Vibro-acoustic mitigation in composite structures using viscoelastic damping and soundproofing poroelastic technologies

Abstract

This paper presents a numerical approach to study the vibro-acoustic behavior of composite structures immersed in a surrounding fluid medium. Such approach consists on the development of a coupled mitigation strategy aiming either vibration suppression or acoustic attenuation. To this end, viscoelastic damping technologies are applied to the composite host structure in a standard integrated layer damping configuration whereas surface mounted poroelastic materials are included to perform the design of the damped and quieter composite structure. A finite element model is developed to model multi-layered structures which is based on the layerwise kinematic assumptions. On the other hand, poroelastic treatments are developed based on the Biot theory of poroelasticity. As a result, using the capabilities of the multi-layered model developed, different vibro-acoustic indicators are analyzed, namely, the mean square velocity and the radiation efficiency of the composite host plate, the transmission loss of the fluid-plate system and the radiated sound power. In addition, a study addressing the physical coupling between both solid and fluid phases of the poroelastic material is performed in order to realise the consequences in terms of the sound mitigation performance of the poroelastic treatment owing to the variability in the distributed stiffness of the host composite plate imposed by different fibers orientation.