Transient sound radiation from a clamped circular plate with viscoelastic layers

Abstract

In this article, the transient sound radiation from a clamped circular plate with a viscoelastic layer excited by impact is studied analytically and experimentally. The composite plate vibrations are obtained by using the normal mode analysis and the eigenvalues are obtained by a Mindlin plate theory, including the rotary inertia and shear deformation. In impact, the contact force developed between the ball and the plate with attached layers is obtained by Hertz contact theory. The radiated sound pressure in the farfield is calculated by the Rayleigh integral. Prediction of the waveforms of sound radiating from the plate with attached layers and a method for reducing noise generation from the plate by impact force are also shown in this article. The analytical results can be applicable to multilayered plate and noncentral impacted cases. Using the results of this article, the thickness of an attached viscoelastic layer to reduce the noise to the desired level can be decided.