Shear behavior of auxetic and non-auxetic cellular metamaterial

Classical cellular auxetic materials typically exceed the linear elastic small-deformation regime, leaving the superiority of their shear performance unclear. Therefore, it is essential to investigate the shear performance of classical auxetic structures and compare their shear resistance with non-auxetic structures. In this work, a shear deformation performance test was conducted on three classical auxetics (reentrant structure (Re), Star lattice (St), and chiral lattice (Ch)) and two non-auxetic counterparts (Honeycomb structure (Ho), near-zero Poisson’s ratio semi-reentrant structure (Se)) experimentally and numerically. The optimal mesh size was determined via grid convergence analysis. Then, the effective shear modulus of the structures was measured via the modular picture-frame apparatus. Deformation mode indicate that shear force magnitude depends on rib arrangement within the unit cell. Parametric analyses were conducted on the reentrant structure and chiral lattice by varying rib thickness, unit cell size, and number of unit cells. The results show that auxetic structures exhibit significant differences in shear modulus compared to two non-auxetic structure, with far lower shear stress during deformation. The rib thickness of the unit cell had the greatest impact on shear stress. This study highlights that the advantage of auxetic structures lies not in enhanced shear modulus but in their exceptional deformation capacity. Leveraging this property, auxetic structures offer innovative potential applications in civil engineering and aerospace engineering, such as architectural membranes and aircraft wing skins.