基于等稳定要求网壳结构截面优化设计

单层网壳结构是缺陷敏感结构，为降低结构稳定承载力对缺陷的敏感性，提出以稳定承载力随缺陷波动最小（等稳定）为目标函数的单层球面网壳结构截面优化设计方法，即将网壳结构杆件按照缺陷敏感区域进行分组，采用序列两级算法对该分组下的网壳结构模型进行截面优化设计，考虑结构强度、刚度、双重非线性整体稳定等约束条件和随机出现的初始几何缺陷。结果表明，相比于未经截面优化设计的网壳结构，优化得到的新网壳结构在随机给定的28种满足正态分布的初始几何缺陷下，其稳定承载力的均值较大、均方差较小（稳定承载力波动较小），有效提高了网壳结构稳定承载力，降低了网壳结构稳定承载力对初始几何缺陷的敏感性，同时耗钢量略省。
Single-layer latticed domes belong to structures of imperfection sensitivity. In order to decrease the sensitivity of critical-limit load to the initial geometric imperfection, an optimum design method based on the robust critical-limit load requirement is proposed. The lightest fluctuation of bearing capacity to imperfections is taken as the objective function. We group structural members together according to the sensitivity area of imperfection. The sequence two-stage algorithm is adopted to perform the section optimization design. The structural strength, stiffness, overall stability of double nonlinearity, and initial geometric imperfections are considered as constraints. The optimization results show that, compared with the structures that have not been optimized,the average value of critical-limit loads of optimized structures under 28 imperfections is bigger, and the standard deviation, i.e. the fluctuation of critical-limit loads is smaller. This kind of optimum design can make critical-limit loads of optimized structures possess pretty robustness, and decrease the sensitivity of critical-limit loads to imperfections. At the same time, the consumption of steel was economized