M. Castro-Colínª, J.A. Lópezb and R. Oseguedac
ª Physics Department, U.T. El Paso, El Paso, TX79968.
b Physics Department, U.T. El Paso, El Paso, TX 79968.
c FAST Center, Burgess Hall, U.T. El Paso, El Paso, TX 79968.
Recibido el 2 de marzo de 2006
Aceptado el 18 de agosto de 2006
Abstract
We studied experimentally the ultrasonic propagating modes produced by a laser pulse of 532 nm while impinging on an aluminum plate. The beam, shaped as a line, induced various Lamb modes whose relative power varied with the laser line length. Identification of their mode was performed by detecting the ultrasonic modes with piezoelectric detectors along a propagation direction orthogonal to the line, and using two dimensional fast Fourier transform. Good agreement is observed between theoretical and experimental dispersion curves for the first fundamental symmetric and anti-symmetric modes. Results are shown for 12 and 24 mm laser line-length at 13.6 and 16.8 ns pulse-width.
Keywords: Laser based ultrasound; non-destructive testing; photoacoustic.
Resumen
Se presenta el estudio experimental de los modos ultrasónicos de propagación producidos por el impacto de un pulso laser de 532 nm en una placa de aluminio. El haz, con forma de una línea, induce varios modos de Lamb cuya potencia relativa varía con la longitud de la línea del láser. La identificación del modo correspondiente se realizó detectando los modos ultrasónicos con detectores piezoeléctricos a lo largo de la dirección ortogonal a la propagación de la línea y utilizando una transformada de Fourier en dos dimensiones. Buen acuerdo se obtiene entre las predicciones teóricas y las curvas de dispersión medidas experimentalmente para los primeros modos fundamentales simétrico y antisimétrico. Los resultados se muestran para longitudes de línea de 12 y 24 mm a 13.6 y 16.8 ns de anchura de pulso.
Descriptores: Ultrasonido originado con láser; pruebas no destructivas; fotoacústica.
PACS: 42.62.Cf; 81.70.Cv; 43.35.Zc; 43.35.Ud
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Acknowledgements
This work was partially supported by the National Science Foundation under grant PHYS-1996, and FAST under grant number F4962-95-1-0518, Air Force Office of Scientific Research, Air Force Materiel Command, USAF. We acknowledge constructive discussions with E. Rodriguez and S. Nazarian.
References
1. W.J. Percival and E.A. Birt, J. Acoust. Soc. Am. 100 (1996) 3070. [ Links ]
2. I. A. Viktorov, Rayleigh and Lamb waves (Ed. Plenum Press, New York 1967). [ Links ]
3. R.D. Costley Jr. and Y.H. Berthelot, Ultrasonics 32 (1984) 249. [ Links ]
4. R.C. Addison and A.D.W. MacKie, 1994 Ultrasonics Symposium IEEE (1994) 1201. [ Links ]
5. D.N. Alleyne and P. Cawley, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 39 (1992) 381. [ Links ]
6. R.D. Costley Jr., Y.H. Berthelot, and L.J. Jacobs, J. Nondestr. Test. 13 (1994) 33. [ Links ]
7. B. Mi and I.C. Ume, J. Nondestr. Test. 21 (2002) 23. [ Links ]
8. M.D.G. Potter and S. Dixon, Nondestr. Test. and Eval. 20 (2005) 201. [ Links ]
9. E. Dieulesaint and D. Roger, Elastic waves in solids: applications to signal processing (Ed. John Wiley and Sons, New York 1980). [ Links ]
10. C.B. Scruby et al. Laser ultrasonics: techniques and applications (Ed. Adam Hilger, Bristol, Philadelphia and New York 1990). [ Links ]
11. W. Sachse and Y-H Pao, J. Appl. Phys. 49 (1978) 4320. [ Links ]
12. J.W. Cooley and J.W. Tukey, Math. Comput. 19 (1965) 297. [ Links ]
13. H. Guo, G.A. Sitton, and C.S. Burrus, Proc. IEEE Conf. Acoust. Speech and Sig Processing (ICASSP) 3 (1994) 445. [ Links ] ]]>