压剪联合载荷作用下复合材料壁板屈曲及后屈曲性能计算与优化方法研究

复合材料壁板被广泛用于航空航天结构,在外部复杂工况下壁板通常会受到面内压剪载荷的联合作用,其屈曲及后屈曲响应直接影响此类结构的极限承载能力。为此,基于改进的Koiter摄动理论,提出一种能够快速精确地开展复合材料壁板非线性屈曲分析的摄动有限元降阶方法,然后计算获得壁板的屈曲/后屈曲性能指标,即非线性屈曲载荷、后屈曲承载刚度以及承载刚度残余系数,最后将摄动降阶方法嵌套到复合材料铺层优化的分析流程中,获得压剪联合载荷下各种屈曲/后屈曲性能指标的最优铺层信息。数值算例验证了所提出方法的高效性和有效性。

A Novel Method for Calculation and Optimization of Buckling and Post-Buckling Performance of Composite Panels under Combined Compression and Shear Loads

Composite panels are widely used in aerospace structures. Under complex external conditions, the panels are usually subjected to both in-plane compression and shear loads, and their buckling and post buckling responses directly affect the ultimate bearing capacity of such structures. Therefore, based on the improved Koiter perturbation theory, this work proposes a perturbation finite element reduction method, which can quickly and accurately conducts the nonlinear buckling analysis of composite panels. Then the buckling/post-buckling performance indexes of composite panels are calculated, i.e. nonlinear buckling load, post-buckling bearing stiffness and residual stiffness coefficient. Finally, the perturbation reduction method is implemented into the lamination optimization process of composite panel, and the optimal ply informations for various buckling / post-buckling performance indexes of composite panel under combined compression and shear loads are obtained. Numerical examples show the efficiency and effectiveness of the proposed method.