大跨网壳地震反应时Rayleigh阻尼构建方法比较

发布时间：2019-03-01 17:09

【摘要】：为研究Rayleigh阻尼系数参考频率选取方法对结构地震反应的影响,以一个长85.2 m,宽61.8 m的网壳为例,对比分析了基于地震波频谱特性选取第二个参考频率的方法、Idriss方法、传统方法、优化方法所得Rayleigh阻尼系数引起顶点位移和基底剪力计算误差.对于地震波的频谱特性,讨论了拟加速度反应谱、拟速度反应谱、位移反应谱的峰值频率和形心点频率的统计范围.数值计算结果表明:基于拟速度反应谱、位移反应谱峰值频率和形心频率以及Fourier谱的峰值频率所得Rayleigh阻尼将使计算结果偏小;用小于基本周期范围内的拟加速度反应谱的峰值频率或形心点频率作为第二个参考频率计算误差较小;当地震波的卓越频率大于基频的结构时,Idriss方法用平滑化Fourier谱的卓越频率计算参考频率效果更好;优化方法可以直接得到Rayleigh阻尼系数,避免了人为选取参考频率的任意性,且计算精度高.
[Abstract]:In order to study the influence of reference frequency selection method of Rayleigh damping coefficient on seismic response of structures, a lattice shell with a length of 85.2 m and a width of 61.8 m is taken as an example, and the method of selecting the second reference frequency based on the spectrum characteristics of seismic waves is compared and analyzed. The Rayleigh damping coefficient obtained by Idriss method, traditional method and optimization method results in the calculation error of vertex displacement and base shear force. For the spectral characteristics of seismic waves, the statistical range of pseudo-acceleration response spectrum, pseudo-velocity response spectrum, peak frequency of displacement response spectrum and centroid frequency is discussed. The numerical results show that based on the pseudo-velocity response spectrum, the peak frequency and centroid frequency of displacement response spectrum and the peak frequency of Fourier spectrum, the Rayleigh damping will reduce the calculated results. Using the peak frequency or centroid frequency of pseudo-acceleration response spectrum within the range of basic period as the second reference frequency, the calculation error is small. When the dominant frequency of the local seismic wave is greater than that of the fundamental frequency, the Idriss method is better for calculating the reference frequency by smoothing the superior frequency of Fourier spectrum. The Rayleigh damping coefficient can be obtained directly by the optimization method, which avoids the arbitrariness of artificial selection of the reference frequency, and the calculation accuracy is high.
【作者单位】：北京科技大学土木系;土木工程防灾国家重点实验室(同济大学);
【基金】：土木工程防灾国家重点实验室开放基金(SLDRCE15-01)
【分类号】：TU399

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