Scattering Phenomena of Edge Guided Waves at and around Notches

Abstract:

This work presents a computational investigation into the scattering of edge guided waves travelling by a notch. To establish a good understanding of this scattering phenomenon, the analysis was conductedon a range of length scales. The finite element analysis indicate that the edge guided surface waves are scattered by the presence of a notch which resulted in a SH₀-like appearance wave radiating into the medium. This can be mistaken as a mode conversion of the fundamental lamb modes or even a source at notch tips. The phenomenon becomes harder to notice at higher frequency as increasing the frequency decreases the speed and both the bulk and surface waves travel at identical speeds. A clear understanding of this interaction furthers our knowledge in one of the most prominent interaction in the study of acoustic waves for structural health monitoring.

• Periodical: Advanced Materials Research (Volumes 891-892)
• Pages: 1249-1254
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.891-892.1249
• Online since: March 2014
• Authors: Nithurshan Nadarajah*, Benjamin Steven Vien, Wing Kong Chiu, L.R. Francis Rose
• Keywords: Edge Waves, Lamb Waves, Nondestructive Testing (NDT), Wave Scattering

References

[1] C. Ramadas, J. Padiyar, K. Balasubramaniam, M. Joshi and C. V. Krishnamurthy, Lamb wave based ultrasonic imaging of interface delamination in a composite t-joint, NDT &E International 44 (2011) 523-530.

DOI: 10.1016/j.ndteint.2011.05.009

[2] S. Yashiro, J. Takatsubo and N. Toyama, An ndt technique for composite structures using visualized lamb-wave propagation, Composites Science and Technology 67 (2007) 3202-3208.

DOI: 10.1016/j.compscitech.2007.04.006

[3] H. Sohn, D. Dutta, J. Y. Yang, H. J. Park, M. DeSimio, S. Olson and E. Swenson, Delamination detection in composites through guided wave field image processing, Composites Science and Technology 71 (2011) 1250-1256.

DOI: 10.1016/j.compscitech.2011.04.011

[4] W. J. Staszewski, B. C. Lee and R. Traynor, Structural damage detection using lamb waves and 3-d laser vibrometry, Destech Publications Inc, Lancaster, (2008).

[5] D. Alleyne and P. Cawley, A 2-dimensional fourier-transform method for the measurement of propagating multimode signals, Journal of the Acoustical Society of America 89 (1991) 1159-1168.

DOI: 10.1121/1.400530

[6] D. N. Alleyne and P. Cawley, Optimization of lamb wave inspection techniques, NDT & E International 25 (1992) 11-22.

DOI: 10.1016/0963-8695(92)90003-y

[7] P. B. Nagy, M. Blodgett and M. Golis, Weep hole inspection by circumferential creeping waves, NDT & E International 27 (1994) 131-142.

DOI: 10.1016/0963-8695(94)90604-1

[8] C. Doherty and W. K. Chiu, Scattering of ultrasonic-guided waves for health monitoring of fuel weep holes, Structural Health Monitoring-an International Journal 11 (2012) 27-42.

DOI: 10.1177/1475921710395814

[9] C. Doherty and W. K. Chiu, Guided wave mode selection for health monitoring of sub-surface hidden defects on fuel weep holes, Journal of the Acoustical Society of America 133 (2013) 3863-3874.

DOI: 10.1121/1.4803520

[10] K. F. Graff, Wave motion in elastic solids, Chap. 6, Dover, New York, (1975).

[11] J. D. Achenbach, Wave propagation in elastic solids, Chap. 5, Elsevier, Amsterdam, (1973).

[12] M. J. S. Lowe and O. Diligent, Low-frequency reflection characteristics of the s(0) lamb wave from a rectangular notch in a plate, Journal of the Acoustical Society of America 111 (2002) 64-74.

DOI: 10.1121/1.1424866

[13] D. P. Hurst and J. A. G. Temple, Calculation of the velocity of creeping waves and their application to non-destructive testing, International Journal of Pressure Vessels and Piping 10 (1982), no. 6, 451-464.

DOI: 10.1016/0308-0161(82)90005-9