Specular and diffuse reflections of rays in coupled thin plates at high frequencies

Alain Le Bot (1) , Vincent Cotoni (2)

1 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes
2 GAUS - Groupe d'Acoustique de l'Université de Sherbrooke

The flexural energy distribution in two right-angled point-excited thin plates at high frequencies is investigated by means of an integral energy flow approach. Time and frequency-averaged energy fields are described by the superposition of uncorrelated cylindrical waves stemming from both boundaries and direct sources. Specular and diffuse laws are considered for the reflection and transmission of rays, giving rise to two kinds of energy equations. The diffuse law leads to a Fredholm integral equation while the specular law is shown to allow an image source solution when the plates have identical propagation properties. The algorithm for computing the image position, magnitude and directivities is described. Then, some comparisons between the results from the two energy formulations and also from the Statistical Energy Analysis and the numerical solving of the equations of motion are performed with a couple of damped plates at high frequency. The non diffuse pattern of the averaged flexural energy fields is well described by the energy flow approaches.

Mots clés: Vibration; Rays; Plate; Energy flow; Statistical Energy Analysis

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Alain Le Bot, Vincent Cotoni. Specular and diffuse reflections of rays in coupled thin plates at high frequencies. Journal of Sound and Vibration, 2003, 265 (1), pp.23-41. ⟨hal-00469441⟩