The project explores cloaking of sound and vibration. A cloak surrounds an object so that it causes waves of sound or vibration to bypass the object. Cloaking appeared on the scene in 2006 with the first demonstration of a device that can cloak electromagnetic microwaves. Acoustic cloaking is in its infancy, and it is not even clear whether cloaking of elastic waves is possible. This project will address these questions through theory and simulation. The first goal is a thorough understanding of acoustic cloaks, focusing on so-called pentamode metamaterials. These are easily sheared, like rubber or water, but have the unusual property that they support a biaxial state of stress, as compared with hydrostatic. The main objective, elastodynamic cloaking, will first consider a metamaterial layer capable of emulating the wave properties of a thicker layer of normal solid. Mathematical relations involving coordinate and gauge transformations will be used, and more complicated cylindrical and spherical structures will be studied. The final goal is a realistic model of Rayleigh wave cloaking. Longer term societal benefits will be enhanced technology for reducing vibration and noise, and methods to channel destructive mechanical wave energy around sensitive areas and objects, such as shielding buildings from earthquake ground motion. The project will include a seminar for honors engineering freshmen on the subject of metamaterials, cloaking, and futuristic technology. Undergraduates will be explicitly involved in the research, building on a current project for seniors. A web-page explaining cloaking in layperson terms will be enhanced.
|Effective start/end date||8/1/09 → 7/31/12|
- National Science Foundation (National Science Foundation (NSF))