A Fano-based acoustic metamaterial for ultra-broadband sound barriers

Ultra-broadband sound reduction schemes covering living and working noise spectra are of high scientific and industrial significance. Here, we report, both theoretically and experimentally, on an ultra-broadband acoustic barrier assembled from space-coiling metamaterials (SCMs) supporting two Fano resonances. Moreover, acoustic hyper-damping is introduced by integrating additional thin viscous foam layers in the SCMs for optimizing the sound reduction performance. A simplified model is developed to study sound transmission behaviour of the SCMs under a normal incidence, which sets forth the basis to understand the working mechanism. An acoustic barrier with 220mm thickness is then manufactured and tested to exhibit ultra-broadband transmission loss overall above 10 dB across the range 0.44-3.85kHz, covering completely nine third-octave bands. In addition, unconventional broadband absorption in the dampened barrier (65%) is experimentally observed as well. We believe this work paves the way for realizing effective broadband sound insulation, absorption and sound wave controlling devices with efficient ventilation.

Automated summary

An ultra-broadband acoustic barrier assembled from space-coiling metamaterials supporting two Fano resonances is reported, with additional thin viscous foam layers for acoustic hyper-damping. Experimental results show over 10 dB reduction in noise transmission loss across a specific range, along with unconventional broadband absorption observed in the dampened barrier.