Tunable Elastic wave Bandgaps and Waveguides by Acoustic Metamaterials with Magnetorheological Elastomer

There is proposed a tunable acoustic metamaterials cell composed of a micro-electromagnetic coil as the mass element and a magnetorheological elastomer (MRE) as cladding layer. The cell resonance frequency is changed by changing the magnetic field generated by the micro-electromagnetic coil to control the shear modulus of the MRE cladding layer. The tunable bandgaps, transmission loss, and waveguides of the tunable acoustic metamaterials are investigated using the finite element method. The results show that the bandgap frequency and width, the maximum attenuation frequency and transmission loss increase with the increasing of applied magnetic field strength. Meanwhile, without changing the structure of the acoustic metamaterials, the localization, guidance, demultiplex and multiplex of elastic waves can be realized by changing the cell resonance frequency. These results will greatly contribute to the application of tunable acoustic metamaterials in vibration control, new waveguides, and filter components.