Sound absorption analysis of a metamaterial based on parallel dual Helmholtz resonators

In this paper, a sound absorbing material consisting of four parallel dual Helmholtz resonators is proposed and its sound absorption coefficient is studied using finite element method. The dual Helmholtz resonator is made of neck-cavity-neck-cavity where each neck extends into each cavity. The sound absorption coefficient of the dual resonator presents two resonant peaks. It is demonstrated that when the radius of the first or the second neck increases, the two resonant frequencies of the sound absorption increase while they decrease when the length of the first or the second neck increases. The proposed material design, which combines four parallel dual Helmholtz resonators, presents eight sound absorption peaks and these eight resonant frequencies can be tuned to specific frequencies by adjusting the parameters of the necks. It is a compact sound absorber, which can help to attenuate the noise simultaneously at eight different frequencies in several engineering applications.