Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
권호 표지

Laser Generation of Focused Lamb Waves

  • Jhang, Kyung-Young (School of Mechanical Engineering, Hanyang University) ;
  • Kim, Hong-Joon (School of Mechanical Engineering, Hanyang University) ;
  • Kim, Hyun-Mook (School of Mechanical Engineering, Hanyang University) ;
  • Ha, Job (School of Mechanical Engineering, Hanyang University)
  • Published : 2002.12.30
Download PDF
⟨ Previous Next ⟩

Abstract

An arc-shaped line array slit has been used for the laser generation of focused Lamb waves. The spatially expanded Nd:YAG pulse laser was illuminated through the arc-shaped line array slit on the surface of a sample plate to generate the Lamb waves of the same pattern as the slit. Then the generated Lamb waves were focused at the focal point of which distance from the slit position is dependent on the curvature of slit arc. The proposed method showed better spatial resolution than the conventional linear array slit in the detection of laser machined linear defect and drill machined circular defect on aluminum plates of 2mm thickness. Using the focused waves, we could detect the linear defect and the circular defect with the improvement of spatial resolution. The method can also be combined with the scanning mechanism to get an image just like by the scanning acoustic microscope(SAM).

Keywords

References

  1. Alleyne, D. N. and Cawley, P. (1992) The interaction of lamb waves with defects, IEEE Trans. Ultrason. Ferroelectr. Freq. Control., Vol. 39, No. 3, pp. 381-397
  2. Bork, U. and Challis, R. E. (1995) Nondestructive evaluation of the adhesive fillet size in a t-peel joint using ultrasonic lamb waves and a linear-network for data discrimination, Meas. Sci. Technol., Vol. 6, No.1, pp. 72-84
  3. Cerniglia, D., Jhang, K. Y. and Djordjevic, B. B. (2000) Non-Contact Ultrasonic testing of Aircraft Lap Joint, Proceedings of 15th World Conference on Non-Destructive Testing, edited by G. Nardoni et al., Italian Society for NDE, 161st in CD title
  4. Dewhurst, R. J. Noui, I. and Shan, Q. (1990) Polymer film thickness measurement using laser-ultrasound techniques, Rev. Sci. Instrum., Vol. 61, No.6, pp. 1736-1742
  5. Guo, N. and Cawley., P. (1994) Lamb reflection for the quick non-destructive evaluation of large composite laminates, Mater. Eval. Vol. 52, No.3, pp. 404-411
  6. Hite, R. M. (1963) Generation of transient elastic waves by transient surface heating, J. Appl. Phys., Vol. 34, No. 12, pp. 3559-3567
  7. Karautkramer, J. and Karautkramer, H. (1977) Ultrasonic testing of materials, Springer Verlag, 1977, 2nd edn, Chapter 22, pp. 399-426
  8. Jhang, K. Y., Kim, H. J., Ceringlia, D. and Djordjevic, B. (2001) Non-Contact Ultrasonic Testing of Aircraft Joints Using Laser Generated Lamb Wave, Journal of the Korean Society for Nondestructive Testing, Vol. 21, No.2, pp. 163-168 (written in Korean)
  9. Jhang, K. Y., Kim, K. J., Kim, H. J. and Ha, J. (2002) Generation of the Focused Type Laser-Ultrasonic Wave, Review of Progress in Quantitative NDE, Abstract p. 60 (proceedings to be published)
  10. Pierce, R, Ume, C. and Jarzynski, J. (1995) Temporal Generation of a laser source for the generation of ultrasonic waves, Ultrasonics, Vol. 33, No.2, pp. 133-137
  11. Pierce, S. G., Staszevski, W. J., Gachagan, A., James, I. R, Philip, W. R, Worden, K., Culshaw, B., Mcnab, A., Tomlinson, G. Rand Hayard, G. (1997) Ultrasonic condition monitoring of composite structures using a low profile acoustic source and an embedded optical fibre sensor, Proc. SPIE Int. Opt. Eng., Vol. 30 No.4, pp. 437-448
  12. Rogers, W. P. (1995) Elastic property measurement using Rayleigh Lamb waves, Res. Nondestru. Eval., Vol. 6, pp. 185-208
  13. Scruby, C. B. and Drain, L. E. (1990) Laser ultrasonics: technique and applications Adam Hilger, Chapter 5, pp. 223-324
  14. Vikotorov, I. A. (1967) Rayleigh and Lamb waves physical theory and applications, Plenum Press, New York, Chapter 2, pp. 67-121