Study on crushing behaviors of the crash box with truss-lattice and cellular structures.

Crash boxes are typically designed to promote characteristics in energy absorption from progressive buckling during impact. However, the conventional design often has limitations in lightweight design and passenger protection. Thus, truss-lattice and cellular structures offering superior energy-absorbing capacity are implemented in crash box design. This work investigates the crushing behaviors and characteristics of square-tube crash boxes filled with truss-lattice and cellular structures with the objectives of lightweight design while improving the specific energy absorption and mean-crushing forces and lowering the initial peak crash force. The crushing efficiency of the crash boxes between four different types of structures: conventional, BCC, FCC, and Primitive-TPMS, are evaluated and compared using the nonlinear explicit dynamics finite element technique via LS-DYNA. The lattice and cellular structures perfectly show progressive deformation under impact with an excellent potential to absorb energy. The nodal equivalent technique is recommended for the model analyses for the crash boxes with filler structures. The fillers are shown to enhance the crashworthiness of the conventional crash box by controlling the whole deformation so that it remains progressive bucking failure. According to the analysis results, a crash box filled with Primitive-TPMS presents the highest crushing performance and this design is proposed for next-generation vehicles. [ABSTRACT FROM AUTHOR]