Ultra-broadband acoustic ventilation barriers via hybrid-functional metasurfaces

TL;DR

This paper presents a novel hybrid-functional metasurface that achieves ultra-broadband acoustic ventilation barriers, effectively blocking over 90% of sound across a wide frequency range while allowing airflow, with experimental validation.

Contribution

The authors introduce a hybrid design combining dissipation and interference to significantly expand broadband sound blocking capabilities in ventilation barriers.

Findings

Effective sound blocking from 650-2000 Hz exceeding 90%

Structural thickness of only 53 mm (~λ/10)

Flexible customization for various broadband and directions

Abstract

Ventilation barriers allowing simultaneous sound blocking and free airflow passage are of great challenge but necessary for particular scenarios calling for sound-proofing ventilation. Previous works based on local resonance or Fano-like interference serve a narrow working range around the resonant or destructive-interference frequency. Efforts made on broadband designs show a limited bandwidth typically smaller than half an octave. Here, we theoretically design an ultra-broadband ventilation barrier via hybridizing dissipation and interference. Confirmed by experiments, the synergistic effect from our hybrid-functional metasurface significantly expand the scope of its working frequencies, leading to an effective blocking of more than 90% of incident energy in the range of 650-2000 Hz, while its structural thickness is only 53 mm $(\sim \lambda / 10)$. Our design shows great flexibility in customizing the broadband and is capable of handling sound coming from various directions, which has potential in air-permeable yet sound-proofing applications.