索杆张力结构静力位移的近似模态表达与间接测量  

Dynamic-mode based approximate expression and indirect measurement of static deflection of cable-strut tensile structures

作　　者：伍晓顺[1] 邓华[2] 徐思东[1] 马俊[1] 陈剑毅[1] 冯隆琨[1] WU Xiao-shun;DENG Hua;XU Si-dong;MA Jun;CHEN Jian-yi;FENG Long-kun(Nanchang Campus, J iangxi University of Science and Technology, Nanchang 330013, China;Space Structures Research Center, Zhejiang University, Hangzhou 31.0058, China)

机构地区：[1]江西理工大学南昌校区,江西南昌330013 [2]浙江大学空间结构研究中心,浙江杭州310058

出　　处：《空间结构》2018年第2期41-47,共7页Spatial Structures

基　　金：国家自然科学基金项目(51578493);江西省教育厅科学技术研究项目(GJJ170529);江西理工大学博士启动资金项目

摘　　要：预应力贡献的几何刚度和材料贡献的线弹性刚度共同构成索杆张力结构的整体刚度,但既有结构中往往存在不可忽视的预应力偏差、甚至构件损伤,它们可能使结构刚度退化甚至失效.作为柔性结构,索杆张力结构的刚度性能应当被重点监测.而对控制荷载（工况）作用下既有结构的变形进行测量,是评价结构刚度是否发生变化的一个有效手段.但工程实践中一般很难对控制荷载进行大规模且精确加载,因而需要对结构变形进行间接测量.本文发现在给定荷载模式下,索杆张力结构的静力位移总是可以近似表示为少数相同模态（即贡献模态）的线性组合,结构参数变化对静力位移的影响主要体现在贡献模态线性组合系数的变化上,因此既有结构静力位移的监测问题可以转化为贡献模态组合系数的测量问题.本文还发现,通过测量某些满足一定条件的简单荷载所产生的位移,可以间接计算出控制荷载所对应的贡献模态组合系数,从而提高控制荷载所产生变形的测试效率.某Geiger索穹顶算例验证了静力位移近似模态表达式的准确性,以及基于简单荷载的静力测试来间接测量控制荷载所产生变形的可行性.The structural stiffness of cable-strut tensile structures is composed of both the geometrical stiffness and the linear elastic stiffness, which are provided by the pretension and the materials respectively.However,there normally exist inevitable pretension deviations and even member damages.The structural stiffness may thus degenerate and even lose effectiveness.Special attension should be laid on stiffness monitoring for cable-strut tensile structures since they are flexible structures.It is effective to assess whether the structural stiffness changes by measuring the deflections of an existing structure under the dominant loads.However,there exist many difficulties in precisely applying a large-scale dominant load on an existing structure and it is realistic to indirectly measure the deflections caused by a dominant load.In this paper,it is found that the static deflection caused by a specific load can always be approximately expressed as the linear combination of a few fixed dynamic modes（i.e.contribution modes）,of which combination coefficients reflect the influence of structural parameter deviations on thedeflection.As a result,the monitoring of the static deflection for an existing structure is transformed to the measurement of these combination coefficients.It is also discovered that,by testing the deflections caused by some special simple loads,the combination coefficients of the contribution modes under a dominant load can be indirectly calculated.The measuring efficiency for deflection caused by a complicated dominant load can thus be improved.A Geiger cable dome is numerically analyzed and the accuracy of the approximate contribution-mode-based expression of the deflection is verified as well.It is also validated that the deflection caused by a complicated dominant load can be indirectly measured based on some simple load static tests.

关 键 词：索杆张力结构 结构健康监测 刚度性能 动力模态 静力测试 

分 类 号：TU311[建筑科学—结构工程] O329[理学—一般力学与力学基础]