基于隔震结构Benchmark模型的复振型叠加反应谱方法  

Complex modal shapes superposition response spectrum approach based on vibration isolation structure benchmark model

作　　者：陈华霆 谭平[1] 彭凌云[2] 李志山[1] 周福霖[1] 

机构地区：[1]广州大学减震控制与结构安全国家重点实验室(培育),广州510405 [2]北京工业大学建筑工程学院,北京100022

出　　处：《振动与冲击》2017年第23期157-163,共7页Journal of Vibration and Shock

基　　金：长江学者和创新团队发展计划(IRT13057)

摘　　要：隔震体系一般由隔震层和上部结构组成,隔震层包括隔震支座和耗能装置,其阻尼特性与上部结构有较大差别。因此,隔震体系阻尼分布具有显著的非比例特性,从而导致其阻尼矩阵不满足无阻尼振型解耦的条件,故在隔震体系中经典的振型叠加反应谱方法已不适用。基于随机振动理论,结合隔震结构的特点,推导了能够考虑非比例阻尼特性的多维地震复振型叠加反应谱方法。针对目前常用的强迫解耦方法,对其误差进行了探讨,发现其阻止了隔震层与上部结构的能量传递,导致上部结构的地震响应偏小。基于隔震结构Benchmark模型对复振型叠加反应谱方法、强迫解耦假定下的反应谱方法、时程分析方法进行了对比,结果表明隔震层阻尼较大时,强迫解耦方法精度较差,并且无法反映隔震层阻尼引起的上部结构地震响应放大效应,复振型叠加反应谱方法计算精度较好,可充分反映隔震结构非比例阻尼的特点。A vibration isolation structure is composed of a superstructure and a vibration isolation layer including vibration isolation bearings and dampers with different damping features from those of superstructure,which possess typically non-proportional damping features. So,the damping matrix of this system can＇t be decomposed via the system＇s undamped modal shapes and the traditional modal shapes superposition response spectrum method is not applicable to this system. Here,based on the random vibration theory and considering features of vibration isolation structures,a multidimensional earthquake complex modal shapes superposition response spectrum method was proposed,it could consider non-proportional damping features. The error of the forced decoupling method,an approximate approach commonly used,was studied. It was found that the energy transfer between the superstructure and the vibration isolation layer is prevented with this method to cause smaller seismic responses of the superstructure. The vibration isolation benchmark model was taken as an example to implement the time-history method,the forced decoupling method and the proposed complex modal shapes superposition response spectrum method,respectively. Three results were compared,it was shown that the proposed method has a better accuracy and can fully reflect the non-proportional damping characteristics in vibration isolation systems; when the damping of the vibration isolation layer is larger,the forced decoupling approach has a worse accuracy,it can＇t reflect the amplification effects of the superstructure seismic responses due to damping of the vibration isolation layer.

关 键 词：反应谱方法 非比例阻尼 复振型叠加方法 强迫解耦方法 隔震结构Benchmark模型 

分 类 号：TU311.3[建筑科学—结构工程]