类椭圆形弦支穹顶屋盖选型与设计研究

发布时间：2018-12-21 11:23

【摘要】：本文以宿迁运河体育馆类椭圆形弦支穹顶为工程背景,在前期形状优化研究的基础上,对网格划分、截面优化、索力优化、形状优化、撑杆高度优化等多个因素间的相互影响开展了深化研究,编制基于通用有限元方法的优化程序,通过对比研究的方法得到了兼顾以上多个因素的类椭圆形弦支穹顶的最优结构方案,可做为该类结构的选型和设计的依据。本文的主要结论如下：(1)下弦索预应力分布、上弦网壳截面分布都与类椭圆弦支穹顶结构的最优形状密切相关,根据对背景工程的质量优化结果,这两个因素对优化结果的影响可以达到约11.3%,因此在对类椭圆弦支穹顶进行形状优化时,必须同时考虑索力优化和截面优化,即采用考虑多种因素的形状优化方法。(2)考虑多种因素的形状优化方法,上弦穹顶优化得到的最优外形比不考虑截面优化时的更陡,这与穹顶的受力机理吻合。(3)相同条件下,上弦穹顶的网格划分方式不同,优化得到的外形也会有一定的差异。类椭圆等间距肋环型弦支穹顶结构最优外形的拟合曲线为抛物线；凯威特型和肋环型弦支穹顶结构的最优外形的拟合曲线为四次多项式。(4)与椭圆形弦支穹顶相比,类椭圆形弦支穹顶平面投影在长轴两端更丰满,更方便建筑使用,通过考虑多种因素的性状优化,类椭圆形弦支穹顶每平米的用钢量比椭圆形弦支穹顶结构每平米的用钢量小,采用类椭圆形代替椭圆形有一定优势。(5)类椭圆形弦支穹顶的网格划分主要有等间距肋环型、凯威特型和肋环型三种,根据优化结果,采用等间距肋环型划分的弦支穹顶索单元内力分布更均匀、更合理,且用钢量要优于另外两种网格划分方法,类椭圆形弦支穹顶应优先采用等间距肋环型网格划分。(6)弦支穹顶的撑杆高度直接影响到下弦索系对上弦穹顶的支撑作用,对弦支穹顶的整体性能影响很大,通过撑杆高度优化,可改善结构的受力性能,减小弦支穹顶的用钢量,弦支穹顶优化设计必须考虑撑杆高度的影响。(7)撑杆高度优化结果表明：凯威特型、肋环型和等间距肋环型三种网格划分形式的类椭圆形弦支穹顶结构,各环斜拉索空间位置应基本平行,撑杆与斜拉索的夹角在70到80度之间。(8)对背景工程类椭圆弦支穹顶结构采用考虑多种因素的优化设计得到的结果表明,等间距肋环型划分的用钢量最少,凯威特型次之,肋环型最大,在同类工程中,应优先选用等间距肋环型。
[Abstract]:In this paper, the elliptical domes of Suqian Canal Gymnasium are taken as the engineering background. On the basis of the previous research on shape optimization, the mesh generation, section optimization, cable force optimization and shape optimization are studied. The interaction between several factors, such as height optimization of strut, has been further studied, and an optimization program based on universal finite element method has been developed. By means of comparative study, the optimal structure scheme of ellipsoid dome with multiple factors is obtained, which can be used as the basis for the selection and design of this kind of structure. The main conclusions of this paper are as follows: (1) the distribution of cable prestress and the section distribution of upper chord reticulated shell are closely related to the optimal shape of elliptical chord domes. The influence of these two factors on the optimization results can reach about 11.3. Therefore, in the shape optimization of ellipsoid domes, both cable force optimization and cross-section optimization must be considered. That is to say, the shape optimization method considering many factors is adopted. (2) considering many factors, the optimum shape obtained by the dome optimization is steeper than the one without section optimization. This is consistent with the stress mechanism of the dome. (3) under the same conditions, the meshing of the dome is different, and the optimized shape will be different. The fitting curve is parabola for the optimal shape of the ellipsoid equal-spaced toroidal domes. The fitting curve of the optimal shape of the Kewitt type and the rib ring type chord dome structure is quartic polynomial. (4) compared with the elliptical chordal dome, the ellipsoid domes are more plump at both ends of the long axis and more convenient for building use. By considering many factors, the amount of steel per square meter of elliptical domes is smaller than that of elliptical domes. Using ellipsoid instead of ellipse has some advantages. (5) the meshes of ellipsoid dome are divided into three types: equal spacing rib ring type, Kaiwitt type and rib ring type. The internal force distribution of the cable element of the chord dome is more uniform and reasonable, and the steel content is better than the other two meshing methods. The elliptical domes should be preferentially divided by equal-spacing ribbed ring meshes. (6) the height of the strut of the chord dome directly affects the supporting effect of the lower chord cable system on the upper dome, and has a great influence on the overall performance of the chordal dome. By optimizing the height of the strut, the mechanical performance of the structure can be improved and the amount of steel used in the dome can be reduced. The influence of the height of the brace must be considered in the optimum design of the dome. (7) the result of the optimization of the height of the brace indicates that: Cavette type, The spatial position of each ring stay cable should be basically parallel in three kinds of mesh-like dome structures of rib ring type and equal spacing rib ring type. The angle between strut and stay cable is between 70 and 80 degrees. (8) the optimum design of elliptic chord dome structure of background engineering type by taking into account a variety of factors shows that the amount of steel used in the division of equal spacing rib ring type is the least, followed by Cavette type. The rib ring type is the largest, in the similar projects, the equal space rib ring type should be selected first.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU399

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