19th Asia-Pacific Vibration Conference (APVC2021)

Noise and vibration control have been realized by using phononic crystals and acoustic metamaterials. However, these methods have been always suffering from some fundamental limitations including narrow working bandwidth and large volume. How to realize broadband noise and vibration control in a small footprint has been a challenge. Recently, as a booming branch of metamaterials, a new kind of artificial structure named metasurface has provided feasible solutions. As a 2D mapping of metamaterial, metasurface has enabled extraordinary wavefront manipulation with compact and lightweight structure of sub-wavelength scale. In this work, we have proposed a generic framework for omnidirectional elastic-wave isolation based on a single layer of ultrathin elastic metasurface. An enclosure enveloped by the proposed metasurface can behave like a “cage”, preventing elastic waves generated by the outside or inside sources from entering into or escaping out of the shielding region. Numerical and experimental results coincidentally demonstrate that an arbitrary-shape shielding area surrounded by metasurfaces can be constructed, which is capable of isolating elastic waves from all directions. Our ultrathin metasurface design can achieve efficient elastic-wave manipulation and isolation with robust performance for arbitrary “cage” shape. The present work extends the strategy for noise and vibration control in elastodynamics and acoustics.

Elastic-wave; Metasurface; Omnidirectional; Isolation; Vibration