Numerical predictions and experiments on the free-plate edge mode

Numerical predictions and experiments on the free-plate edge mode

Emmanuel Le Clezio (a), Mihai Valentin Predoi (b), Michel Castaings (a), Bernard Hosten (a), Martine Rousseau (c)

a) Laboratoire de Mecanique Physique, Universite Bordeaux 1, UMR CNRS 5469351, Cours de la Liberation, 33405 Talence Cedex, France

b) Department of Mechanics, University Politechnica of Bucharest, Splaiul Independentei 313, BN035, Sector 6, Bucharest, Romania

c) Laboratoire de Modelisation en Mecanique, Universite Paris 6, UMR CNRS 7607, 4 place Jussieu, Tour 66, case 162 75252 Paris Cedex 05, France

Received 18 June 2002; accepted 20 June 2002

Abstract

In this paper, the edge mode vibration is studied with three different methods: the reciprocal work method, already used by Torvik [J. Acoust. Soc. Am. 41 (1967) 346] to model this phenomenon, the S-parameter method and a finite element model that are

applied for the first time to the study of the edge resonance. Moreover, laser probe measurements of the edge mode have also been

performed and compared to the numerical predictions. The good agreement between the numerical predictions and the experimental

data allows full understanding of the resonant phenomenon. The edge resonance is linked to the strong increase in amplitude of two

complex Lamb waves, and the edge mode is proved to radiate into the plate as the first symmetrical Lamb mode S0. Displacements

at the edge and away from the edge have been computed and measured to evaluate the spatial and temporal behaviour of the edge

mode. The dependence of the edge resonance frequency and amplitude on the Poisson coefficient has also been studied.

PACS:

43.35. Ac; 43.35.Ae

Keywords:

Ultrasound; Edge mode; Lamb waves

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Ultrasonics 41, pp. 25 -40, 2003