Mechanics and extreme low-frequency band gaps of auxetic hexachiral acoustic metamaterial with internal resonant unit

Abstract

Due to the characteristics of light weight, high specific strength, and excellent damping, auxetic honeycomb structures recently attracted widespread attention. The novel structure with low-frequency vibration isolation and load-bearing capacity became one of the current research hotspots through the improved lattice topology design and associated parameters. For this reason, the authors proposed an auxetic hexachiral acoustic metamaterial with an internal resonant unit. The mechanical properties and band gap (BG) characteristics were analyzed using the finite element method (FEM), and the numerical results were further verified experimentally. Furthermore, the influences of lattice topology parameters on the performance of the above-listed aspects were discussed. Results have shown that the novel metamaterial with extreme low-frequency elastic wave BG and improved mechanical properties can be obtained by combining the hexachiral frame with the internal local resonance unit.