Acoustic performance analysis of bionic coupling multi-layer structure

The interest of this paper lies in the proposition of using bionic method to develop a new sound absorption structure. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird – owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The impedance transfer method is applied to calculate the absorption coefficients and analyze the influences of different parameters of each layer on absorption coefficients of this model. Based on numerical simulations, the effectiveness of this proposed model is tested. The average absorption coefficient reaches 0.85 within the frequency range from 200 Hz to 2000 Hz. The significant improvement of absorption coefficients can be mainly due to the Helmholtz effects of the micro-silt plate and flexible micro-perforated membrane, and the combination with porous materials can lead to even better absorption performance in broadband.