Research on Elastic Scattered Wave of Submerged Elastic Plate

Abstract:

It is proved by theory and experiment that the arrival time of elastic scattering wave is determined by group velocity of Lamb wave in plate and the speed of elastic scattering wave in water. The frequency dispersion equation of Lamb wave is derived for submerged elastic plate, and the phase velocity and group velocity dispersion curves are obtained by numerical calculation method. It is found that the phase velocity is greater or less than the group velocity at different frequency-thickness products. The energy propagation speed of wave is group velocity, so the arrival time of elastic scattering wave is determined by group velocity of Lamb wave in plate and the speed of sound in water. Experimental results show that elastic scattering wave is ahead of or behind the edge wave in echoes of elastic steel plate. The experiment results confirm validity of the theoretical analysis results.

• Periodical: Applied Mechanics and Materials (Volumes 303-306)
• Pages: 2779-2783
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.303-306.2779
• Online since: February 2013
• Authors: Wen Jian Chen, Hui Sun, Tie Lin Sun
• Keywords: Elastic Scattering, Group Velocity, Lamb Wave, Phase Velocity

References

[1] F. Simonetti, Lamb wave propagation in elastic plates coated with viscoelastic materials, J. Acoust. Soc. Am., Vol. 115, no. 5(2004), p.2041-(2053).

DOI: 10.1121/1.1695011

[2] C. Pachiu, New analytical method of dispersion curves in plane layered structures, Journal of Computational Acoustics, Vol. 20, no. 3(2012), pp.1-19.

DOI: 10.1142/s0218396x12500105

[3] Yung-Chun LEE. Measurements of multimode leaky Lamb waves propagating in metal sheets, Jpn. J. Appl. Phys., Vol. 10, no. 1(2001), pp.359-363.

DOI: 10.1143/jjap.40.359

[4] Kohji Toda and Kenji Motegi. Coupling of velocity dispersion curves of leaky Lamb waves on a fluid-loaded plate, J. Acoust. Soc. Am., Vol. 107, no. 2(2000), pp.1045-1048.

DOI: 10.1121/1.428285

[5] Sun Hui, Tang Weilin, Cao Hui, Analysis of echoes from a finite elastic cylindrical shell in water, In Proceeding(s) of the 3rd European conference on underwater acoustics(1996), pp.139-143.

[6] Z. Zhu，J. Wu. The propagation of Lamb waves in a plate bordered with a viscous fluid, J. Acoust. Soc. Am., Vol. 98, no. 2(1995), pp.1057-1064.

[7] Gong Jiayuan, Study on Leaky Lamb Waves Propagation in Elastic Plates and Cylindrical Shells Coated with a Viscoelastic Damping Material in Water, M. Eng thesis of Harbin engineering University, (2011).

[8] X. Luís Deán-Ben, Cristina Trillo, Ángel F. Doval, Phase and group velocity measurement of ultrasonic guided wavetrains in plates by pulsed TV holography, J. Acoust. Soc. Am, Vol. 127, no. 4(2010), pp.2210-2219.

DOI: 10.1121/1.3327795

[9] Brian T. Hefner, Philip L. Marston, Backscattering enhancements associated with the excitation of symmetric Lamb waves on a circular plate: direct and holographic observation, J. Acoust. Soc. Am, Vol. 2(2001), no. 1, pp.55-60.

DOI: 10.1121/1.1353396

[10] Brian T. Hefner, Philip L. Marston, Backscattering enhancements associated with antisymmetric Lamb waves confined to the edge of a circular plate: Direct and holographic observations, J. Acoust. Soc. Am, Vol. 3, no. 3(2002), pp.101-106.

DOI: 10.1121/1.1480895