基于Fibonacci算法的张弦桁架形状参数优化设计研究

发布时间：2018-06-07 13:41

本文选题：张弦桁架 + 形状优化　；参考：《广州大学》2011年硕士论文

【摘要】：张弦桁架结构是通过撑杆连接抗弯、受压构件和抗拉构件,充分发挥拱型的结构受力优势和索材的高抗拉强度的一种结构形式,在国内外得到了广泛的应用。本文以广州国际会展中心等为背景,分析了目前国内外张弦桁架的应用与研究现状;以及总结了张弦桁架优化方面的研究成果,以及有待研究的方面。采用Matlab语言编写出张弦桁架结构通用的有限元模型分析程序。为了使结构受力合理,编程时将张弦桁架的拉索锚固端节点设置在桁架的形心处;求出拉索的内力,对其内力进行验证,以满足拉索是只承受拉力;同时建模时采用相贯节点方式,而相贯节点坐标则采用本文提出的相贯节点坐标修正方案进行处理。通过某算例验证了该程序的有效性。提出了基于离散变量的张弦桁架优化设计方法。首先为了选取最不利工况进行张弦桁架优化设计,编写了张弦桁架结构的各荷载工况程序,采用不同工况对张弦桁架计算模型进行内力、位移分析;其次,为了使优化结果可直接应用于实际工程当中,采用了基于一维搜索算法,对张弦桁架的杆件截面采用离散变量直接从钢管材料库中选取,再对张弦桁架进行优化设计。对某张弦桁架采用本文方法进行了优化设计,并与原张弦桁架进行对比分析,验证了本文提出的优化方法的有效性。对不同跨度的张弦桁架进行了离散变量优化设计,为工程设计提供参考。采用Fibonacci搜索法研究了不同跨度下矢高、垂度、桁架厚度与最小结构重量的相互关系,分析了不同矢高、垂度、厚度对张弦桁架用钢量的影响,采用本文方法搜索出不同跨度的最优矢高、垂度以及桁架厚度,得出了如何选取最优矢高、垂度和厚度的结论。为了提高搜索的效率以及全局最优解,引入了动态搜索区间,有效地解决以上问题。通过对大跨度张弦桁架的离散变量优化算法及形状优化的研究,为张弦桁架的合理设计提供了一种新的途径。
[Abstract]:The Zhang Xian truss structure is a kind of structure form which can make full use of the stress advantage of the arch structure and the high tensile strength of the cable by connecting the flexural, compressive and tensile members with braces, and has been widely used at home and abroad. Based on Guangzhou International Convention and Exhibition Center, this paper analyzes the application and research status of Zhang Xian truss at home and abroad, and summarizes the research results of Zhang Xian truss optimization and the aspects to be studied. A general finite element model analysis program for Zhang Xian truss structures is developed by using Matlab language. In order to make the force of the structure reasonable, the cable anchoring end joints of Zhang Xian truss are set at the center of the truss, the internal force of the cable is calculated, and the internal force of the cable is verified to satisfy the tension of the cable. At the same time, the intersecting node is used in modeling, and the coordinate of the intersecting node is modified by the method proposed in this paper. The validity of the program is verified by an example. An optimal design method for Zhang Xian truss based on discrete variables is proposed. Firstly, in order to select the most unfavorable conditions to carry out the optimal design of Zhang Xian truss, the program of each load condition of Zhang Xian truss structure is compiled, and the internal force and displacement of Zhang Xian truss calculation model are analyzed under different working conditions. In order to make the optimization results directly applicable to practical projects, a one-dimensional search algorithm is adopted, and discrete variables are used to select the member sections of Zhang Xian truss directly from the steel tube material library, and then the optimization design of the Zhang Xian truss is carried out. The optimization design of a certain Zhang Xian truss is carried out by using this method, and compared with the original Zhang Xian truss, the validity of the optimization method proposed in this paper is verified. The discrete variable optimization design of Zhang Xian truss with different span is carried out, which provides a reference for engineering design. Fibonacci search method is used to study the relationship between the minimum weight and the height, sag, thickness of truss, and the influence of different height, sag and thickness on the steel quantity of Zhang Xian truss is analyzed. By using this method, the optimal vector height, sag and truss thickness of different span are obtained, and the conclusion of how to select the optimal vector height, sag and thickness is obtained. In order to improve the efficiency of search and the global optimal solution, the dynamic search interval is introduced to solve the above problems effectively. Through the study of discrete variable optimization algorithm and shape optimization of long-span Zhang Xian truss, a new approach is provided for the rational design of Zhang Xian truss.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TU399

【参考文献】