Reconfigurable metatiles with circular maze-like space-coiling-based acoustic metastructure for low-to-mid frequency sound attenuation

Abstract

This study presents a compact, lightweight, and reconfigurable acoustic metatile for sound mitigation applications. The metatile prototype is designed based on a circular maze-like acoustic metastructure, which utilizes a space-coiling technique for enhanced acoustic performance in low-to-mid frequencies. The proposed labyrinthine acoustic metadisk structure comprises a central hollow front face sheet and two coiling-up backing cavities. Experimental results show that the metadisk has high absorption peaks of 0.81 and 0.75 at 574 and 1436 Hz, respectively, and exhibits high sound transmission loss (STL) values ( ≥25 dB) in separate wide frequency bands between 100–580 Hz and 820–1600 Hz. Based on the metadisk samples, metatiles are constructed, which are 30.5 × 30.5 cm 2 in size. The acoustic performance of these metatiles is investigated in two distinct scenarios. Two prototypes of the acoustic metatile are presented: the metacage and the metapanel. The metacage is a cubical box-shaped structure constructed using five metatiles, which showed a wideband insertion loss of ≥10 dB in 200–16 000 Hz and ≥20 dB over 400–5000 Hz. On the other hand, the metapanel is constructed using nine metatiles, which exhibited STL values of >20 dB over 125–5000 Hz and had a sound transmission class rating of 34. The study highlights the potential of circular maze-like space-coiling-based acoustic disk metastructures to be reconfigured into metatiles and assembled into a metacage or metapanel for practical sound mitigation applications.