A coherent method for the measurement of the dispersive curves of elastic waveguides
| Autor: | Hailan Zhang, Shuwu Dai, Chengyu Zhang |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | The Journal of the Acoustical Society of America. 109:2438-2438 |
| ISSN: | 0001-4966 |
| DOI: | 10.1121/1.4744635 |
| Popis: | A coherent technique is presented to measure the dispersive curves of elastic waveguides. Waveforms received at several positions along the propagation path are transformed into the frequency domain by FFT. The phase thus obtained has been truncated into the range of the principle value. The true phase difference between the nearest and the farthest waveforms is restored from the truncated phases by summing all phase differences between the contiguous waveforms which are picked up at the positions close enough that the phase differences between contiguous waveforms are less than 4. The restored phase is then used to calculate the phase velocity at different frequencies. The use of the phase information makes the measurement more precise and stable than traditional noncoherent methods. The method is applied to measure the dispersive curves of an aluminum plate with rough surfaces and the result is compared with that of the smooth plate. It is found that the effect of the roughness is the attenuation of the... |
| Databáze: | OpenAIRE |
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