Ventilated acoustic metamaterial window panels for simultaneous noise shielding and air circulation

Abstract

The conflict between the acoustical performance and ventilation efficiency in conventional noise barriers limits their application potentials in several settings. To address this challenge, we design and experimentally demonstrate a ventilated tunable acoustic metamaterial for noise mitigation at targeted frequencies. Through the structure, a peak normal incidence sound absorption coefficient of more than 0.96 at 1000 Hz and the peak normal incidence sound transmission loss of 18 dB is achieved while maintaining the air circulation with a 45% open area of ventilation. Such a high absorption near the resonant frequency under the ventilation condition originates from high impedance matching between the metastructure and air. Next, we present a proof-of-concept for the fabrication of acoustic metapanels for large scale applications. A simple jigsaw puzzle-like assembly technique is used to interconnect the multiple unit cells, leading to the production of integrated metapanels. The experimental findings validate the potential applications of the proposed metapanels for low-to-mid frequency noise control in a small ventilated spaces.