摘要
为分析隔震层阻尼对隔震结构减震效果的影响规律,以简谐激励下的结构响应为理论基础,通过绘制单自由度结构在ATC-63推荐的地震波作用下的标准加速度反应谱和傅里叶谱,深入分析阻尼变化的情况下减震效果的影响因素。在对单自由度结构分析的基础上,利用有限元软件设计了采用黏滞阻尼隔震支座的多自由度结构,考察在隔震结构在不同的地震波作用下隔震层阻尼比变化对减震效果的影响。研究表明,阻尼对多自由度隔震结构的影响规律与单自由度是一致的,都与隔震周期和地震波的频谱特性有关;地震波傅里叶谱中出现峰值处近似于一个简谐激励,由于共振效应,对于隔震周期在激励周期附近的结构,增大阻尼比会减小加速度响应,当隔震周期大于激励周期的2^(1/2)倍以上时,由于放大效应,增加隔震层的阻尼将会导致其绝对加速度响应的增大,没有减震效果。
In order to analyze the influence of isolation layer damping on damping effect, based on structural response under harmonic excitation, the acceleration response spectra and Fourier spectra of the SDOF structure under the action of ATC - 63 - recommended seismic waves are derived, and factors associated with the seismic reduction effectiveness in conditions of different damping are analyzed. On the basis of SDOF structure and by using the finite element software,the multi-degree-of-freedom structure with viscous damping isolation bearing is designed. The effects of the damping ratio of the isolation layer on the seismic reduction of the isolated structure under different seismic waves are studied. The results show that the influence of damping on multi-degrees of freedom isolation structure is consistent with the SDOF structure and is related to isolated structure period and the characteristics of frequency spectrum. The peak value of the Fourier spectrum of the seismic wave is similar to a harmonic excitation. Due to the resonance effect, the increase of the damping ratio will reduce the acceleration response for the structure near the excitation period. When the isolation period is √2 Times longer than the excitation period, because of the amplification effect, the increasing the damping of the isolation layer will lead to an increase of its absolute acceleration response, which means that there is no shock absorption effect.
作者
李修远
彭凌云
Li Xiu-yuan Peng Ling-yun(Beijing Key Lab of Earthquake Engineering and Structural Retrofit, Beijing University of Technology, Be ifing 100124, China)
出处
《工程抗震与加固改造》
北大核心
2017年第4期35-40,54,共7页
Earthquake Resistant Engineering and Retrofitting
关键词
黏滞阻尼
隔震结构
加速度响应
影响规律
viscous damping
isolated structure
acceleration response
influence rule
