基于等效模型的帽型复合材料加筋壁板优化设计

Optimization of the Composite Hat-stiffened Panel Based on Equivalent Model

本工作提出了一种优化复合材料帽型加筋壁板稳定性的有效方法,该方法是基于在PATRAN软件中用单层板来模拟层合板的力学性能的想法。其中用层合板建的加筋板模型称为详细模型,改用单层板建的称为等效模型。对于航空结构中常见的帽型加筋壁板,本工作采用反映实际壁板形状的高精度有限元模型,分别建立了详细模型和等效模型。比较得出两种模型的一阶线性失稳因子和失稳应变基本一致,从而验证了将等效模型用于帽型加筋壁板结构稳定性分析的可行性。为了便于验证该优化方法的有效性,本工作只考虑加筋板的筋条厚度一致的情况。传统方法在优化蒙皮和筋条厚度时需要优化层合板的每个单层的铺层厚度和铺层顺序,本文提出的优化方法只需要解决单层板的厚度优化问题,相比本方法大大减少了设计变量。本工作用此方法优化得到了两个参数不同的复合材料帽型加筋板的最优屈曲性能,发现只需要2～4次迭代优化就可以收敛,收敛速度很快。

An efficient strategy for the stability optimization of composite hat-stiffened panels is presented.The strategy is based on the idea of the substitution of equivalent orthotropic plates for laminated plates.The stiffened panels made up of laminated plates are named detailed models,and the ones made up of equivalent orthotropic plates are called equivalent models.For common hat-stiffened panels,detailed models and equivalent models are built by adopting high accuracy models that describe stiffened panels' real shapes.By comparison their 1st order linear stability coefficients and buckling strains are in accordance with each other.Therefore it proves that the application of equivalent laminates to hat-stiffened panels' buckling analysis can satisfy the engineering requirements in accuracy.To investigate the feasibility of the method,we only consider the conditon that the whole stiffener shares the only thickness.In particular,it's seen that there are only two design variables involved in this method,that is,skin thickness and the stiffener thickness.Hence,the method has fewer variables than other methods,which treat every ply as design variable.In this passage two design examples are presented to evaluate the optimization strategy.Typically,it needs only two to four steps to complete the whole strategy.