Numerical and experimental investigations of a novel 3D bucklicrystal auxetic structure produced by metal additive manufacturing

n this study, a novel 3D-auxetic structure composed of perforated thin hyperbolic shells is designed based on the mathematical bucklicrystal geometry and fabricated using a metal additive manufacturing process. Numerical finite element simulations and uniaxial compression tests are carried out to characterise the mechanical structure properties. The deformation of the structure is analysed using the traditional digital image correlation (DIC) method and a new approach based X-ray computed tomography (CT) scanning analysis. The effect of material and design parameters of the proposed structure on the Poisson’s ratio is investigated to identify the design variables to tune the auxetic behaviour of the structure. The results show that the designed structure exhibits a marked auxetic behaviour with, at the lowest, a Poisson’s ratio of about −6.