A novel buckling-induced planner isotropic auxetic meta-structure and its application in BRB: A numerical study

Recently, anti-tetra-chiral-type bulking-induced auxetic meta-structure (generated by arraying periodic orthogonal elongated holes onto a sheet structure) was proved to exhibit superior aseismic performance. Anti-tetra-chiral-type auxetics, however, present strong anisotropic performance, which may limit their potential applications, as proper structural orientations are required during operations to utilize the beneficial auxetic effect. In analogy with anti-tetra-chiral-type bulking-induced auxetic meta-structure, an anti-tri-chiral-type bulking-induced auxetic meta-structure was therefore proposed by arraying periodic tri-dumbbell-shaped holes onto a sheet structure. Systematic finite element (FE) analyses were then conducted on a unit cell with periodic boundary conditions to elucidate the deformation mechanism and investigate the effective mechanical properties of the proposed auxetic meta-structure. Results show that the proposed design exhibits excellent auxeticity and planner isotropy. A novel auxetic buckling restrained brace (BRB) core brace was then designed based on the proposed auxetic meta-structure. Numerical calculations were then conducted to investigate the aseismic performance of the proposed auxetic BRB core. It is shown that the proposed auxetic BRB core brace demonstrates better energy dissipation capacity compared to a traditional BRB core brace with positive Poisson's ratio and a recently reported auxetic BRB core brace with orthogonal elliptical holes. Practically, the aseismic performance of the proposed BRB core brace is independent of the orientation of the perforated holes and hence can allow uncertain fairly big manufacturing errors.