Realization of complex curved waveguide based on local resonant 3D metamaterial

To overcome the negative impact of diffraction effect on the transmission wave front at the bend and to improve the transmission efficiency of acoustic wave in the bend waveguide, the finite element method by COMSOL was used to simulate the propagation characteristics of acoustic wave in the structure of bending acoustic waveguide, based on local resonance acoustic metamaterials. Specifically, the vibration mechanism of three-dimensional (3D) component locally resonant phononic crystals was presented, and the acoustic metamaterial models of M-shaped, L-shaped and S-shaped bent waveguides were constructed on the basis of the protocells. The local resonance between the acoustic wave and the protocells in the waveguide model was investigated, in order to produce the nondestructive bending propagation effect of the acoustic wave. The results of finite element analysis show that the plane acoustic waves incident from the M-shaped, L-shaped and S-shaped bending waveguide model will propagate directionally along the model structure after being controlled at the resonance frequency. These results confirm the flexibility and feasibility of the bending acoustic waveguide model designed by the local resonance acoustic metamaterials. In addition, the acoustic waveguide model in long-distance special environment was designed and the low loss transmission of acoustic signal was implemented. This study provides a new solution for engineering applications, such as ultrasonic signal detection and underwater acoustic communication transmission.