Lamb Wave Arrival Time Extraction Using Hilbert-Huang Transform for Improved Tomography Image  

作　　者：张海燕 孙修立 樊仕轩 

机构地区：[1]Key Laboratory of Specialty Fiber Optics and Optical Access Networks,School of Communication and Information Engineering,Shanghai University

出　　处：《Journal of Donghua University(English Edition)》2009年第5期503-508,共6页东华大学学报（英文版）

基　　金：National Natural Science Foundation of China(No.10504020,10874110);Shanghai Leading Academic Discipline Project,China(No.S30108);Science and Technology Commission of Shanghai Municipality,China(No.08DZ2231100)

摘　　要：Travel time Lamb wave tomography has been shown to be an effective nondestructive evaluation （NDE） technique for plate-like structures. The methods used previously to extract arrival times of the fastest or multi Lamb wave modes are mostly based on various timefrequency methods such as Wigner-Ville distribution, shorttime Fourier transform, and recently explored wavelet transform（WT）. Frankly speaking, uses of these signal processing methods improve the accuracy of the arrival time extraction to a great extent relative to directly extract arrival times in time-domain from Lamb waveforms. Hilbert-Huang transform（HHT） is also an efficient way for analyzing and processing non-stationary signals. The resolving power of time and frequency is restricted from Heisenberg principle in wavelet analysis, while in HHT, the time resolving power is precise and steady, and frequency resolving power is adaptive according to signal intrinsic characteristics. Conclusion can be made that the HI-IT method is more adaptive than WT anal;/sis in ~.!~M~ zing non-stationary signals. Based on the abo~, ~tiaf method is attempted to extract arrival times from Lamb waveforms in this paper. The Lamb wave tomography images generated with arrival times from HHT method were compared with those of WT. The results show that the new method improves the quality of tomography image, which demonstrates the applicability of HHT method in extracting arrival times of Lamb waves.Travel time Lamb wave tomography has been shown to be an effective nondestructive evaluation (NDE) technique for plate-like structures.The methods used previously to extract arrival times of the fastest or multi Lamb wave modes are mostly based on various time-frequency methods such as Wigner-Ville distribution,short-time Fourier transform,and recently explored wavelet transform(WT).Frankly speaking,uses of these signal processing methods improve the accuracy of the arrival time extraction to a great extent relative to directly extract arrival times in time-domain from Lamb waveforms.Hilbert-Huang transform(HHT) is also an efficient way for analyzing and processing non-stationary signals.The resolving power of time and frequency is restricted from Heisenberg principle in wavelet analysis,while in HHT,the time resolving power is precise and steady,and frequency resolving power is adaptive according to signal intrinsic characteristics.Conclusion can be made that the HHT method is more adaptive than WT analysis in analyzing non-stationary signals.Based on the above,HHT method is attempted to extract arrival times from Lamb waveforms in this paper.The Lamb wave tomography images generated with arrival times from HHT method were compared with those of WT.The results show that the new method improves the quality of tomography image,which demonstrates the applicability of HHT method in extracting arrival times of Lamb waves.

关 键 词：Lamb waves TOMOGRAPHY Hilbert-Huang transform nondestructive evaluation 

分 类 号：TP206[自动化与计算机技术—检测技术与自动化装置] TN929.53[自动化与计算机技术—控制科学与工程]