Tunable band gaps and double-negative properties of innovative acoustic metamaterials

Using monophase core materials to design periodically acoustic metamaterials with vibration isolation properties and special acoustic properties that do not exist in natural bulk solids is a challenging and innovative work. In this paper, we proposed an innovative star-shaped acoustic metamaterials with periodic assemblies based on the double-negative properties generated by rotational resonance, monopolar resonance and dipole resonance. At the same time, the metastructures would generate broad and multiple omnidirectional band gaps through the rotational resonance of the spherical masses. In addition, the rationally designed arc-shaped ligaments could produce reversible deformations under the excitation of external strains, thereby realizing preliminary tuning of the band gaps. Numerical simulations with the finite element method provided effective data support for the above research, and proved that the proposed architected microstructures would provide reference for vibration reduction and the design of acoustic lens metamaterials.