Tunable mechanical properties of the 3D anticircular-curve transversal-isotropic auxetic structure

This work studies a three-dimensional anticircular-curve transversal-isotropic auxetic structure (3D-ATAS) with tunable Poisson's ratio (v) and tunable Young's modulus (E) on the basis of hexagonal symmetry in the transverse plane using the anti-deformation method by the design of inclined rods as circular-curve rods in the opposite direction of the deformation (under compressive loading). By using the energy method, expressions of v and E of 3D-ATAS are acquired, and based on the periodic boundary conditions, v and E of 3D-ATAS are parametrically researched through numerical simulation and uniaxial compression experiments. The effects of anticircularcurve rod thickness t, anticircular-curve rod width b, and anticircular-curve cross-section angle B to v and E of 3D-ATAS are investigated. The tunable ranges of v and E of 3D-ATAS are predicted, and the wide range of E is attained. Compared with the 3D circular-curve transversal-isotropic auxetic structure, E of 3D-ATAS is significantly enhanced in different directions, and the maximum enhanced up to 10 times. In the same way, both v and E of 3D-ATAS are transversal-isotropic.