Modal models for vibro-acoustic response analysis of fluid-loaded plates

Abstract

Modal models are developed for vibro-acoustic response computation of fluid-structure interaction problems on the basis of modal frequencies and modal damping ratios. The uncoupled equations are built using in vacuo mode shapes and fluid-loaded undamped real mode shapes and are solved for the coupled response of the fluid-loaded structures. Conventional modal analysis techniques are used to obtain the response of the coupled fluid-structure systems from a reduced-order modal model. The accuracy and efficiency of the technique is demonstrated with examples of computing the vibro-acoustic response of a baffled thin plate and a baffled thick stiffened plate. The comparisons in terms of mean-square normal velocity and sound power between the present models and the conventional coupling method show a good agreement. The present modal models for computing the vibro-acoustic response of the fluid-loaded structures have the advantages of constructing a model from modal parameters that could be obtained from either numerical computation or experimental measurement; a small dimension of using only a very small number of modes; and of being applicable to conventional modal analysis techniques. These features may make the present technique a powerful tool for dynamics and the control of fluid-loaded structures.