ONR NURP: Acoustic Metamaterials for Undersea Applications

ONR NURP: Acoustic Metamaterials for Undersea ApplicationsAbstract:The primary focus of the proposed project is the training of a PhD student in technologies relevant to future Naval undersea warfare applications via the Naval Undersea Research Program (NURP)'. To this end, the PhD student will spend three summers at the NavalUndersea Warfare Center (NUWC), Newport, RI working with NUWC s'cientists in the area of acoustic metamaterials. The main focus of the technical work proposed in this project is the development of' thin, lightweight, highly acoustically absorptivemetamaterials for naval applications. We propose to design metamaterials using mo''deling techniques and genetic design, construct prototype materials using multi-material additive manufacturing and test the perform''ance of the materials using acoustic holographicmethods, impedance tube measurements, and echo-chamber transmission loss measuremen''ts. Lastly, we will investigate methods for dynamically adapting theabsorption of the material as a function of frequency for both' in-air and in-water applications. The goal of the work to be performed under the NURP program is to rescale in-air designs to underwater and to test the response of these materials for either vibrationor acoustic absorption in the underwater environment.