Bandgap Coupling Characteristics of a Tunable Metamaterial with Double Magnetic Resonators
Elastic wave metamaterials are artificial periodic structures that can control elastic waves.They can be used in aeronautics and astronautics,vehicle engineering,and other fields.This paper propo-ses a tunable metamaterial with two magnetic resonators.In this structure,a stainless steel plate connects the magnetic resonator to the external frame.Adjusting the distance between the magnets can affect the in-plane stress of the stainless steel plate and thus the internal stiffness.By adjusting the cell structure,a double-cell system with different internal stiffnesses can be formed to achieve a wider coupling band gap.First,the variations of the stiffness of the thin plate and the negative stiffness of the magnetic force with the distance between two magnetic resonators are determined.The dispersion relationship and the trans-missibility of the single-cell metamaterial with double magnetic resonators and the double-cell metamaterial formed by adjusting the distance between magnets are obtained using a theoretical model.Then,the effect of the distance between two magnetic resonators on the metamaterial bandgap and double-cell coupled bandgap in a specific case is further studied.Finally,an experimental model is designed and manufactured using 3D printing technology.The transmissibility curves at different distances between two magnetic re-sonators are measured,and the bandgap coupling results of double-cell metamaterial structures are veri-fied.The theoretical prediction of the bandgap of the metamaterial agrees well with the experimental re-sults.This adjustment method can provide a new idea for the active control of restraining elastic wave transmission.
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