音響メタマテリアルによる音波の反射制御に関する研究

抄録

Acoustic metamaterials are artificial materials whose acoustic properties, such as the medium density and volume elasticity, are adjusted in order to reproduce a peculiar wave phenomenon. The materials are featured by a miniature unit structure whose size is usually smaller than the wavelength. In the present study, we developed a sound reflection device comprising an acoustic metamaterial used to reflect the incoming acoustic waves back to an arbitrary direction in space. The metamaterial structure is composed of a series of acoustic ducts where each set of neighboring paths has a constant relative length. Numerical simulations revealed that the incident sound wave reflected for the target reflection angle as large as 60 degrees. In addition, the sound field measurements showed that reflection of sound whose frequency ranged between 500 Hz to 2kHz could be possible.