Design a special micro-perforated plate coupled with the labyrinth metamaterial with improved sound absorption properties at medium and low frequencies

The micro-perforated panel structure has good sound absorption performance in medium and high frequencies, and the labyrinth metamaterial structure has good low-frequency sound absorption performance. Both the two structures are relatively simple, and can be obtained by simple processing with resin material, which is convenient for batch production. In order to enhance sound absorption ability for the sound absorption structure within low frequency, this research work has put forward one coupled structure via the micro-perforated panel and three second-order maze metamaterials structure, resulting in a coupled structure with a low-frequency sound absorption performance. Combination of equivalent circuit method calculates acoustic resistance and absorption coefficient for the sound absorption structure, and genetic algorithm has been employed to optimize the parameters of this sound absorption structure. Finally, the theoretical calculations analysis results have been verified by finite element simulation, which shows the trend of the curve of sound absorption coefficient of the two structures was basically consistent. And the sound absorption coefficient of the three peaks is all above 0.7, and the mean value of the sound absorption coefficient is above 0.6 at the acoustic frequency of 0–1500[Formula: see text]Hz, indicating that the coupled structure has a good performance of absorbing medium- and low-frequency sound waves.