Bio-inspired repeatable lattice structures for energy absorption: Experimental and finite element study

New and innovative lightweight materials are the key demands of the automotive and aerospace industry. Exceptional energy absorption properties can be obtained from designs with local-buckling characteristics. Inspired by many biological designs, bio-inspired structures exhibit a significant progress over the conventional lightweight structures. In this paper, the energy absorption behavior of lattice structures derived from the hexactinellida sea sponge Euplectella aspergillum is studied for the first time. The designed lattice structures are fused filament fabricated with thermoplastic polyurethane material. Energy absorption and deformation behavior are studied under quasi-static loading conditions. The effect of the strut thickness, relative density, and unit cell size on the energy absorption is studied both experimentally and numerically. The structures are designed to increase the energy absorption capacity with a stable plateau region without compromising the mean plateau stress. The bio-inspired lattice structures showed a local buckling other than the global buckling mode of deformation. The cyclic loading–unloading of the structures was also carried out to study their compressive behavior and repeatability. The structures underwent a softening effect over the first cycle and become stable from the second cycle onwards. Hence, the improved energy absorption capacity, stable post-yielding stress, and high mean value stress can be used to develop better energy absorbers.