Negative Poisson's Ratio Lattice Structure with Chiral and Re-Entrant Properties

Materials exhibiting negative Poisson's ratio (NPR) effects possess several advantageous properties, including high specific strength, specific stiffness, and impact resistance. As a result, they hold significant importance in various industries such as aerospace, medicine, transportation, sports, and other related fields. In the realm of natural materials, the NPR effect is infrequent. Consequently, the creation of an NPR structure necessitates a manual design. In this paper, we present an architected lattice system inspired by ancient Chinese window grills. The proposed system exhibits a unique combination of chiral and re-entrant properties. Experiments and numerical simulations were conducted in order to quantify the variation in NPR and elucidate the deformation mechanism of window grill structures. We observed a significant NPR effect in our designed structure, which was found to be dependent on the geometric parameters of the structure. The present study provides a foundation for the development of a new category of partially auxetic lattice metamaterials and the expansion of their design possibilities.