In this work, we present our study of Lamb wave crack detection using wavenumber analysis. The aim is to demonstrate the application of wavenumber analysis to 3D Lamb wave data to enable damage detection. The 3D wavefields (including v_x, v_y and v_z components) in time-space domain contain a wealth of information regarding the propagating waves in a damaged plate. For crack detection, three wavenumber analysis techniques are used: (i) time-space Fourier transform which can transform the time-space wavefield into frequency-wavenumber representation while losing the spatial information; (ii) short space Fourier transform which can obtain the frequency-wavenumber spectra at various spatial locations, resulting in a space-frequency-wavenumber representation; (iii) local wavenumber analysis which can provide the distribution of the effective wavenumbers at different locations. All of these concepts are demonstrated through a numerical simulation example of an aluminum plate with a crack. The 3D elastodynamic finite integration technique (EFIT) was used to obtain the 3D wavefields, of which the v_z (out-of-plane) wave component is compared with the experimental measurement obtained from a scanning laser Doppler vibrometer (SLDV) for verification purpose. The experimental and simulated results are found to be in close agreement. The application of wavenumber analysis on 3D EFIT simulation data shows the effectiveness of the analysis for crack detection.

Date Published: 17 April 2013
PDF: 13 pages
Proc. SPIE 8695, Health Monitoring of Structural and Biological Systems 2013, 86952Z (17 April 2013); doi: 10.1117/12.2012249

Published in SPIE Proceedings Vol. 8695:
Health Monitoring of Structural and Biological Systems 2013
Tribikram Kundu, Editor(s)