Design, manufacture and crushing behaviors of buckling-inspired auxetic meta-lattice structures

Introducing buckling pattern into straight-walled lattice structure, anovel buckling inspired lattice meta-structure (BILM) was designed and fabricated using polylactic acid (PLA) by three-dimensional (3D) printing technology. The square lattice structure with positive Poisson’s ratio (PPR) is transformed into negative Poisson’s ratio (NPR) structure by buckling induction. Curved struts decrease the maximum strain, prohibit strut fracture, increase strut contact and induce ductile bending deformation. The meta-topology changes the crushing pattern from brittle layer-by-layer fracture, hybrid crushing pattern to stable plastic crushing when increasing the central angle from 0° to 120°. Buckling inspired meta-lattice structures can obviously improve the energy absorption (EA) performance through reducing the initial peak force (IPF) while increasing the EA, specific energy absorption (SEA) and crushing force efficiency (CFE). Ductile crushing endows BILM excellent EA.