Design of subwavelength broadband hybrid sound absorption structure based on micro-perforated plate and coiled channels

In this paper, we propose a hybrid subwavelength broadband sound absorber based on micro perforated plate and multiple coiled channels. And the mechanism of low frequency broadband sound absorption of the hybrid sound absorber is analyzed in detail. Based on this, the theoretical analysis model and the finite element numerical analysis model are established, and the mutual verification of theoretical and numerical solutions is completed. The structure can theoretically achieve the low-frequency and high-efficiency sound absorption with an average absorption coefficient of 0.8 in a frequency band of 200-500 Hz when the overall thickness of the sound absorbing structure is 60 mm. At the same time when the overall thickness is 90 mm, quasi-perfect sound absorption with peaks up to 0.95 in a frequency range of 180-350 Hz is realized theoretically. The composite sound absorption structure has a certain application prospect in engineering low frequency noise in future.