基于VMD和广义Morse小波的结构瞬时频率识别  

Instantaneous Frequency Identification of a Structure Using Variational Mode Decomposition and Generalized Morse Wavelets

作　　者：王超 毛羚[2] WANG Chao;MAO Ling(School of Civil Architecture and Environment,Hubei University of Technology Wuhan,430034,China;School of Civil Engineering and Architecture,Wuhan University of Technology Wuhan,430070,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,武汉430034 [2]武汉理工大学土木工程与建筑学院,武汉430070

出　　处：《振动．测试与诊断》2020年第5期957-962,1026,共7页Journal of Vibration,Measurement & Diagnosis

基　　金：国家自然科学基金资助项目(51408250,51708188);湖北工业大学博士科研启动基金资助项目(BSQD14043)。

摘　　要：提出了基于变分模态分解和广义Morse小波相结合的时变结构瞬时频率识别方法。首先,针对噪音干扰问题,提出了快速阈值迭代算法,通过将信号转换到小波域,利用信号稀疏特性进行降噪;然后,提出了基于变分模态分解和广义Morse小波的时变参数识别理论,采用数值算例验证了提出方法的有效性和精度;最后,设计了一个具有时变特性的移动小车试验,进行模态试验对结构有限元模型进行校正。采集小车通过主梁时的应变和加速度响应,由应变数据估算小车不同时刻在梁上的位置,对加速度响应数据进行分析识别结构的瞬时频率,与有限元计算的结果进行对比分析。结果表明,提出的方法可以有效准确地识别时变结构瞬时频率。Civil engineer usual appear time-varying characteristic,it is very important to identify instantaneous frequency for structural health monitoring and safety evaluation.A method about instantaneous frequency identification of a structure based on variational mode decomposition(VMD)and generalized morse wavelets(GMW)is proposed.Firstly,fast iterative shrinkage-thresholding algorithm is used to reduce noise,which utilize the sparse feature of signal by transforming to wavelet region.And then,an identification theory of time-varying parameter based on VMD and GMW is presented.A numerical stimulation is used to validate the effectiveness of the method.Finally,an experiment model of moving vehicle across a beam is built.The modal test is proceed and the finite element model is calibrated.The measured stain data is used to estimate the position of vehicle on beam at any time,and the accelerate response is used to identify the instantaneous frequency by proposed method.The results show that the proposed method has good validation and accuracy to identify the instantaneous frequencies.

关 键 词：时变结构 瞬时频率 小波变换 广义Morse小波 快速阈值迭代 变分模态分解 

分 类 号：TH70[机械工程—仪器科学与技术] TU317.1[机械工程—精密仪器及机械]