On bending crashworthiness of smooth-shell lattice-filled structures

Thin-walled structures are widely used in engineering applications. In order to improve the mechanical properties of thin-walled structures, porous structures are usually filled into thin-walled tubes. However, the widely used porous structures have the disadvantages of randomness, heterogeneity and anisotropy. Recently, a novel porous structure called as smooth-shell lattice has gain attention for its high energy absorption capacity. The crashworthiness of thin-walled tube may be highly improved if it is filled by smooth-shell lattice. However, there are few researches on studying the crashworthiness of the smooth-shell lattice-filled structures. To this end, the bending crashworthiness of the smooth-shell lattice-filled structure is investigated jointly using experiment, numerical simulation and empirical formula in this study. The smooth-shell lattice of this study is constructed based on the triply periodic minimal surface (TPMS). Three kinds of TPMS-based smooth-shell lattices are considered in our study. The influence of the design parameters such as the shell thickness of lattice, unit-cell size of lattice and thickness of tube on the crashworthiness is studied. In order to obtain the optimal designs of smooth-shell lattice-filled structures, the PRS metamodels and NSGA-II are employed, while the peak crushing force (PCF) and specific energy absorption (SEA) are chosen as the optimization objectives. The force–displacement responses of three filled-tubes are fitted in the end. The investigation results show that the smooth-shell lattice-filled tube has more bending crashworthiness than the traditional foam-filled tube with the same weight. The smooth-shell lattice-filled tube can be used as excellent energy absorption structure in impact engineering. • The bending crashworthiness of the smooth-shell lattice-filled structure is first investigated. • The three-point bending experiment is carried out for the smooth-shell lattice-filled structure. • The bending crashworthiness of the smooth-shell lattice-filled structure is optimized. • The empirical formula for the bending force of the smooth-shell lattice-filled structure is given.