基于鲁棒性的索穹顶结构形状优化设计

Shape optimization design of cable-dome structures based on robustness

针对索穹顶结构缺乏有效的鲁棒性分析方法及基于结构鲁棒性能的优化设计现状,首先构建该类结构鲁棒性评价方法,然后结合实际工程案例分析Geiger型、Levy型和Geiger-Levy组合型3类索穹顶结构鲁棒性随结构榀数、环索圈数及矢跨比等形状参数的影响.在此基础上,采用遗传算法,进一步探索基于结构整体鲁棒性能的结构形状优化设计方法.研究发现,3类结构鲁棒性能均随着结构榀数、环索圈数及矢跨比等形状参数的增加而增强,且在相同形状参数设计条件下,Levy型鲁棒性能最强、组合型其次、Geiger型最弱.以Geiger型索穹顶结构平面索桁架撑杆顶部标高、撑杆长度和环索半径3组共6个形状参数为优化变量,在优化变量一定变化范围内(本文取结构初始模型中该值的80%~120%),经形状优化可有效提高鲁棒性(优化率39.8%)及结构抵抗不相称破坏的能力.

In view of the lack of effective robust evaluation method and optimization design theory based on structural robust performance for cable domes,a robust evaluation method for this kind of structure is proposed firstly.Then the effects of structural shape parameters such as the number of plane-unit,the number of hoop cable circle and the rise-span ratio of three types of cable domes,including Geiger,Levy and Geiger-Levy combination cable dome,on the structural robustness are analyzed through an engineering case.On this basis,genetic algorithm is used to further explore the structural shape optimization design method based on the robustness performance of the structure.It is found that the robustness of the three types of cable domes increases as the number of plane-unit,the number of hoop cable circle and the rise-span ratio increase.Under the same condition of shape parameters,Levy cable dome robustness turns out to be the strongest,followed by Geiger-Levy combination cable dome,and the Geiger cable dome is the weakest.Six shape parameters for three groups,namely,strut elevation,strut length and radius of hoop cable,are selected as optimization variables.By optimizing the shape within a certain range of optimization variables,the structural robustness and structural capability to resist disproportional damage can be improved effectively with an optimization rate of 39.8%.