Enhancement of sound absorption performance of Helmholtz resonators by space division and chamber grouping

Abstract

Sound absorption performance of the Helmholtz resonator was enhanced by space division and chamber grouping in this research, which aimed to achieve high sound absorption coefficient and broad absorption band simultaneously. Based on acoustic finite element simulation, it could be found that the effective sound absorption frequency band of multiple divided Helmholtz resonators shifted to high frequency direction and the effective absorption bandwidth rose gradually with the increase of division number Ns from 1 to 24, and the effective sound absorption band of multiple divided and grouped Helmholtz resonators with the certain division number Ns would shift to the high frequency direction gradually and its width was improved normally with the increase of grouping number Gs. Moreover, the multiple divided and grouped Helmholtz resonators with division number Ns = 18 and grouping number Gs = 6 was optimized for the certain practical demand, and the optimal geometric parameters were obtained by the joint simulation method incorporating the finite element simulation and the cuckoo search algorithm. Furthermore, its actual sound absorption coefficients were obtained through sample fabrication by the additive manufacturing and standing wave tube measurement by the AWA6290T, and all the actual sound absorption coefficients in 400–800 Hz were above 0.8 and the average value in this range was up to 0.8729 with limited total thickness of 40 mm. Enhancement of the sound absorption performance of multiple divided and grouped Helmholtz resonators would be favorable to promote the practical applications of acoustic metamaterials in the noise reduction field.