基于综合裕度的环肋圆柱壳多目标优化研究

Study of Multi-objective Optimization of Ring Stiffened Cylindrical Shell Based on Weighted-sum Margin

圆柱壳的肋骨应力裕度较小而其他应力和临界载荷的裕度较大是设计中常见的问题。文章提出了综合裕度的概念,建立基于综合裕度的环肋圆柱壳多目标优化模型。目标函数为综合应力裕度、综合临界载荷裕度和质量。采用NSGA-Ⅱ算法进行优化求解,Pareto解各属性裕度的统计结果显示肋骨应力裕度较小;分析了肋骨许用应力值对优化结果的影响,数据结果表明适当放宽肋骨的许用应力能解决肋骨裕度较小的问题。

Small margin of ring stress with large margin of other stress and critical load of the cylindrical shell is a common problem in design. The concept of weighted-sum margin is proposed and the multi-objective optimization model of ring stiffened cylindrical shell based on the weighted-sum margin is constructed in this paper. The objective functions are the weighted-sum stress margin, weight and weighted-sum critical load margin,respectively. The NSGA-II method is used to get the Pareto set. The analysis of Pareto set shows that margin of ring stress is small. The effects of the allowable value of ring stress on optimum results are studied. The numerical results suggest that the unevenness between margin of strength and stability can be solved by loosening allowable value of ring stress properly.