The effect of a local stiffener in the structural—acoustic coupled system

Abstract This article proposes an analytical method that can be used to obtain the vibro-acoustic modal and forced response characteristics of a three-dimensional structural—acoustic coupled system, where the coupled system is composed of an acoustic cavity with a rectangular plate that is stiffened by a local stiffener. Through the proposed method, the effect of the local stiffener on the natural frequencies, modes, and forced responses is identified for the plate—cavity coupled system with the local stiffener. The relationship between the thickness and the location of the local stiffener on the vibro-acoustic modal characteristics and forced responses is investigated through the structural—acoustic modal coupling coefficient. The high peak-noise due to the strong modal coupling between the plate and acoustic modes can be effectively reduced by properly designing the local stiffener in the coupled system. Finally, the modal characteristics and frequency responses obtained by the proposed method are compared with those of finite-element analysis. The results of this article provide useful information for suppressing the booming noise generated by the strong modal coupling between the plate and acoustic modes in the coupled system.

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