LAUSR

Broadband acoustic absorption at deep sub-wavelength has become a research hotspot, while current methods still suffer from thick structures and narrow bandwidth. This study proposes an origami-based foldable sound absorber based on micro-perforated resonators. The origami acoustic absorber is composed of six different channels. The resonance frequency of each channel can be easily tuned by origami process under the deep sub-wavelength thickness. When the structure is folded, the thickness is only 20 mm to 30 mm. The operating bandwidth can be tuned from 55 Hz to 80 Hz in the frequency range of 305 Hz to 540 Hz, where the average sound absorption coefficient is beyond 80%. Effective absorption can be realized via a design whose average thickness is only 1/34.4 λ for the resonance frequency. This study broadens the sound absorption bandwidth and improves the low-frequency sound absorption ability, which provides an avenue for flexible low-frequency noise control.