考虑层间应力的厚复合材料结构多级优化设计方法

充分发挥复合材料的利用率,降低结构重量,厚复合材料结构优化设计是非常重要的。然而优化设计空间复杂,层间应力问题突出,离散设计变量等问题使得厚复合材料结构的优化变得十分困难。针对由铺层相同的子层板叠成的厚复合材料层合板结构的复杂优化问题,本文提出一种多级优化设计方法。第一级优化采用基于径向基神经网络代理模型的优化设计方法,设计变量为子层内层数及铺层比例;第二级优化分为两个层次进行,系统层以结构重量最轻为目标,设计变量为子层数,子系统层采用遗传算法优化铺层顺序,以层间应力因子最小为目标。结合算例,通过Matlab编写遗传算法,并应用Isight集成Matlab来实现该优化设计方法。结果表明:本文提出的多级优化设计方法是有效的,能够很好地实现具有周期性铺层方式的厚复合材料层合板结构的优化设计。

Multi-step Optimization Method of the Thick Composite Laminate Structures Considering Inter-laminar Stresses

Aiming at the optimum design of thick composite structure which is formed by repeating sub-laminates,?a multi-step optimization method is proposed in this paper. This method is composed of two steps. The first-step optimization design is conducted using the approximate model which is based on radial basis function neural network. The design variables include the number of plies in the sub-laminate and ply volume proportion. The second-step optimization is divided into two levels. The design variables of the system level are the number of sub-laminates, and the objective is to minimize the structural mass. The sub-system level is the optimization of laminate stacking sequence using genetic algorithm, and the objective is to minimize the inter-laminar stress factor. Matlab is adopted to program the genetic algorithm, and then integrated with Isight to carry out the whole optimization process. The case study shows that the multi-step optimization design method proposed in this paper is effective. The optimization method provides the idea for the initial design of thick composite structure and is of significant practical value in engineering.