Axial crushing theory of externally fiber-reinforced thin-walled twelve right-angle section tubes

•The crushing energy dissipation mechanism of metal TTRS tubes is presented.•The contribution of composite-metal wall is taken into account.•εd is presented to denote the effective crushing distance and the folding angle.•The expression of mean crushing force for fiber-reinforced TTRS tubes is derived.•The theoretical results are accurate when the fiber circumferentially wrapped.

This paper focuses on the crushing collapse theory of externally fiber-reinforced twelve right-angle section (TTRS) tubes based on the kinematic approach. This paper presents the crushing energy dissipation mechanism of metal TTRS tubes and derives the expression of mean crushing force. Considering the contribution of the composite-metal wall and the final crushing deformation, which affected by the accumulation of the composite after failure, the expression describing the mean crushing force for externally fiber-reinforced TTRS tubes is presented. The accuracy of the theoretical predictions is validated by finite element simulations, including four different metal wall thicknesses and three different amounts of composite plies. The results indicate that the mean crushing forces calculated by the proposed theory show a good consistency with the simulation results.