A Novel Barbell‐Shaped Perforated Auxetic Metastructure with Superior Auxetic Effect

Recently, artificial perforated auxetic metastructures with negative Poisson's ratio have attracted considerable attention with the superior mechanical properties. The concepts and design methods of various types of perforated auxetic metastructures have developed rapidly. However, the effective Poisson's ratio exhibited by the majority of current perforated auxetic metastructures has a lower limit of −1, which restrains their potential applications significantly. Herein, a novel 2D perforated auxetic metastructure is proposed by arraying orthogonal barbell‐shaped holes onto a sheet structure. The mechanical properties and the underlying deformation mechanism of the proposed auxetic metastructure are then investigated by performing experimental tests and finite element simulations. Results show that the lower limit of the Poisson's ratio exhibited by the proposed auxetic metastructure surpasses −1 remarkably and the proposed design hence exhibits much better auxetic performance compared with existing designs. It is also revealed that the proposed design exhibits relatively low local stress distribution. The results of this study will broaden the potential applications of perforated auxetic metastructures in many engineering fields.