Acoustic Mitigation System For Horizontal, Planar Surfaces Onboard Naval Ships

Typical acoustic materials rely on embedded continuous mass layer to attenuate low frequency sound. Energy from low frequency sound is not effectively mitigated with these materials unless a substantial amount of mass is added. Thus, standard materials for low frequency noise control tend to be heavy, expensive and difficult to install. A new technology is being developed that utilizes optimized combinations of layers of acoustic materials and embedded masses to reduce noise and vibration specifically in the low frequency range of 60 to 200Hz. The technology permits attenuation of low frequency sound without significantly increasing mass and can be demonstrated to reduce both airborne and structure-borne noise and vibration. Although the technology has been successfully demonstrated for thinner panels such as in buildings and mechanical equipment, additional research and development is required to optimize the technology to the particular structures and acoustic signatures onboard Naval ships. The proposed work will investigate the design of the composite material for Naval applications. Two different material systems will be constructed and tested on a structure representative of selected onboard applications.