温度和圆孔缺陷对层合板线性屈曲特性的影响分析

THE INFLUENCE ANALYSIS OF TEMPERATURE AND CIRCULAR-HOLE DEFECT ON THE LINEAR BUCKLING OF LAMINATED PLATE

随着应用环境趋于复杂,层合板经常会处于不同的温度环境以及经常需要开圆孔进行机械连接,且厚度方向尺寸较小,受压缩时容易发生屈曲现象,因此,研究不同温度和圆孔缺陷对层合板屈曲特性的影响具有重要的意义。首先对欧拉梁理论进行简单回顾,推导出梁在两端铰接受压状态时的平衡载荷和挠曲线的解析解。进一步用有限元方法对各向同性板屈曲问题进行研究,将屈曲载荷和屈曲模态与基于欧拉梁理论的解析解进行对照,确定合适的网格密度,验证模型的正确性。然后对含不同圆孔尺寸的准各向同性层合板在不同温度下进行屈曲特性分析,分别得到前五阶的屈曲载荷和屈曲模态。最后研究了不同圆孔尺寸下,圆孔深度对层合板屈曲特性的影响。结果表明:随着温度的升高,含相同圆孔尺寸的层合板的屈曲载荷线性下降;同一温度下,随着圆孔尺寸的增大,屈曲载荷下降越来越快;同一圆孔尺寸下,随着圆孔深度的增加,屈曲载荷下降速度先减小后增大,呈现出对称性。

With the application environment of laminated plates becoming more and more complex,they are often in different temperature environment and often need to drill a circular-hole for mechanical connection,and the size of thickness direction is small,so they are prone to buckling when compressed.Therefore,it is of great significance to study the effects of different temperatures and circular-hole defects on the buckling characteristics of laminated plates.Firstly,the theory of Euler beam is reviewed,and the analytical solutions of the equilibrium load and deflection curve of the beam under the condition of hinged compression at both ends are derived.Furthermore,the finite element method is used to study the buckling problem of isotropic plates.The buckling load and buckling mode are compared with the analytical solution based on the Euler beam theory to determine the appropriate mesh density and verify the correctness of the model.Then,the buckling characteristics of quasi-isotropic laminated plates with different circular-hole sizes are analyzed at different temperature levels,and the first five buckling loads and modes are obtained respectively.Finally,the effect of the depth of the circular-hole on the buckling behavior of the laminated plate is studied.The results show that with the increment of temperature,the buckling load of laminated plates with the same hole size decreases linearly.With the increment of the circular-hole size at the same temperature,the buckling load decreases faster and faster;with the increment of the hole depth at the same circular-hole size,the buckling load decreases firstly and then increases,showing symmetry.