Structural design and crashworthiness analysis of expanding-splitting circular tubes

The use of expanding-splitting circular tubes was proposed to improve crashworthiness and overcome their deficiencies in terms of low energy absorption and poor stroke efficiency in a single deformation mode. Quasi-static experiments and finite element simulations were conducted to study the force–displacement response of circular tubes under combined deformation modes. A theoretical model of the circular tube during expanding-splitting deformation was established to reveal the coupled expanding-splitting deformation and energy-absorbing mechanism of the circular tube. Furthermore, the factors influencing key parameters were analyzed using the finite element model. The results showed that the behavior changed smoothly from splitting deformation to curling deformation when adding preformed notches to the circular tube, and the final platform force of the circular tube decreased when increasing the transitional radius. Compared with the traditional expansive structure, the combined energy absorber offers better energy absorption with a 78% increase in platform force.