Weak stiffness-induced regulation of strongly directional waveguides in anti-tetrachiral spiral metamaterials

Abstract

In-plane weak stiffness and low-frequency strong directional wave regulation at high tensile strains are key considerations for engineering applications. To overcome this problem, a novel anti-tetrachiral spiral metamaterial with low-frequency wave regulation under high tensile strain is designed by introducing Archimedean spiral holes into the perforated plate. The wave attenuation properties and Poisson's ratio characteristics of the proposed anti-tetrachiral spiral metamaterial are investigated through numerical simulations and experimental testing of prototype samples fabricated by additive manufacturing. The results show that weak stiffness is the key factor contributing to the low-frequency bandgap (BG) and zero Poisson's ratio (ZPR) characteristics. The Bragg-type and local resonance-type wave can be interconverted by regulating the stiffness to possess the low-frequency strong wave attenuation capability. The BG frequency of the proposed metamaterial is reduced to 7.88 ‰ of a conventional perforated plate, and its tensile stiffness and maximum mises stress are reduced to 0.23 ‰ and 12.12 ‰ of a conventional perforated plate. Furthermore, the design of four types of waveguide paths with negligible susceptibility to tensile deformation. ZPR structures at weak stiffness have strong directional wave regulation capability in the low-frequency domains, which enables stable wave transport properties independent of tensile deformation. The designed ZPR structures with low in-plane stiffness and low-frequency BG characteristics as well as the strong directional wave regulation are expected to play a key role in the design of future high-performance waveguide devices and tunable BG materials.