基于模态修复的索网结构关键刚度补偿方法  

An approach for compensating key stiffness of cable net structures by modal rehabilitation

作　　者：王新涛 邓华[1,3] 刘宏创[1,3] 诸德熙 WANG Xintao;DENG Hua;LIU Hongchuang;ZHU Dexi(Space Structures Research Center,Zhejiang University,Hangzhou 310058,China;China Energy Engineering Group Zhejiang Electric Power Design Institute Co.,Ltd,Hangzhou 310012,China;Zhejiang Provincial Key Laboratory of Spatial Structures,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学空间结构研究中心,浙江杭州310058 [2]中国能源建设集团浙江省电力设计院有限公司,浙江杭州310012 [3]浙江大学浙江省空间结构重点实验室,浙江杭州310058

出　　处：《建筑结构学报》2021年第7期76-84,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51578493)。

摘　　要：通过动力模态测试可以便于监测索网结构的刚度。通常仅需测试少量目标模态即可评价对主控荷载作用下的结构变形起主要抵抗作用的关键刚度。针对由预应力偏差引起的结构刚度退化问题,提出了通过补张拉来修复目标模态以实现索网结构关键刚度补偿的方法,建立了索网结构预张力偏差、单元长度误差与结构刚度矩阵变化之间的解析关系,分析了目标模态参数修复与结构关键刚度补偿间的理论关系。给出了一种密频区域内目标模态集合的简便扩展方法。基于矩阵摄动理论,建立了补张拉索的索长调整量与目标模态参数变化量间的方程。对于限定补张拉索数量的情况,采用补张拉索的优选策略以提高目标模态参数的修复精度。利用所提出的方法对一个具有预应力偏差的马鞍形索网结构算例进行了补张拉分析。计算结果表明,通过目标模态修复和补张拉索优选可以有效实现索网结构关键刚度偏差的补偿。The dynamic modal testing is technically convenient for the stiffness monitoring of cable net structures. The key stiffness, which provides the main resistance to the deformation caused by the dominant loads in the design of cable net structures, can be evaluated only by testing a small number of target modes. Concerning the stiffness degradation caused by pretension deviations, an approach is proposed for compensating the key stiffness of cable net structures by rehabilitating the target modes. The analytical expressions among pretension deviations, cable length errors and variation of structural stiffness matrix are established. The relationship between the rehabilitation of target modes and the compensation of key stiffness is analyzed theoretically. A simplified method is given to expand the set of target modes, which are located in the region of dense modes. The relationship between the length adjustment of re-stretched cables and the variation of target modes is established based on the matrix perturbation theory. When the number of re-stretched cables is given, a strategy for selecting the optimal re-stretched cables is developed to improve the rehabilitation accuracy of modal parameters. Using the proposed approach, a re-stretching analysis is carried out for an illustrative saddle-shaped cable net structure with pretension deviations. The results reveal that the key stiffness deviation of cable net structures can be compensated effectively by rehabilitating target modes and optimally selecting re-stretched cables.

关 键 词：索网结构 动力模态测试 刚度补偿 模态修复 补张拉索优选 

分 类 号：TU399[建筑科学—结构工程]