Energy Absorption by 3D-Printed Mesh Structures with a Negative Poisson's Ratio

A negative Poisson's ratio (NPR) structure represents optimal impact-resistance with applications in various fields, including the crash box in vehicles, which absorbs impact kinetic energy. The crash box is designed to deform in response to impact, increasing local structural density, which enhances impact resistance performance. Current studies have only focused on the NPR effect in the plane dimension at low-speed loads. Few studies have considered high-speed impact loads on three-dimensional NPR structures. We have developed two types of AlSi10Mg alloy energy-absorbing structures with NPR using three-dimensional printing technology, and have compared our systems with a conventional hexagonal mesh structure. Sample testing involved split-Hopkinson pressure bar measurements, which showed good agreement with dynamic numerical simulations. When subjected to an impact load, the NPR structure exhibited better impact resistance and energy absorption compared with the positive Poisson's ratio structure. The proposed dual-layer hexagonal structure ensures an NPR effect while exhibiting higher strength and improved stability relative to the conventional concave hexagon structure.