The amplitude of the fundamental S0 mode of Lamb waves can be used in testing for delaminations in laminate plates [1]. By scanning over the surface beneath which a delamination lies, it is possible to measure the size and depth of the delamination based on the variation in the amplitude of the of Lamb wave signals. The variation in amplitude is strongly dependent upon the depth of the delamination, and is most sensitive to delamination near to the surface of the laminate. This technique is comparable to the delayed pulse echo technique, and can be used to complement other techniques [2]. Numerical analysis using a finite element package is used to complement experimental observations. It was found to agree with experimental observations.
REFERENCES
K. S. Tan, N. Guo, B. S. Wong and C. G. Tui, "Experimental evaluation of delaminations in composite plates by the use of Lamb waves", Composites Science and Technology, Vol. 53, No. 1, pp. 77-84, 1995
K. S. Tan, N. Guo, B. S. Wong and C. G. Tui, "Comparison of Lamb waves and pulse echo in detection of near-surface defects in laminate plates", NDT & E International, Vol. 28, No. 4, pp. 215-223, 1995
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 4, pages 2291 - 2294 Publisher:Ashgate Publishing Company
NDTnet
