复合材料层合板基于遗传算法的可靠性优化设计

采用遗传算法对复合材料层合板的可靠性优化问题进行了分析。本文研究的算例中 ,在层合结构总厚度一定的情况下 ,以复合材料层合板的系统可靠性指标最大为目标函数 ,对复合材料的纤维方向角或相对厚度进行了优化设计。可靠性分析中 ,采用一次二阶矩法 (FORM)和Tsai Wu准则分析层合板结构的失效概率。算例阐明了遗传算法应用于层合板结构可靠性优化设计的有效性。

Probabilistic Optimum Design of Laminated Plates Based on Genetic Algorithms

The genetic algorithm (GA) is applied to the reliability-based optimum design of laminated composites. The first order reliability method (FORM) is used to estimate the reliability of each ply, and system reliability is computed under both the first-ply failure (FPF) and the last-ply failure (LPF) assumptions. Numerical examples are worked out to show the availability of GA in the optimum design of laminates. In the first example, a laminated plate with initial imperfection subjected to in-plane compressive loading is considered. The objective is the maximum of reliability index and the design variable is ply angle. Two optimum solutions based on FPF and LPF are obtained and compared. Since there are high correlations between the ply-level failure events, the two solutions are very close. In the second example, a series of solutions for different stacking structures are obtained, and the influence of relative ply-group thickness is discussed. These two examples illustrate the simple flow, high computing efficiency and fast convergence of GA.