Time reversal technique for health monitoring of metallic structure using lamb waves

Gangadharan, R. ; Murthy, C. R. L. ; Gopalakrishnan, S. ; Bhat, M. R. (2009) Time reversal technique for health monitoring of metallic structure using lamb waves Ultrasonics, 49 (8). pp. 696-705. ISSN 0041-624X

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.ultras.2009.05.002


Time reversal active sensing using Lamb waves is investigated for health monitoring of a metallic structure. Experiments were conducted on an aluminum plate to study the time reversal behavior of A0 and S0 Lamb wave modes under narrow band and broad band pulse excitation. Damage in the form of a notch was introduced in the plate to study the changes in the characteristics of the time reversed Lamb wave modes experimentally. Time–frequency analysis of the time reversed signal was carried out to extract the damage information. A measure of damage based on wavelet transform was derived to quantify the hidden damage information in the time reversed signal. It has been shown that time reversal can be used to achieve temporal recompression of Lamb waves under broadband signal excitation. Further, the broad band excitation can also improve the resolution of the technique in detecting closely located defects. This is demonstrated by picking up the reflection of waves from the edge of the plate, from a defect close to the edge of the plate and from defects located near to each other. This study shows the effectiveness of Lamb wave time reversal for temporal recompression of dispersive Lamb waves for damage detection in health monitoring applications.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Lamb Waves; Time Reversal Acoustics; Health Monitoring; Wavelet Transform
ID Code:99097
Deposited On:05 Sep 2015 08:36
Last Modified:05 Sep 2015 08:36

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