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

Abstract

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 220 mm thickness is then manufactured and tested to exhibit ultra-broadband transmission loss overall above 10 dB across the range 0.44–3.85 kHz, 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.

Integrating Renewable Energy in Transportation: Challenges, Solutions, and Future Prospects on Photovoltaic Noise Barriers

“…Therefore, metamaterials can unconventionally manipulate the waves to obtain a deformation of the acoustic field and attenuations that traditional materials do not allow. The results suggest that the barriers obtained with metamaterials can be used to mitigate noise due to road traffic or other noise sources, especially low-frequency noise, which is difficult to control, so they can be a valid substitute for traditional barriers [28]. So, unique structures and shapes of metamaterial noise barriers can be designed based on the frequency band type of noise, site conditions, and surrounding landscape features.…”

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“…[ 136 ] Based on Fano resonance, an ultra‐broadband sound barrier was assembled by space‐coiling metamaterials, which was described by a simplified model of the sound transmission characteristics of space‐wound metamaterials under vertical incidence. [ 137 ] The sound transmission loss of an experimental 220‐mm‐thick sound barrier exceeded 10 dB in the frequency range of 0.44–3.85 kHz, completely covering nine one‐third octave bands.…”

Coupled acoustic resonance for wave control and sensing

“…To understand the interference, the phase spectra of each scattering are plotted in Ref. [66]. In that reference, phases in a frequency range between the two peaks differ by π compared to those of the non-resonant scattering.…”