Sound Transmission Tuned by Active Feedback Control Attached to Elastic Wave Metamaterials Immersed in Water.

Elastic wave metamaterials have been widely exploited with their dynamic superior properties and outstanding acoustic responses. However, it is difficult to directly manipulate sound pressure in low frequencies. In this study, we propose a new kind of elastic wave metamaterial which consists of vertical and lateral resonators as well as orthogonal stiffeners. The active feedback control system is applied to extend to the tunable scope for both lower and higher frequency regions and change the characteristics of acoustic-structure coupling. Its effective mass density is also discussed with different feedback constants. In order to present effects of the fluid-solid interaction, we considered that the elastic wave metamaterial is immersed in different fluid medium and its sound transmission loss (STL) is calculated. This work provides a feasible method for creating mechanical/acoustic models with multi-functional potentials. [ABSTRACT FROM AUTHOR]