finite element curvature length algorithm.For the panel without cutout,the shear buckling load and strain obtained from analytical calculations shows a good agreement with FE model.For the panel with cutout,the FE results of stress distribution and nonlinear buckling load agrees the test results.The reliability of the FE model is proved by the experiments by comparing the test results and analytical calculation.A parametric study based on an experimentally proved FE model is carried out to evaluate the cutout effect on the shear buckling stability.The results show that holes can significantly reduce the shear buckling load of the structure.When the hole to edge ratio is 0.3,it is the optimal structural model for critical buckling load.The larger the opening diameter,the smaller the shear buckling load of the structure,and the gradually increasing strain at the hole edge.