双线性时频分布交叉项提取及损伤识别应用  

Cross-Term Extraction from Bilinear Time-Frequency Distributions and Application in Structural Damage Detection

作　　者：闫维明[1] 马裕超[1] 何浩祥[1] 石鲁宁 

机构地区：[1]北京工业大学工程抗震与结构诊治北京市重点实验室,北京100124

出　　处：《振动．测试与诊断》2014年第6期1014-1021,1166,共8页Journal of Vibration,Measurement & Diagnosis

基　　金：国家自然科学基金资助项目(51108009);高等学校博士学科点专项科研基金资助项目(20111103110015;20111103120022)

摘　　要：对信号时频分析方法进行了综述,并比较了线性时频分布及以Wigner-Ville(简称WVD)分布为代表的双线性时频分布的特性。论证了交叉项的存在及其在结构损伤识别中应用的价值,提出采用短时傅里叶谱图与WVD内积提取主项的方法,构建了二维时频转换矩阵,进而获得完整的交叉项并可利用交叉项的分布特性实现结构损伤识别。通过理论论证并结合梁式结构试验和仿真模拟,表明利用交叉项幅值变化率可以准确识别出结构损伤部位和程度,验证了利用双线性时频分布的交叉项进行损伤识别的有效性,为工程结构损伤识别提供了一种可靠的分析方法。Abundant damage information is implicated in the bilinear time-frequency distribution of structural dynamic signals,which could provide effective support for structural damage identification.Signal time-frequency analysis methods are reviewed,and the characteristics of linear time-frequency distribution and bilinear time-frequency distribution,typically represented by the Wigner-Ville distribution,are compared.The existence of the cross-term and its application in structural damage detection are demonstrated.A method of extracting the dominant term is proposed that combines the short-time flourier spectrum and Wigner-Ville distribution.Then a two-dimensional time-frequency transformation matrix is constructed,and the complete cross-term is extracted.The distribution character is in favor of the structural damage identification.Through theoretical analysis,model experiments and numerical simulation of the girder structure,the change rate of the cross-term amplitude is validated to identify the damage location and degree.The effectiveness of the cross-term of the bilinear time-frequency distribution for damage detection is confirmed,and the analytical method of damage identification used in structural engineering is available.

关 键 词：损伤识别 时频分析 双线性时频分布 WIGNER-VILLE分布 交叉项 

分 类 号：TU311.3[建筑科学—结构工程] TU317.1