A mechanical metastructure with switching Poisson’s ratio and tunable band gaps

Abstract In this paper, a mechanical metastructure with switching Poisson's ratio is proposed by combining the re-entrant honeycomb and octagonal honeycomb. The combined mechanical metastructure can enable the structure to transition from a negative Poisson's ratio to a positive Poisson's ratio, or from a zero Poisson's ratio to a positive Poisson's ratio. Meanwhile, the load-bearing capacity and vibration isolation of the mechanical metastructure change with the Poisson's ratio of the structure varies. The relationship between the Poisson's ratio of the mechanical metastructure and its compressive force with band gap is investigated. The results indicate that the Poisson's ratio variation of the metastructure significantly affects its compressive force and band gap. The compressive force of the mechanical metastructure in either the negative or zero Poisson's ratio state is lower than that in the positive Poisson's ratio state. Moreover, broad band gap can be achieved in the combined mechanical metastructure and the structure exhibits different band gap and frequency range in distinct Poisson's ratio states. Transmission spectrum and mode shapes are utilized to demonstrate the underlying mechanisms of wave attenuation. The proposed mechanical metastructure demonstrates significant potential for applications in structural health monitoring and vibration isolation, providing a valuable reference for the multi-functional design of mechanical metastructures