【作者】 蒋欣； 任伟新；

【Author】 Jiang Xin Ren Weixin (School of Civil Engineering and Architecture,Central South University,Changsha,410075)

【机构】 中南大学土木建筑学院；

【摘要】 地震动是典型的非平稳随机过程,其非平稳特性对结构响应影响极大。按照Priestly提出的演变随机过程理论,基于小波变换的方法推导出演变功率谱密度函数。数值分析中以离散尺度上Morlet小波函数为母小波,通过对以金井清谱为功率谱的随机过程做多尺度小波变换,估计出演变谱和瞬时均方值,与精确值对比,证明了方法的正确性。通过分析演变谱,有效识别出地震动在时频域上的强度非平稳与频率非平稳特性,从瞬时均方值中亦识别出地震动能量随时间的变化。更多还原

【Abstract】 Earthquake motions are regarded as the typical non-stationary stochastic processes,and such non-stationary characteristics influence the structural response greatly.According to the theory of evolutionary spectra presented by Priestly,the evolutionary power spectral density is estimated,based on wavelet transform.In the numerical analysis,the Kanai-Tajimi seismic spectrum is considered.The evolutionary spectra and the instantaneous mean square value are estimated through the Morlet transform of the process on discretized multi-scales.Numerical example demonstrates the accuracy of the proposed method.Through the analysis of evolutionary spectra,the non-stationary characteristics of both intensity and frequency in the time-frequency domain are identified,and the change of the seismic energy along the process is reflected from the instantaneous mean square value.更多还原