Numerical simulation and experimental study on the vibration reduction mechanism of four-component local resonance metamaterial with a discrete soft layer

Metamaterials can effectively attenuate elastic waves within specific frequency ranges. Continuous soft layers, which are employed in traditional local resonance metamaterials, have been studied extensively. To broaden the band gap range, the discrete four-component local resonance metamaterial (LRM) is proposed in this paper, and the traditional four-component local resonance metamaterial is compared. Four different unit cell models are established, including the traditional LRM model, a model of the vertical discrete soft layer, a model with a rubber layer added at the bottom of the oscillator, and a model of the vertical discrete soft layer with a rubber layer added at the bottom. The vibration reduction characteristics of LRMs are evaluated by band gap and transmission models. The scaled experiments are employed to verify the vibration reduction performance and the accuracy of the numerical simulation. The similarity between the band gaps of the model and the prototype is explored. The results show that the cell eigenfrequency is reduced by decreasing the horizontal and vertical stiffness of the soft layer, resulting in a widened band gap. Compared with the initial frequency of 15.27 Hz of the traditional LRM band gap, the initial frequency of the LRM band gap with discrete soft layers can be reduced to 6.1 Hz, and the band gap width is extended by 9.35 Hz in this paper. The attenuation zone derived from the scale experiment closely match the band gap observed from the numerical simulation. The band gap of the prototype can be determined through model inversion using similarity analysis. • A four component local resonance metamaterial with discrete soft layer is studied. • The scale model testing of four component local resonance metamaterial is conducted. • The feasibility of local resonance metamaterial for practical engineering is studied. • The inverse relationship of cell size and band gap is obtained by similar analysis.