Analysis of Programmable Anisotropy and Controllable Deformation of 3D Anticircular-Curve Auxetic Structure and Realization of Extreme Anisotropy

Anisotropic metastructures — advanced engineered materials with direction-dependent mechanical properties — achieve precise controllable deformation by adjusting orientational stiffness. This trait endows them with great promise in aerospace engineering, especially for the dynamic shape adjustment of morphing aircraft. To promote the practical application of such metastructures, this study proposes the 3D anticircular-curve auxetic structure (3D-AAS), engineered through the assembly of complementary curve rods under fourfold rotational symmetry constraints. The energy method is used to derive equations for 3D-AAS’s Young’s modulus and Poisson’s ratio along [Formula: see text]- and [Formula: see text]-directions. Under periodic boundary conditions, the parametric study based on numerical simulations reveals the regulation laws and deformation mechanisms of geometric parameters (the circular-curve angle [Formula: see text], the rod width [Formula: see text] and the rod thickness [Formula: see text]) on Young’s modulus and Poisson’s ratio of 3D-AAS. To validate the accuracy of the theoretical model and numerical results, uniaxial compressive testing is performed on fabricated 3D-AAS specimens. The test results demonstrate excellent consistency between the theoretical predictions and numerical simulation outcomes. It is particularly worth noting that 3D-AAS exhibits orthotropic anisotropy. To quantitatively evaluate the degree of anisotropy, the study defines an anisotropy influence factor [Formula: see text]/[Formula: see text]. It is found that among all the geometric parameters, the circular-curve angle [Formula: see text] exerts the most significant influence on the anisotropy of 3D-AAS, and the largest value of [Formula: see text]/[Formula: see text] reaches 51.45.