Flexural performance and failure mechanism of buckling-oriented honeycomb-filled tube subjected to three-point bending

Cellular solid-filled tubes subjected to bending loads tend to experience premature catastrophic collapse, primarily due to local buckling. To address this issue and improve the flexural performance of thin-walled tubes, a novel buckling-oriented honeycomb-filled tube (BOHFT) structure is developed. Three-point bending tests are conducted on BOHFT structures with additively manufactured buckling-oriented honeycomb (BOH) fillers, incorporating varying design parameters, including concave coefficient α , shape ratio β and segment number N . Results show significant improvements in bending strength and deformation stability of BOHFTs compared to traditional straight-walled honeycomb-filled tubes, with increases of 20.3% and 17.9% in mean crushing strength and crushing force efficiency, respectively. The buckling process and flexural properties of BOHFTs are primarily influenced by configuration parameters β and N , with a minor dependence on α . Moreover, validated numerical models are employed to explore the deformation mechanism, revealing that the arch-bridge effect of BOH under lateral compression enhances the interaction between the filler and tube walls, improving the global deformation and bending ductility of BOHFT. Finally, an optimized BOH filler design with effective length and gradient configuration design is proposed to further enhance the flexural performance and enhance the weight efficiency of BOHFTs.