Time-frequency representation of Lamb waves using the reassigned spectrogram
- 23 March 2000
- journal article
- Published by Acoustical Society of America (ASA) in The Journal of the Acoustical Society of America
- Vol. 107 (5), L19-L24
- https://doi.org/10.1121/1.428894
Abstract
©2000 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America. The following article appeared in Acoustics Research Letters Online, 107:L19-L24, 2000 and may be found at http://dx.doi.org/10.1121/1.428894DOI: 10.1121/1.428894This brief note reports on a study that applies the reassigned spectrogram (the reassigned energy density spectrum of the short-time Fourier transform [STFT]) to develop the dispersion curves for multimode Lamb waves propagating in an aluminum plate. The proposed procedure first uses the spectrogram to operate on a single, laser-generated and detected waveform to develop the dispersion relationship for this plate. Next, a reassignment procedure is used to refine the time-frequency resolution of the calculated dispersion curves. This reassignment operation clarifies the definition of the measured modes. This study demonstrates that the reassigned spectrogram is capable of distinguishing multiple, closely spaced Lamb modes in the ultrasonic frequency range. ©2000 Acoustical Society of AmericaKeywords
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