Effect of geometrical parameters and additional mass on the acoustic and vibration control of the bilayer resonant metamaterials

Due to the advantages of lightweight, small size, high stiffness, and adjustable parameters, plate metamaterials have shown great practical application value in the field of acoustic vibration control in engineering. For low-frequency vibration and noise control, an annular slotted bilayer plate metamaterial is designed, which can realize sound insulation and vibration reduction at 100–150 Hz (low-frequency range). By changing the geometric parameters of the annular slotted bilayer plate, the structural parameters of the additional mass, the material parameters, and its distribution position, the acting frequency band is reduced and the band gap of sound insulation and vibration reduction is widened. The integral metamaterial panels of circular and square PA12 were fabricated by 3D printing technology, and then, the acoustic and vibration characteristics were tested in the ZK1030 impedance tube system and Polytec full-field scanning laser vibration measurement system, respectively. The results show that the structure has the best performance by varying the resonant ring thickness of the lattice structure, controlling the wave incidence angle to 0°, and pointing force excitation in the X direction. However, when the mass of the additional mass block is certain, the distribution position of the mass block has less effect. The experimental result was reasonably consistent with the simulation analysis result. This work can provide a reference for the design of bilayer plate acoustic metamaterials with low-frequency broadband acoustic insulation and low-damping vibration based on periodic structures in engineering.