Analysis of Sound Absorption Characteristics of Acoustic Ducts with Periodic Additional Multi-Local Resonant Cavities

With the aim of applying various Helmholtz resonant cavities to achieve low-frequency sound absorption structures, a pipe structure with periodic, additional, symmetrical, multi-local resonant cavities is proposed. A thin plate with additional mass is placed in the cylindrical Helmholtz resonant cavity structure to form a symmetric resonant cavity structure and achieve multi-local resonance. The simulation results show that the periodic structure proposed in this paper can produce multiple, high acoustic transmission loss peaks and multiple lower broadband sound absorption frequency bands in the low-frequency range. In this paper, this idea is also extended to the Helmholtz resonant cavity embedded with multiple additional mass plates. The results show that the periodic arrangement of the multi-local resonant symmetric cavity inserted into multiple plates with mass can significantly increase its transmission loss and show a better performance on low-frequency sound absorption characteristics.