基于随机Fourier谱的地震动合成研究  

Synthesis method of non-stationary ground motion based on random Fourier spectra

作　　者：艾晓秋[1] 李杰[2] 

机构地区：[1]同济大学上海防灾救灾研究所,上海200092 [2]同济大学建筑工程系,上海200092

出　　处：《地震工程与工程振动》2009年第2期7-12,共6页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金委创新研究群体科学基金项目(50321803)

摘　　要：本文基于与物理随机模型相对应的随机Fourier谱,通过对地震动非平稳性及其所受影响机制的分析,建立了非平稳地震动合成的新方法。通过引入基本相位差谱,并将初始相角视为随机变量,以相位差谱的分布特性、随机地震动的统计特征以及对结构随机反应的影响为原则,利用计算机程序生成相位差谱,提出了基于随机Fourier谱的合成地震动方法。同时,利用快速FFT技术提高合成精度。根据本文提出的合成方法获得的地震动具有非平稳特性,将为后续研究工作提供合理的地震动加速度时程。Based on the random Fourier spectra corresponding to the physical random earthquake model and considering the character of seismic non-stationarity and the influencing mechanism, this paper proposes a new approach to synthesize the earthquake motion presenting non-stationarity. The basic phase angle difference spectrum is led in and the initial phase angle is regarded as a random variable. The distribution characteristics of the phase angle difference spectrum, the statistical characteristics of random ground motion and the effects on structural stochastic response are the judgment strategy. Utilizing the computation procedure to produce the phase angle difference spectra, a synthetic method is proposed on the basis of the random Fourier spectra. Simultaneously, the fast FFT technique is applied to improve the synthetic accuracy. The proposed method is capable of achieving non-stationary earthquake motion ,which would provide reasonable seismic acceleration for succeeding research work.

关 键 词：随机FOURIER谱 合成地震动 相位差谱 非平稳过程 随机变量 

分 类 号：P315[天文地球—地震学] TU311.3[天文地球—固体地球物理学]