自由曲面索支撑空间网格结构形态优化  

Shape optimization of free-form cable-braced grid shells

作　　者：冯若强[1,2] 葛金明[1] 叶继红[1] 

机构地区：[1]东南大学混凝土与预应力混凝土结构教育部重点实验室,江苏南京210096 [2]中国矿业大学江苏省土木工程环境灾害与结构可靠性重点实验室,江苏徐州221008

出　　处：《土木工程学报》2013年第4期64-70,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(50908044;51278117);国家杰出青年基金(51125031);江苏省自然科学基金(SBK201123270);江苏省土木工程环境灾变与结构可靠性重点实验室开放基金(2011KA05)

摘　　要：索支撑空间网格结构是一种新型的单层网壳形式,主要应用于玻璃采光顶结构中。由于目前对自由曲面索支撑空间网格结构形态方面的研究国内外还相对较少,为此提出了一套适用于该类结构的形态优化方法。该优化方法采用结构整体应变能为优化目标、结构高度为优化变量、共轭梯度法为优化算法。根据索支撑空间网格结构的建模方法,将优化结构整个曲面转化为优化结构的准线和母线。采用该方法对自由曲面索支撑空间网格结构进行形态优化研究,得到结论如下:首先,采用本文形态优化方法,收敛速度快,形态优化后结构的力学性能提高很大;其次,形态优化过程中平面四边形网格属性不变,优化变量少;最后,对优化后的离散网格重新进行拟合生成曲面,对该曲面重新划分网格,保证网格长度相等。重新划分网格为结构构件加工和施工提供了便利,而且结构力学性能削弱不大。Cable-braced grid shells, as a new type of single-layer reticulated shell, are widely used in glass roofs. However, research on the shape optimization of free-form cable-braced grid shells is relatively rare, so a shape optimization method for cable-braced free-form grid shells was proposed. In this method, the strain energy was taken as the optimization object, structural height used as the optimization variable, and the conjugate gradient method adopted as the optimization algorithm. According to the shape forming method for grid shells, their shape optimizations can be realized only by adjusting the generatrix and directrix, instead of optimizing the whole surface. The tbllowing conclusions can thus be drawn. Firstly, the structural mechanical behavior of grid shells can be significantly improved by using the fast convergent shape optimization method. Secondly, the plane quadrilateral mesh is maintained and few optimization variables are required in the proposed shape optimization method. Finally, the optimized surface of the grid shell is re- meshed to get the same meshes, so it is very convenient to manufacture and build the grid shells, while the structural mechanical behavior is little affected.

关 键 词：自由曲面 共轭梯度法 空间网格结构 形态优化 

分 类 号：TU393[建筑科学—结构工程]