大跨度索网与网壳结构的有限元分析

发布时间：2018-05-23 18:01

本文选题：索网结构 + 找形分析　；参考：《湖北工业大学》2017年硕士论文

【摘要】：空间结构在我国建筑的应用中越来越多,且结构形式也逐渐多样化,跨度越来越大,不少研究人员提出各种方法对空间结构进行实验研究和模拟分析,这些研究都很好的促进了空间结构的发展。根据刚度差异将空间结构分为柔性空间结构和刚性空间结构,分别对空间结构中具有代表性的索网结构和网壳结构进行有限元分析。其中索网结构是典型的柔性空间张拉结构,这种结构几何形状不确定,需要施加预应力之后才会形成初始的几何状态,才能承受外载荷的作用,索网结构形状的确定成为对索网结构进行分析时关键的一步。而网壳结构是刚性的空间网格结构,与传统的结构相同的是它有固定的几何形状,但它比传统结构跨度更大,受力更合理。当网壳结构跨度越来越大,所用材料越来越轻质时,稳定性问题成为网壳结构,尤其是单层球面网壳最重要的问题。本文主要的研究内容分为两个部分,分别是以FAST天文望远镜主索网结构为实例进行的找形分析和以凯威特K8型单层球面网壳结构为实例进行的非线性稳定性分析。以下从三个方面阐述本文的研究内容:(1)基于大型通用有限元软件,运用APDL参数化设计语言编辑FAST主索网结构的建模程序,并构建FAST主索网结构的计算模型。(2)选择逆迭代法对索网结构进行初始形态的分析,并对结构不均匀的内力分布利用“等拉力替换法”做截面的优化。(3)运用有限元分析软件,对凯威特K8型单层球面网壳结构进行了非线性稳定性分析,其中对比考虑初始缺陷与不考虑初始缺陷状态下的状态,得出网壳结构的荷载-位移曲线,通过对曲线的分析来说明初始缺陷对网壳结构稳定性的影响。论文对迭代法进行了探讨并将其应用于索网结构的初始形态分析中,找力的结果表明,逆迭代法是可以应用于大跨度索网结构初始形态分析中去的。而通过对比考虑初始缺陷和不考虑初始缺陷情况下的非线性稳定极限荷载系数,同时对比了不同初始缺陷下的荷载系数,得出初始缺陷值越大时,结构的稳定性越差的结论,对于大跨度网壳结构的稳定性设计有一定的理论参考作用。
[Abstract]:The application of spatial structure in Chinese architecture is more and more, and the form of structure is becoming more and more diversified, and the span is becoming larger and larger. Many researchers put forward various methods to carry on the experimental research and simulation analysis to the spatial structure. These studies have promoted the development of spatial structure. According to the stiffness difference, the spatial structure is divided into flexible spatial structure and rigid spatial structure. The representative cable-reticulated structure and latticed shell structure in spatial structure are analyzed by finite element method, respectively. The cable net structure is a typical flexible space tensioning structure. The geometric shape of the structure is uncertain, and the initial geometric state can only be formed after the application of prestress, so that the cable net structure can bear the effect of external load. The determination of the shape of cable-net structure is a key step in the analysis of cable-net structure. The reticulated shell structure is a rigid spatial grid structure, which has a fixed geometric shape, but it has a larger span and a more reasonable force than the traditional structure. When the span of latticed shell is increasing and the material used is becoming lighter and lighter, the stability problem becomes the most important problem for reticulated shell structure, especially for single-layer spherical reticulated shell. The main research contents of this paper are divided into two parts, one is the shape finding analysis based on the main cable net structure of the FAST telescope and the other is the nonlinear stability analysis of the Kwett K8 single-layer spherical reticulated shell structure as an example. Following are three aspects of the research content of this paper: (1) based on the large-scale general finite element software, using APDL parametric design language to edit the modeling program of FAST main cable network structure. The calculation model of FAST main cable net structure is constructed. (2) the inverse iteration method is chosen to analyze the initial shape of cable net structure, and the uneven internal force distribution is optimized by "equal tension replacement method" by using finite element analysis software. In this paper, the nonlinear stability analysis of K8 single-layer spherical reticulated shell structure is carried out. The load-displacement curve of the latticed shell structure is obtained by comparing the initial defects with those without initial defects. The influence of initial defects on the stability of latticed shell structures is illustrated by the analysis of the curves. This paper discusses the iterative method and applies it to the initial shape analysis of cable-net structures. The results of force finding show that the inverse iterative method can be applied to the initial morphological analysis of long-span cable-net structures. By comparing the nonlinear stability limit load coefficients with and without initial defects and comparing the load coefficients with different initial defects, it is concluded that the greater the initial defect value is, the worse the stability of the structure is. It can be used as a theoretical reference for the stability design of long span latticed shell structures.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU399

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