【作者】 赵冉；

【导师】 魏德敏；

【作者基本信息】 华南理工大学 ， 防灾减灾工程及防护工程， 2011， 博士

【摘要】 张拉索膜结构的膜褶皱分析与索系失效分析是该类结构荷载态分析中的两个重要方面。通过膜褶皱处理,可以在膜面出现受力褶皱后对结构的荷载响应进行正确的分析。通过索系的失效分析,可以定量分析各构件的重要性并找到结构的薄弱环节,得到结构体系的失效模式和可靠度指标。本文进行了以下研究工作并得到了一些有意义的结论:(1)基于实际的张拉索膜工程中精确的结构形态和索的预张力分布都是未知的这一情况,提出了适时考虑索找力的索膜结构形态分析方法。采用该方法对小型张拉索膜结构及大型张拉索膜工程进行了形态分析,发现该方法可以快速有效的得到合理的结构形态和合适的预张力分布,使索找力和结构找形成为了一个统一的过程。(2)提出了局部坐标系转置和刚度等效分析褶皱膜的方法,该方法通过局部坐标系转置,避免了褶皱单元主应力方向上复杂满秩矩阵的处理问题,给褶皱膜的分析提供了新的思路。采用该方法对马鞍形索膜结构和伞形索膜结构进行了褶皱分析,结果表明该方法可以有效地对褶皱膜进行处理,可得到褶皱单元出现后膜结构正确的荷载响应。(3)为解决膜褶皱分析时的计算发散、精度较低和工程应用等问题,提出了剪切模量归零和刚度等效来分析膜的褶皱的方法。该方法是局部坐标系转置和刚度等效分析法的改进方法,可以在不进行局部坐标系转置的情况下,实现局部坐标系和主应力方向的重合,大大提高了计算效率和计算精度,通过对两个大型膜结构的褶皱分析,发现该方法能快速有效地对大型膜结构进行褶皱处理,解决了膜褶皱分析的工程应用问题。(4)通过对索构件的失效进行研究,提出了采用环比评分法(DARE法)和敏感性分析法相结合的构件重要性分析方法。该方法基于体系刚度变化理论,可定量得到构件的相对重要性系数。根据构件重要性分析结果,提出了关键构件重要性弱化的概念和相关措施。对宝安体育场的分析结果表明,通过对关键索构件的分索处理,可有效降低关键构件的重要性系数,可增多结构的安全防线,提高结构体系的抗倒塌能力。(5)提出了采用路径可靠数寻找索系主要失效模式的方法,该方法通过可靠数这一本文中新定义的概念来判断体系的主要失效构件和寻找主要失效模式。通过对大型索膜结构的失效分析发现,路径可靠数可以直观的反映失效路径在各失效序列上的位置和失效路径的长度,路径平均可靠数可初步判别主要失效模式的序位,可简化结构体系可靠度计算的复杂过程。更多还原

【Abstract】 Wrinkling analysis of membranes and failure analysis of cable systems are two important aspects in load analysis of tensioned cable-membrane structures. By the former, correct load responses can be obtained after appearance of wrinkled elements. By the later, quantitative analysis of the importance of structure members can be achieved, weak structure parts can be identified, failure modes and reliability index can be obtained as well. This paper conducted the following researches and got some valuable conclusions.(1) Since the precise shape and cables’pretension forces of actual cable-membrane project are all unknown, this paper proposes a shape analysis method by which cable force-finding can be considered in appropriate moment through the process of shape-finding. A small cable-membrane structure and a large cable-membrane project are analyzed, it is found that stable shape and proper distribution of pretension forces can be obtained quickly and effectively by this method. It also makes the force-finding and shape-finding a unified process.(2) A method to analyze wrinkled membrane by using the local coordinate system transposition and equivalent stiffness analysis is proposed. The method avoids dealing with the complex problem of full rank matrix in principal stress axe, and provides a new way to process wrinkling analysis. The results of wrinkling analysis of a saddle-shaped cable-membrane structure and an umbrella-shaped cable-membrane structure show that, this method can deal with wrinkled membranes effectively, and can obtain the actual load responses of membranes after the emergence of wrinkles.(3) To solve the divergence, low accuracy problems in membrane wrinkling analysis, and be better applied in practical engineering projects, zero shear modulus plus equivalent stiffness analysis method is proposed. This method is an improvement to the method of local coordinate transposition and stiffness equivalence. The new method can make principal stresses directions coincide with local coordinates without transposing it. The computational efficiency and accuracy are improved significantly. Two large-scale membrane stadium structures are analyzed by this new method, it is found that the method can quickly deal with wrinkles of large membrane structure, and it solves the difficulties of wrinkling analysis application in practical engineering projects.(4) Through analyzing the failure of cables, an important analysis method by combining DARE and sensitivity methods is proposed. The new method, based on system stiffness changing theory, can obtain importance factors quantitatively. According to results of importance analyses, an importance-weaken concept of critical cables by cable-division method is proposed. The calculation results of Baoan stadium show that this method can decrease critical cables’importance factors by cable-division of key cables, it can also increase the safety protection and improve the collapse- resistance capacity of the structural system.(5) A main failure mode finding method using path reliability values is proposed. The method searches main failure members and finds main failure modes via the reliable value which is newly introduced in this paper. A large cable-membrane structure is analyzed by the new method, the results show that the failure arrays position and failure length path can be visually identified according to the reliable value, and the positions of main failure modes can be judged preliminarily. So it can simplify the complex process of reliability calculations.更多还原