A Semi-Empirical Model for Sound Absorption by Perforated Plate Covered Open Cell Foam and Improvements from Optimising the Perforated Plate Parameters

Composite structures can be designed with specific parameters for efficient sound absorption in specific frequency bands; however, determining the optimal parameters and topology to maximize sound absorption is a computationally challenging task. In this work, a semi-empirical model is constructed to predict the sound absorption performance of composite structures consisting of open-cell foam and perforated plates. The calculated results of the semi-empirical model are in good agreement with the experimental results carried out in the B and K tube impedance measurement system. The parameters such as perforation ratio, plate thickness, air gap, etc., of the composite structure within limited thickness were optimized by using a genetic algorithm (GA) to improve the sound absorption coefficient at a lower frequency band. The calculation and experimental results show that when the thickness is fixed, the peak sound absorption frequency can be reduced by 400 Hz; on the contrary, with the goal of broadening the sound absorption frequency band, the optimized composite structure can widen the sound absorption frequency band by 55.38%. The results of this work have potential engineering applications for the calculation of the sound absorption of porous materials and perforated plate composite structures and their optimal design, particularly when the total volume or total weight of the sound-absorbing material is strictly limited.