Parametric study and inverse design of perforated silicone auxetic structures

Abstract

A parametric analysis was conducted to determine the influence of geometric parameters on the Poisson’s ratio of an auxetic structure. The results show that, for the selected geometry, the Poisson’s ratio can be precisely adjusted between -0.8 and 0.2 by modifying the geometry. Four different auxetic structures were analyzed through both experimental measurements and finite element simulations, demonstrating a strong correlation between numerical and test results until the onset of wrinkling, which introduces deviations in transverse deformations. The wrinkling phenomenon was identified in all examined auxetic structures. The critical stretch values at which wrinkling occurs were quantified using single-view motion tracking without the need for side-view imaging. A sixth-order Ogden hyperelastic model was fitted to uniaxial test data and refined using a custom parameter-fitting algorithm, ensuring accurate material representation. The developed finite element model was extended to three-dimensional cases, and the auxetic behavior of a 3D auxetic cube was analyzed, highlighting its anisotropic properties. The proposed methodology enables the targeted design of auxetic structures with predefined mechanical responses, making it applicable to a wide range of engineering applications.