基于小波能量传递函数谱的结构损伤识别

毛晨曦, 周文松, 欧进萍



作者单位

毛晨曦  

周文松  

欧进萍  



摘要:

为排除小波识别结构频率时地震动频带的干扰,提出了小波能量传递函数谱方法.该方法首先将地震动输入和结构地震反应小波谱分别沿时间轴积分,得到结构输入和输出的小波能量谱;然后将结构反应小波能量谱除以地震动输入小波能量谱,并定义为结构小波能量传递函数谱,该谱的脊线即为结构的时变频率.分别采用小波变换直接识别法和小波能量传递函数谱方法对一幢6层砌体结构在汶川地震一系列余震中的频率变化进行识别.结果表明,结构频率在较大的余震中明显降低,说明结构损伤有进一步发展.该方法可有效排除结构地震反应小波谱中地震动频带的干扰,准确识别结构在地震作用过程中的时变频率.

关键词:  地震  结构余震响应监测  小波能量传递函数谱  损伤识别

DOI：10.11918/j.issn.0367-6234.2011.08.025

分类号:TU312.3

基金项目:中国地震局中央级公益性研究所基本科研业务费资助项目(2007B15);国家自然科学基金资助项目(50808165,90915003)



Damage assessment based on wavelet energy transfer function spectrum

MAO Chen-xi, ZHOU Wen-song, OU Jin-ping

Abstract:

A new wavelet energy transfer function spectrum(WETFS)method was proposed in this study to remove frequency contamination of earthquakes from wavelet spectrum of structural responses in identifying fre-quency variation of structures.First,wavelet spectrums of earthquake excitation and structural response were integrated along time respectively to get wavelet energy spectrum of earthquakes and seismic responses.Then the WETFS was defined by dividing wavelet energy spectrum of earthquake excitation by that of structural re-sponse.The ridge on WETFS just represented the variation of structural frequencies.This method and the tra-ditional wavelet method were both applied on frequency identification of one 6-story masonry apartment build-ing.The seismic responses of this building during series of aftershocks of Wenchuan earthquake were measured and structural frequencies were identified to decrease remarkably during two aftershocks.The results of the two methods indicate that the WETFS method can identify variation of structural frequency accurately without con-tamination of earthquake excitation.

Key words:  earthquake  structural seismic response monitoring  wavelet energy transfer function spectrum  damage identification