Kirigami graphene with architected defects: auxeticity, mechanics and benchmark

This study investigates the mechanical performance and auxetic behavior of graphene Kirigami structures with ordered and disordered perforations, using molecular dynamics simulations. We examine the effects of various perforation shapes—Cassini (peanut-shaped), rectangular, rhombic, and elliptical—on the mechanical properties and auxetic characteristics of graphene. Our results show that both ordered and disordered architected defects significantly enhance the auxetic behavior of graphene, as evidenced by negative Poisson's ratios for all perforation shapes. While increasing disorder reduces the auxetic response, configurations with peanut-shaped and rectangular perforations maintain robust auxetic performance even at higher disorder levels, whereas rhombic perforations exhibit the weakest behavior. Irregularities in the rotation of the perforation elements and out-of-plane deformations are identified as key factors reducing auxetic properties in disordered configurations. These findings provide important insights for designing advanced auxetic metamaterials with applications in flexible electronics, soft robotics, and responsive materials.