Design of Fano resonance-like acoustic metamaterials for low-frequency acoustic isolation

Due to the poor low-frequency noise reduction, low noise reduction and poor ventilation performance of the current railroad sound barriers, the research in this paper innovatively designs an acoustic metamaterial based on the Fano-like resonance principle, aiming to significantly enhance the insulation effect on low-frequency noise. The interference between the resonant scattering based on the discrete state and the background scattering in the continuous state is utilized, thus inducing a Fano-like asymmetric transmission profile. The metamaterial single cell is a wrap-around labyrinth structure, and the Fano resonance-like low-frequency acoustic isolation type metamaterial acoustic barrier is obtained by arranging it periodically. The structure is designed to be a geometry that takes into account the acoustic isolation effect and ventilatable omni-directionality, and the hollow part is also able to save the cost. Firstly, the geometrical configuration of the metamaterial cell and the theory of sound transmission are introduced, and the influence of structural parameters on the performance of the proposed acoustic metamaterial is analyzed, which provides an important basis for optimizing its acoustic properties. In addition, numerical simulation and simulation analysis of the metamaterial properties are carried out to explore its acoustic properties in depth, and the average acoustic transmission loss of the structure is calculated to be about 50 dB at 20,2900 Hz. The acoustic barrier is modeled by periodically arranging the metamaterial units nested inside the unit plate, and it is found that the increase in the number of metamaterial units does not affect the acoustic performance of the acoustic barrier. Finally, the 3D printed acoustic metamaterials are subjected to acoustic experiments to verify the accuracy of the simulation results, which provides ideas for sound barrier design and engineering applications.