Sound absorption property and prediction model of flexible composite fabric material with periodic acoustic units

Perforated panels (PP) and porous materials are often combined to achieve the excellent wide-band sound absorption effects. However, hardness, restricting structural change, unstable laminated structure and thickness limit the improvement of its acoustic performance. This paper puts forword a new composite fabric sound-absorbing material with a structure featuring inner periodic rigid PP units and outer flexible fabric design. The total area of PP had been decreased by 29% ∼ 54% in the new structure (FPP). Sound absorption coefficient and the specific acoustic impedance results showed that the new FPP absorber had the similar or the higher sound absorption peak value (>0.920) compared the laminated structure in the frequency range of 48 ∼ 1700 Hz. FPP absorbers with PP units size 7 ∼ 65 mm exhibit excellent half-absorption bandwidth (1185 ∼ 1312 Hz) in the frequency range of 48 ∼ 1700 Hz. The sound absorption peaks shift towards the lower frequencies by increasing the size of periodic PP unit. The new prediction model based on the equivalent circuit method has been established for predicting the sound absorption of the new structure. This work provides a new strategy for the broad application of acoustic PP or fiber material.