给定索矢跨比的张拉式膜结构协同形态分析

COORDINATED FORM-FINDING ANALYSIS OF TENSIONED MEMBRANE STRUCTURES OF GIVEN CABLES' RATIO OF RISE TO SPAN

针对张拉式膜结构整体分析提出了新的求解方法。首先,推导了膜片中索初始预张力的公式;然后,根据现有的索膜非线性有限元找形理论和索杆体系找力方法,提出了用于整体结构协同分析的形态迭代求解法,并编制了相应的程序;最后通过一道算例验证了该文所述方法的正确性,并得到如下结论:按该方法得到的找形结果满足力平衡方程、相容方程和建筑师给定的支座边界条件;满足膜片中索的矢跨比的要求;膜面平衡态的主应力分布状态能够基本达到初始假设主应力分布状态;可以直接获得施工张拉索的理论控制值。

A new solving method of integrate analysis is proposed for tensioned membrane structures. First, formulas of cable＇s initial pretension are derived; second, a new solving method uamed form-finding iteration solution method suitable for form-finding analysis of integrate structures and the program is proposed by means of a non-linear finite element form-finding theory of cable-membrane structures and a prestress-finding method of cable-strut systems. Finally, the method developed herein is validated by one example and some conclusions are made as follows： the form-finding results agree with equilibrium equations, compatibility equations and boundary conditions assigned by architects; the results agree with the ratio of rise to span; requirement of distribution for principal stress of membrane＇s equilibrium state can basically reach the assumptive distribution; theoretical tensioned values for construction can be directly obtained.