基于连续小波变换的时变结构瞬时模态参数识别
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摘要
为体现时变结构动力特性,定义随机冲击荷载作为时变结构输入激励,提出了基于连续小波变换的时变结构瞬时模态参数识别方法。在短时时变假定条件下,建立基于模局部极大值的连续小波变换时变参数识别原理,利用结构的输出响应进行瞬时模态参数识别,采用三自由度的时变结构体系进行数值模拟,该方法能够准确识别时变结构的瞬时模态参数值。通过设计具有质量参数可变的两层钢框架模型进行测试,验证了方法的有效性与可行性。
In this paper, we propose a method for identifying the instantaneous modal parameters of a time-varying structure based on a continuous wavelet transform. First, we selected a random impact load as the input excitation of a time-varying structure. Then, under the assumed time-varying condition in a short time span, we established a principle for identifying the time-varying parameter based on the continuous wavelet transform. We identified the instantaneous modal parameter using only the output response of the structure, and performed a numerical simulation of a 3-DOF time-varying structure system. The results show that this method can accurately identify the instantaneous modal parameter of a time-varying structure. Finally, we designed and tested a two-layer steel frame model with variable quality parameters, and the results further verified the validity and feasibility of the proposed method.
In this paper, we propose a method for identifying the instantaneous modal parameters of a time-varying structure based on a continuous wavelet transform. First, we selected a random impact load as the input excitation of a time-varying structure. Then, under the assumed time-varying condition in a short time span, we established a principle for identifying the time-varying parameter based on the continuous wavelet transform. We identified the instantaneous modal parameter using only the output response of the structure, and performed a numerical simulation of a 3-DOF time-varying structure system. The results show that this method can accurately identify the instantaneous modal parameter of a time-varying structure. Finally, we designed and tested a two-layer steel frame model with variable quality parameters, and the results further verified the validity and feasibility of the proposed method.
引文
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[2] 杜永峰,赵丽洁,张韬.超长复杂隔震结构施工力学及全过程监测研究[J].工程力学,2015,32(7):1-10.DU Yongfeng,ZHAO Lijie,ZHANG Tao.Study on Construction Mechanics of Long Complicated Isolated Structures And Life-cycle Monitoring[J].Engineering Mechanics,2015,32(7):1-10.
[3] 倪智宇,谭述君,吴志刚.改进的TW-API方法及其在时变模态参数辨识中的应用[J].振动工程学报,2015,28(5):721-729.NI Zhiyu,TAN Shujun,WU Zhigang.An Improved TW-API Recursive Method and Its Application on Time-varying Modal Parmeters Idenfication[J].Journal of Vibration Engineering,2015,28(5):721-729.
[4] YANG W,LIU L,ZHOU S D,et al.Moving Kriging Shape Function Modeling of Vector TARMA Models for Modal Identification of Linear Time-varying Structural Systems[J].Journal of Sound and Vibration,2015,354:254-277.
[5] BISHT S S,SINGH M P.An Adaptive Unscented Kalman Filter for Tracking Sudden Stiffness Changes[J].Mechanical Systems and Signal Processing,2014,49(1-2):181-195.
[6] FELDMAN M.Hilberttransform Methods for Nonparametric Identification of Nonlinear Time Varying Vibration Systems[J].Mechanical Systems and Signal Processing,2014,47(Supp1-2):66-77.
[7] LE T P,ARGOUL P.Continuous Wavelet Transform for Modal Identification Using Free Decay Response[J].Journal of Sound and Vibration,2004,277(Supp1-2):73-100.
[8] 李宏男,孙鸿敏.基于小波分析和神经网络的框架结构损伤诊断方法[J].地震工程与工程振动,2003,23(5):141-148.LI Hongnan,SUN Hongmin.Damage Diagnosis of Framework Structure Based on Wavelet Packet Analysis and Neural Network[J].Earthquake Engineering and Engineering Vibration,2003,23(5):141-148.
[9] 丁幼亮,李爱群,缪长青.基于小波包能量谱的结构损伤预警方法研究[J].工程力学,2006,23(8):42-48.DING Youliang,LI Aiqun,MIU Changqing.Investgation on the Structural Damage Alarming Method Based on Wavelet Packet Energy Spectrum[J].Engineering Mechanics,2006,23(8):42-48.
[10] SU W C,LIU C Y,HUANG C S.Identification of Instantaneous Modal Parameter of Time-varying Systems Via a Wavelet-based Approach and Its Application[J].Computer-Aided Civil and Infrastructure Engineering,2014,29(4):279-298.
[11] 刘景良,任伟新,王佐才,等.基于同步挤压小波变换的结构瞬时频率识别[J].振动与冲击,2013,32(18):37-42.LIU Jingliang,REN Weixin,WANG Zuocai,et al.Instantaneous Frequency Identification Based on Synchrosqueezing Wavelet Transformation[J].Journal of Vibration and Shock,2013,32(18):37-42.
[12] SHI Y,CHANG C C.Wavelet-based Identification of Time-varying Shear-beam Buildings Using Incomplete and Noisy Measurement Data[J].Nonlinear Engineering,2013,2(1-2):29-37.
[13] 赵丽洁,杜永峰,李万润,等.基于小波多分辨率分析的时变结构参数识别[J].工程力学,2016,33(9):94-102.ZHAO Lijie,DU Yongfeng,LI Wanrun,et al.Physical Parameter Identification of Time-varying Structure Based on Wavelet Muli-resolution Analysis[J].Engineering Mechanics,2016,33(9):94-102.
[14] 杨福生.小波变换的工程分析与应用[M].北京:科学出版社,1999.YANG Fusheng.Engineering Analysis and Application of Wavelet Transform[M].Beijing:Science Press,1999.