Absorption of Finite-Band Sound by Dynamic Material Properties

A resonator array can broaden the effective sound absorption bandwidth by using the structure with multiple cavities in parallel (or in series) in space. However, this kind of fixed mechanical structure cannot flexibly adapt to different noise sources, which severely limits the development prospect of the resonator array in practical applications. In this paper, a time-varying resonator is proposed based on a shunted electrical circuit, realizing the equivalent effect of cavities in parallel in space. Based on the working principle of spatial parallel and temporal series resonators, theoretical models are established, and then two designs for achieving broadband effects are analyzed theoretically. Through time-domain numerical calculation, the sound absorption performance of two different designs with the same cavity volume is obtained. Compared with the spatial parallel resonator, the proposed temporal series resonator has the advantages of tunable frequency and high adaptability of the varying source while achieving similar or even better sound absorption performance.