A design method of acoustic metamaterials with buckling vibrators

This paper proposes a periodic acoustic metamaterial with buckling vibrators, and investigates the design method for the band-gap characteristics of the acoustic metamaterial. The unit cell of the acoustic metamaterial is constructed by a continuous bar, curved beams embedded into the bar and the mass supported by the curved beams. The band structure of infinite period and the transmission characteristics of finite period are researched to analyze the effect of the structural and material parameters of the curved beam on the band-gap characteristics of the unit cell. And the effect of pre-strains applied to the curved beam on the band-gap characteristics is also discussed. The research illustrates that the acoustic metamaterial with buckling vibrators has a low frequency band-gap of 100-125Hz; in the frequency range of 0-200Hz, the central frequency of the band-gap increases with the increase of the beam width; the curvature radius of the beam has little influence on the central frequency of the band-gap, and a big bandwidth of the first band-gap can be obtained when the curvature radius is 20 mm; by applying pre-strain to the curved beam in a certain extent, the central frequency of the band-gap can be effectively reduced, and the attenuation more than 100 dB can be guaranteed.