Energy Absorption of Additively Manufactured Tubular Honeycomb Structures Employing Buckling Initiators Under Quasi-static Crush

The utilization of additive manufacturing in producing tubular honeycomb (THC) structures, leveraging capabilities of fused filament fabrication, enables the introduction of attributes, such as buckling initiators, to augment energy absorption characteristics. Increasing crush efficiency and/or energy absorption efficiency of THC structures bolsters payload and occupant protection in vehicular systems during impact scenarios such as collisions for ground vehicles or harsh landings for aircraft. In this investigation, THC structures composed of acrylonitrile butadiene styrene (ABS) plastic were additively manufactured so that buckling initiators (BIs) could be efficiently incorporated in the THC structure and readily positioned at the top, 3/4 height, or half height of the samples. Each configuration was subjected to quasi-static (0.03 mm/s) and constant (0.5 m/s) velocity testing employing an MTS machine, with three specimens manufactured for each test condition. Results demonstrated a notable 12.60% increase in energy absorption efficiency and a 15.75% increase in crush efficiency for specimens featuring BIs at the top of the sample as compared to those without BIs under quasi-static conditions. Furthermore, substantial improvements were also observed under constant velocity testing, indicating the efficacy of BIs at the top of the sample in promoting structural folding and progressive collapse, thereby increasing crush energy absorption and crush efficiency.