Guided waves in elastic plates with Gaussian section variation: Experimental and numerical results
P. Marical (a), M. Ech-Cherif El-Kettani (a), M.V. Predoi (b)
(a) Laboratoire d’Acoustique, Ultrasonore et d’Electronique (LAUE), UMR CNRS 6068, Universite´ du Havre, Place Robert Schuman,
BP 4006, 76610 Le Havre, France
(b) University Politechnica of Bucharest, Department of Mechanics, Bucharest, Romania
Received 9 October 2006; received in revised form 13 April 2007; accepted 5 May 2007
Available online 9 June 2007
Abstract
Experimental and numerical results are presented on the behavior of guided waves in elastic plates in plane strain that include a Gaussian variation of their section, located between two areas of constant thickness. The area of varying section is wide compared to the used wavelengths, which allows wave propagation inside this area. The experimental results show that an incident Lamb wave is indeed converted into an adiabatic wave inside the varying section domain. A trapped wave in the Gaussian domain is also observed, depending on the incident mode and on the Gaussian maximum height. Outside the varying section domain, conversion into different Lamb waves is observed. This conversion phenomenon is experimentally quantified by the measurement of the Lamb wave normal displacement and of its carried energy. A numerical study, based on the Finite Elements Method is performed, and successfully compared to the experimental results.
2007 Elsevier B.V. All rights reserved. PACS: 43.20.Mv
Keywords: Waveguide of varying section; Lamb waves; Adiabatic waves; Conversion