复合材料层合板临界屈曲载荷分散性

Critical buckling load discrepancy of composite laminates

基于随机场理论,将纤维和基体性能以及纤维体积分数作为随机场变量,利用局部平均法对随机场进行离散。结合MATLAB与ANSYS的PDS模块对复合材料层合板临界屈曲载荷进行Monte-Carlo模拟,分析各类随机场变量、随机场的相关长度、对称性和边界条件对临界屈曲载荷分散性的影响。结果表明:不同随机场变量对层合板屈曲载荷分散系数影响的程度不同,纤维体积分数的影响最大,其次为纤维性能与基体性能;屈曲载荷的分散系数存在尺寸效应,随着板尺寸的增加,屈曲载荷分散系数逐渐减小;减小相关长度可有效地减小屈曲载荷的分散系数;纤维正对称铺设所引起的屈曲载荷分散系数稍大于反对称铺设情况,而两对边固支板的屈曲载荷分散系数一般大于四边简支板的结果。

Based on the random field theory, the random field was discreted by local average method with the material properties of fibers and matrix and the fiber volume fraction as variables. The Monte-Carlo simulation of the critical buckling load discrepancy for composite laminates was performed combining MATLAB and PDS module of ANSYS, and the influences of the discrepancy features of various random field variables, the correlation distance, the symmetry characteristic as well as the boundary condition were analyzed on the discrepancy of the critical buckling load. The results show that various random field variables have different influences on the critical buckling load discrepancy for composite laminates, among which the fiber volume fraction being the strongest factor and fiber and matrix properties being the next. The coefficient of variance（COV） for the critical buckling load has size effect and it reduces individually with the plate size increases. Reducing the correlation length can effectively incline the discrepancy of critical buckling load. The COV for the critical buckling load for symmetric laminates is slightly bigger than that for antisymmetric laminates. The COV for simply-supported laminates is generally less than that for two corresponding sides fixed supported laminates.