Enhanced sound absorption performance of stepped-type multi-cavity acoustic absorbers using a hybrid particle swarm algorithm

A stepped-type multi-cavity combined sound absorber (SMCSA) was developed to improve the low and mid-frequency sound absorption capabilities of micro-perforated panels. The sound absorption characteristics of the SMCSA were thoroughly investigated using experimental methods, theoretical calculations, and numerical simulation. The particle swarm optimization algorithm was employed to optimize the SMCSA parameters. The findings revealed that the board thickness, hole size, and cavity depth significantly influenced the sound absorption properties of the SMCSA. When the hole size ranged from 0.4–0.6 mm, the sound absorption coefficient of the SMCSA reached 0.9, and the resonance frequency was 600–800 Hz. After optimization utilizing the hybrid particle swarm algorithm, the maximum sound absorption coefficients at the resonance frequency of the two-step, four-step, and eight-step structures were all 0.99.