In this paper, we propose a vibration metamaterial that effectively reduces radiated noise and demonstrate its performance in reducing radiated noise through experiments. Using a spiral beam-shaped absorber as a unit cell, local vibration is generated in the target frequency band. The dispersion curve calculated using the plane wave expansion method is compared with the finite element analysis result, and the relationship between the band gap and the radiated noise reduction band is identified. The effects of the dimensions, mass, and resonant frequency of the spiral absorber on the band gap are investigated. Based on these results, a unit cell for reducing radiation noise generated by the first natural mode of the beam is designed. The validity of the design result is verified through the vibro-acoustic reciprocity-based experiment for the vibration metamaterial. The results of this study can be applied to the suppression of radiated noise generated outside by panel vibration by mounting it inside the panel surrounding the mechanical product.
