支座激励下小垂度悬索动力响应试验及数值模拟  

Experiment and Numerical Simulation on the Dynamic Responses for Small-sagged Cables Under Support Excitations

作　　者：王国威 张鹏[2] 卢文胜[1] WANG Guowei;ZHANG Peng;LU Wensheng(State Key Lab.of Disaster Reduction in Civil Eng.,Tongji Univ.,Shanghai 200092,China;School of Civil and Surveying&Mapping Eng.,Jiangxi Univ.of Sci.and Technol.,Ganzhou 341000,China)

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]江西理工大学土木与测绘工程学院,江西赣州341000

出　　处：《工程科学与技术》2022年第6期166-175,共10页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(52178501,51638012);山东省高校协同创新重点课题(XTZ201903);江西理工大学校级纵向科研项目(205200100550)。

摘　　要：索网幕墙采光顶通常支承于两相邻结构之间,但主体结构的相对位移振动将作为支座激励导致悬索构件发生过度张拉或松弛现象。为研究悬索在端部支座简谐及随机激励下的动力响应,首先,以综合考虑垂跨比、索力及轴向刚度对悬索振动影响的无量纲变形特征参数αb^(2)为设计变量,对3组悬索试件开展支座简谐激励下的动力响应试验,通过改变激励幅值和激励频率设置两组加载工况,分析在不同的αb^(2)下,悬索位移和索力响应的变化规律;其次,采用ANSYS软件进行数值模拟,计算结果与试验结果吻合较好,验证了数值模拟方法的正确性;最后,以理想高斯白噪声模拟悬索支座随机环境激励,基于已验证的有限元模型计算悬索动力响应,并讨论αb^(2)、阻尼比及激励强度对位移、索力响应谱及均方差的影响。结果表明:1)在支座简谐及随机激励下,悬索位移和索力响应均随αb^(2)、阻尼比的增加而降低,随激励强度的增加而增大;且对于αb^(2)较大的悬索,其位移和索力响应对支座的随机激励更敏感。2)当阻尼比小于0.1时,随着阻尼比的增加,悬索在随机激励下的位移和索力响应分别降低60.9%和67.5%,此阶段下悬索的动力响应对阻尼比变化的敏感性较高,且增加阻尼带来的抑制效果显著。3)当支座简谐激励和索力相同时,垂跨比的变化对悬索的动位移影响较低,但对索力的影响较大,其中垂跨比较小的悬索索力变化更剧烈。The cable-net supported glass roof is commonly located between adjacent structures,however,the relative displacement vibration of the main structure will be considered as the support excitation leading to over-tensioning or relaxation of the small-sagged cables.In order to investigate dynamic responses of small-sagged cables under support harmonic and stochastic excitations.Dynamic responses of three sets of specimens under the support harmonic excitation are tested with the dimensionless deformation parameterαb^(2),as the design variable,which integrates the influence of the sag-span ratio,tensions,and linear stiffness on the vibration of small-sagged cables.The two loading cases are set up by adjusting the loading amplitude and frequency for analyzing displacements and cable tensions under differentαb^(2).Then,by using ANSYS,the calculated results agree well with the experimental results,thus verifying the correctness of the numerical simulation method.Finally,taking the ideal Gaussian white noise as the stochastic excitation,the paper calculates the dynamic response based on the validated numerical model and discusses the effects ofαb^(2),the damping ratio and the excitation intensity on response spectrums and mean square deviations.Results show that:1)Displacements and tension responses under support harmonic and stochastic excitation decrease with increasingαb^(2) and damping ratio,and increase with increasing excitation intensity.Especially for cables with largeαb^(2),their displacement and tension responses are more sensitive to excitations;2)When the damping ratio is less than 0.1,with the increased damping ratio,the displacement and tension responses of the cable under stochastic excitation decrease by 60.9%and 67.5%,respectively,indicating that the dynamic responses under this stage are more sensitive to the damping ratio,and the effect brought by increasing damping is significant;3)When harmonic excitations and cable force are the same,the sagspan ratio has less effect on the dynamic displacement

关 键 词：小垂度悬索 支座 简谐激励 随机激励 动力响应 数值模拟 

分 类 号：TU323.4[建筑科学—结构工程]