一种提高时域参数识别精度的新方法
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摘要
在结构损伤识别的时域法研究中,检测的加速度信息中包含结构特征信息和各种干扰信号,积分法计算速度和位移时也可能引入计算中带来的低频信号,使得输出信号严重失真,从而导致反演结构物理参数的失败。为了从测试信息中提取含有结构固有特征的信息,针对小波包分析能对信号频率多层次划分,具有多分辨、高精细的特点,设计一种适用性较强的信号滤波器。该滤波器可根据小波包分解层数,任意确定频率分辨率,选择不同小波包系数,确定滤波频带和频率范围选择。通过剪切型结构物理参数反演模型的算例分析,验证该滤波器具有较好地提取结构特征信息的性能。该滤波器可用于具有此类要求的信号处理。
In time domain identification of structural parameters the source signals picked up by acceleration sensors are often noise contaminated,from which the derived velocity or displacement signals may be further distorted through integration.Such a kind of seriously distorted input signals can worsen and even cause the failure of parameter identification.Hence,the first thing for improving parameter identification is to improve the quality of source signals.A filtering technique based on wavelet packet analysis is introduced.In connection with that wavelet packet analysis is featured with high precision and multi-level resolution,a widely applicable filter can be readily designed with specific resolution for different selections of filtering frequency band,so that the filtered source signal can meet the desired requirements.Numerical results of an illustrative example on parameter identification of a shear column model structure show the feasibility and effectiveness of this filtering technique.
In time domain identification of structural parameters the source signals picked up by acceleration sensors are often noise contaminated,from which the derived velocity or displacement signals may be further distorted through integration.Such a kind of seriously distorted input signals can worsen and even cause the failure of parameter identification.Hence,the first thing for improving parameter identification is to improve the quality of source signals.A filtering technique based on wavelet packet analysis is introduced.In connection with that wavelet packet analysis is featured with high precision and multi-level resolution,a widely applicable filter can be readily designed with specific resolution for different selections of filtering frequency band,so that the filtered source signal can meet the desired requirements.Numerical results of an illustrative example on parameter identification of a shear column model structure show the feasibility and effectiveness of this filtering technique.
引文
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10胡昌华,张军波,夏军,张伟.基于MATLAB的系统分析与设计:小波分析.西安:西安电子科技大学出版社,2001.HU ChangHua,ZHANG JunBo,XIA Jun,ZHANG Wei.System analysis and design based on MATLAB.Xi′an:Xidian University Press,2001(In Chinese).
2陈隽,李杰.部分输入未知条件下的结构系统识别研究.地震工程与工程振动,1998,18(4):40～47.CHEN Jun,LI Jjie.Study of structural system identification with incomplete input information.Earthquake Engineering and Engineering Vibration,1998,18(4):40～47(In Chinese).
3李杰,陈隽.未知输入条件下的结构物理参数识别研究.计算力学学报,1999,16(1):32～40.LI Jie,CHEN Jun.Study on identification of structural dynamic parameters with unknown input information.Chinese Journal of Computational Mechanics,1999,16(1):32～40(In Chinese).
4谢献忠,易伟建.全量补偿复合反演算法的改进及其应用.工程力学,2005,22(1):28～32.XIE XianZhong,YI WeiJian.Updated total compensation method for solving composite inversion problem of structural dynamic system.Engineering Mechanics,2005,22(1):28～32(In Chinese).
5谢献忠.基于周期统计平均的结构动力复合反演研究.振动与冲击,2004,23(3):46～49.XIE XianZhong,YI WeiJian.Compositeinversion of structural dynamic systembased on ideas of periodic load statistical average.Journal of Vibration and Shock,2004,23(3):46～49(In Chinese).
6Fairouz Bettayeb,Sofiane Haciane,Sali m Aoudia.Improving the ti me resolution and signal noise ratio of ultrasonic testing of welds by the wavelet packet.NDT&EInternational,2005,38(6):478～484.
7Klein R,Ingman D,Braun S.Non-stationary signals:phase-energy approach——theory and si mulations.Mechanical Systems and Signal Processing,2001,15(6):1061～1089.
8李弼程.小波分析及其应用.北京:电子工业出版社,2003.LI BiCheng.Wavelet analysis and application.Beijing:Electronics Industry Press,2003(In Chinese).
9张光新,崔扬,周泽魁.基于小波包分解的纹理图像去噪.华南理工大学学报,2005,(3):31～33.ZHANG GuangXin,CUI Yang,ZHOU ZeKui.Denoising of texture i mages based on wavelet packet decomposition.Journal of South China University of Technology,2005,(3):31～33(In Chinese).
10胡昌华,张军波,夏军,张伟.基于MATLAB的系统分析与设计:小波分析.西安:西安电子科技大学出版社,2001.HU ChangHua,ZHANG JunBo,XIA Jun,ZHANG Wei.System analysis and design based on MATLAB.Xi′an:Xidian University Press,2001(In Chinese).
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