Multi-band acoustic topology construction by spatial stacking

Currently, the development of multiband acoustic topological systems is constrained by the dimensional characteristics of scattering elements. The number of bands in edge mode is limited and the bandgap width is also affected. Therefore,this paper presents a construction method for multi-band acoustic topology through spatial stacking. This method mainly involves stacking of resonant cavities in the vertical spatial direction of the scatterer, and utilizes the local resonance of the resonant cavities to excite additional operating frequency bands. Compared with the conventional acoustic topology, it can break the limitation of structure size and improve the space utilization. The results simulated by finite element simulation show that more number of working frequency bands can be constructed by superposing resonant cavities in its vertical spatial direction. Moreover, the number of layers of spatial stacking is positively correlated with the number of working bands. Finally, we focus on the acoustic topology when the space is superimposed to three layers of resonant cavities, and verify the correctness of this method by experimentally comparing and demonstrating that there are indeed ten effective acoustic transmission channels. This study breaks the limitation of the traditional acoustic topology in terms of structural size and realizes the construction of more operating frequency bands, which provides a new idea for the acoustic control field of multiband acoustic topology, multiband filter and acoustic sensor.