索桁架结构体系找形分析的节点位移法  

Nodal displacement method for form-finding analysis of cable-truss structure systems

作　　者：田广宇[1] 郭彦林[1] 王昆[1] 

机构地区：[1]清华大学土木工程系,北京100084

出　　处：《空间结构》2011年第3期20-26,共7页Spatial Structures

摘　　要：平面索桁架以及由平面索桁架组成的空间索桁结构是一种应用广泛的柔性结构,它依靠拉索的张力提供刚度.寻找柔性结构合理的预应力分布以达到建筑造型和力学性能的要求是其找形分析的主要目的.与索穹顶结构、单层索网结构相比,索桁架的拓扑关系更加简单明确.力密度法、动力松弛法等一般用于解决单层索网等结构由给定预应力确定初始位形的问题,且难以直接应用在通用有限元软件中(如ANSYS).如果套用索穹顶、单层索网等的找形方法(如力密度法、动力松弛法等)进行找形,则无法直接运用通用有限元软件进行分析.本文依据索桁架结构体系简单明确的拓扑关系,发展了一种通过给节点施加位移进行迭代计算的非线性有限元找形分析方法,该方法不同于单层索网或膜结构找形的小杨氏模量法.本方法求解速度较快,结果较为准确,同时便于在现有的通用有限元软件中应用.Cable-truss and spatial cable structures combined by cable-truss are widely used in flexible structures.Their stiffness depends on cable pre-stresses.It is the main target of form-finding process to find the appropriate distribution of cable pre-stresses which satisfy the requirement of architecture and mechanics.Comparing to cable dome and singular cable net,the topologic property of cable-truss structure system are more simple and explicit.Force Density Method and Dynamic Relax Method are used to solve form-finding problem in singular cable net which aims to find initial configuration from design-reguired pre-stresses,and these methods cannot be applied directly in general finite element software,for example,ANSYS.It would not be available to do form-finding analysis with Force Density Method or Dynamic Relax Method by using general finite element software,while these methods are usually used for form-finding analysis of cable dome or singular cable net.In this paper,nodal displacement method for form-finding analysis is developed based on the simple topologic property of cable-truss structure system,which is different from the method for cable net using small Young＇s modulus.This method＇s solution speed is fast and the obtained result is accurate.It can be easily carried out in general finite element software.

关 键 词：索桁架 找形分析 非线性有限元 迭代 

分 类 号：TU351[建筑科学—结构工程]