大跨空间结构Rayleigh阻尼系数计算方法  

Calculation method for Rayleigh damping coefficients of large-span spatial structure

作　　者：徐汉勇 余志武[2] XU Hanyong;YU Zhiwu(Department of Civil Engineering,Changsha University,Changsha 410022,China;National Engineering Laboratory for High Speed Railway Construction,Changsha 410083,China)

机构地区：[1]长沙学院土木工程学院,湖南长沙410022 [2]中南大学高速铁路建造技术国家工程实验室,湖南长沙410083

出　　处：《地震工程与工程振动》2019年第5期167-176,共10页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(50938008)~~

摘　　要：大跨空间结构自振频率丰富,空间作用明显,尤其是对于偏心大跨结构,致使在确定Rayleigh阻尼系数时宜考虑振型相关性和地震激励相关性的影响,为此,本文针对大跨空间结构Rayleigh阻尼系数计算方法进行了研究。结合规范反应谱和虚拟激励法,确定任意阶振型对应的激励功率谱强度因子,应用于多维激励多自由体系中,提出了计算多维激励节点位移响应的虚拟激励法,并将积分号和累加号的位置互换,提出了能合理考虑激励相关性和振型相关性对结构响应影响的阻尼系数权重系数及算法,在此基础上,得到了多维激励多阶参考振型Rayleigh阻尼系数计算方法。以双向对称、单向偏心和双向偏心大跨施威德勒型单层球面网壳为例,以四条符合场地的多维地震波作为激励,将基于多种阻尼系数计算方法的结构响应值进行了对比,结果表明:对于双向对称结构,基于各类阻尼系数计算方法的误差均较小,但对于单向偏心结构和双向偏心结构,相比二阶参考振型阻尼系数计算方法和单维激励多阶参考振型阻尼系数计算方法,基于多维激励多阶参考振型阻尼系数计算方法的节点位移误差最大值和截面内力误差最大值均较小,更适用于偏心大跨空间结构阻尼系数的计算。It is necessary for large-span spatial structure to take the influence of modal correlation and the excitation correlation in consideration for the value of Raleigh damping coefficients,because the influences of the both correlations on the structural response are obvious,especially for the eccentric spatial structure.With the necessity,the calculation method for Rayleigh damping coefficients of large-span spatial structure was conducted in the paper.Based on the code response spectrum and the pseudo excitation method,the power spectrum intensity factor correlated to every mode was gotten.Putting the power spectrum intensity factor to the multi degree of freedom system under multi-dimensional excitation,the corresponding pseudo excitation method for nodal displacement was proposed.Based on the position exchange between the integral sign and the accumulative sign of the proposed excitation method,the novel weight coefficient considering the influence of the excitation correlation and the modal correlation to the structural response and the corresponding the calculation method were put forward.With the novel weight coefficient,the calculation method for Rayleigh damping was proposed.Taking three kinds of the large-span schwedler single layer latticed shell for examples,including the symmetric structure,the eccentric structures in one direction or in two directions,the existed method and the above proposed method for Raleigh damping ratio coefficients were put into application with four strong ground motions,and the comparisons among the structural responses from the above three methods for Rayleigh damping coefficients were conducted.The results showed that the errors of the structural response from all the method for Rayleigh damping coefficients were all small,but for the eccentric structures,the maximum values of the nodal displacement errors and the section moment errors from the above proposed method for Raleigh damping ratio coefficients were minimal,and the method was more suitable for the calculation of the

关 键 词：偏心大跨空间结构 Rayleigh阻尼系数 多维激励 权重系数 计算方法 

分 类 号：TU311.3[建筑科学—结构工程]