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Experimental Mechanics

, Volume 41, Issue 4, pp 332–342 | Cite as

Spectrotemporal analysis of guided-wave pulse-echo signals: Part 2. Numerical and experimental investigations

  • S. -C. Wooh
  • K. Veroy
Article

Abstract

Part 2 of this paper seeks the numerical and experimental procedures for implementing the Morlet wavelet transform for the spectrotemporal analysis of multimode dispersive waves. The sensitivity due to the spectral parameters α and ω0, defining the bandwidth and center frequency of the mother wavelet, is studied through an error analysis of the simulation signals. The algorithm for determining the group delays is extended to multimode signals by introducing a thresholding technique. The ultimate goal of this study is to nondestructively detect and locate discontinuities in a thin plate. This is demonstrated by experimentally measuring the travel distance of a Lamb wave from a single waveform.

Key Words

Guided waves multimode dispersion wavelet transform group delays thresholding bandwidth 

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References

  1. 1.
    Wooh, S.C. andVeroy, K., “Spectrotemporal Analysis of Guided-wave Pulse-echo Signals: Part 1. Dispersive Systems,” EXPERIMENTAL MECHANICS,41,324–331 (2001).Google Scholar
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    Misiti, M., Misiti, Y., Oppenheim, G., andPoggi, J.M., Wavelet Tool-box: For Use with Matlab, Mathworks Inc., Natick, MA (1996–1997).Google Scholar
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    Pierce, S.G., Culshaw, B., Philip, W.R., Lecuyer, F., andFarlow, R., “Broadband Lamb Wave Measurements in Aluminum and Carbon Glass Fibre Reinforced Composite Materials Using Non-contacting Laser Generation and Detection,”Ultrasonics,35,105–114 (1997).Google Scholar
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    Klein, M.B. and Bacher, G.D., “High-sensitivity Laser-based Detection of Lamb Waves Using Photo-EMF Sensor,” Proceedings of the ASNT Spring Meeting (Mar. 1998).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 2001

Authors and Affiliations

  • S. -C. Wooh
    • 1
  • K. Veroy
    • 1
  1. 1.Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridge

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