Crashworthiness design for trapezoid origami crash boxes

A thin-walled tube referred to as trapezoid origami crash box is recognized as an energy absorption device. The surface of this tube is prefolded in the light of a developable origami pattern that is delicately designed to introduce a special structure on the surface of a square tube. This special structure, known as trapezoid folded lobe, is employed as a type of geometric imperfection to lower the peak force and as a mode inducer to trigger the complete diamond mode. The quasi-static numerical simulations reveal that the complete diamond mode is successfully triggered. Moreover, geometric and compliance analysis suggest that three key parameters, the number of module M, dihedral angle theta and area ratio omega, could greatly affect the collapse behavior. Based on those analysis, an optimal trapezoid origami crash box is designed to compare with the conventional square and octagonal tubes of identical weight. Furthermore, a series of diamond origami crash boxes are analyzed to compare with the trapezoid origami crash boxes. The comparative results show that the trapezoid origami crash box is the most desirable in terms of energy absorption.