基于S变换的地震波时频分析及人工调整  

Time-frequency analysis and artificial simulation of earthquake ground motions via S-transform

作　　者：樊剑[1] 吕超[1] 张辉[1] 

机构地区：[1]华中科技大学土木工程与力学学院

出　　处：《振动工程学报》2008年第4期381-386,共6页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(50778079);湖北省自然科学基金资助项目(2006ABA067)

摘　　要：首先推导了离散S变换的基本算法,定义了反映地震波时频特性的时变幅值谱和时变能量谱;以K obe地震波为例,基于S变换分析了该地震波的时频特性,并对采用不同窗口函数的分析结果进行了对比,分析发现当适当地调整窗口参数,复窗口的广义S变换对非平稳地震波有较好的时频分辨率;利用S变换的时频滤波性质,对实际地震波进行了任意时间和频率段的人工调整;以与抗震规范相容的功率谱为目标谱,提出了利用S变换合成非平稳地震波的新方法,通过实例分析发现,人工合成的地震波功率谱与目标谱符合很好,而且继承了母波的非平稳特性;还研究了地震波的时频特性对单自由度体系弹性反应谱的影响。The formulas of discrete S-transform are derived, and the time-varying amplitude spectrum and time varying energy spectrum based on S-transform are given. The time-varying energy spectrum of Kobe wave is estimated by using S-transform with different window function, numerical results show that the improved S-transform is the effective method when choosing the time window parameter properly. Earthquake records can be adjusted with time-frequency filtering based on S-transform, and a new procedure is presented to generate an accelerograms whose power spectrum is compatible with a target spectrum by using actual earthquake records as parents. It is showed that the power spectrums of reconstructed accelerograms have good matching with the target spectrum and preserve the non-stationary features of the parents accelerograms. Finally, the effects of the non-stationary frequency characteristic of ground motions on the response spectrum are investigated.

关 键 词：S变换 地震波 时变谱 功率谱 

分 类 号：P631.443[天文地球—地质矿产勘探] TU375.404[天文地球—地质学]