Tuning the band structure of assembled anti-tetrachiral metamaterials

Metamaterials with synthetic repeating units can achieve plane wave attenuation through the local resonance inside the microstructure units and produce extraordinary physical properties under the excitation of low-frequency elastic waves. In this work, innovative assembled anti-tetrachiral metamaterials (AAMs) with deformable curved ligaments were proposed, in which soft rubber-coated mass inclusions were embedded as resonators to construct low-frequency band gaps. Band structures, formation mechanisms of the band gaps, effects of the resonator configuration on the band gaps and elastic wave transmissions of the finite structures were systematically studied by means of finite element simulation. Additionally, reversible deformations caused by external tensile strains were introduced to the boundary of global artificial metamaterials which composed of nearly incompressible hyperelastic materials to realize band gap tuning. Numerical results showed that the carefully designed metastructures easily create low frequency and tunable band gaps, and the potential application value of our metamaterials in vibration and noise reduction projects was demonstrated.