6533b7d3fe1ef96bd125fce9

RESEARCH PRODUCT

On the measurement and prediction of the sound absorption coefficient of air-cavity backed perforated plates considering the holes interaction effect under low sound excitation

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International audience; This paper deals with the measurement and prediction of air cavity backed perforated plates considering the holes interaction effect under relatively low sound excitation. A revised expression for the radiation contribution is proposed to properly account for the holes interaction effect. This expression is integrated in the characteristic impedance expression following Atalla and Sgard [J. Sound Vib. 303, 195-208 (2007)] model. Perforated plate specimens with different centre-to-centre holes distances (pitches) are built and tested using an impedance tube. The particular cases of holes interaction effect with constant low porosity and of holes interaction effect with variable high porosity are depicted and discussed in detail. For the case of constant low porosity, the resonance frequency is observed to decrease with the pitch. For the case of variable high porosity, the resonance frequency increases when the pitch diminishes.