## Abstract

This paper presents the results of numerical and analytical studies to obtain ultimate strength enhancement coefficient (R
_{e}
) equations for external-ring-stiffened circular hollow section (CHS) X-joints under axial compression. The FE modeling approach is validated by the results of axial compressive experiments conducted in the authors’ previous research on six X-joints with and without stiffeners. In all, 160 unstiffened and ring-stiffened FE models of CHS X-joints subjected to brace axial compression were investigated. The effects of the brace-to-chord diameter ratio β the ratio of chord diameter to twice the chord wall thickness γ the stiffening ring width factor β
_{r}
(i.e. 2b
_{r}
/d
_{0}
where b
_{r}
is the ring width and d
_{0}
is the chord diameter), and the stiffening ring thickness factor τ
_{r}
(i.e. t
_{r}
/t
_{0}
where t
_{r}
is the stiffening ring thickness and t
_{0}
is the chord wall thickness) on the structural behavior of external-ring-stiffened CHS X-joints were evaluated. Parametric analysis showed that the ultimate strength enhancement coefficient R
_{e}
decreased with the increase in the diameter ratio between the brace and the chord β but once β exceeded 0.4, the effect on R
_{e}
was slight. Furthermore, the ratios of chord diameter to twice the chord wall thickness γ the stiffening ring width factor β
_{r}
, and the stiffening ring thickness factor τ
_{r}
were all positively correlated with improvement in the ultimate strength of the external-ring-stiffened CHS X-joints. An analytical formula based on the yield volume model was derived to predict the ultimate strength enhancement of external-ring-stiffened X-joints.

Original language | English |
---|---|

Pages (from-to) | 17-26 |

Number of pages | 10 |

Journal | Thin-Walled Structures |

Volume | 133 |

DOIs | |

Publication status | Published - 1 Dec 2018 |

## Keywords

- Axial compression
- CHS X-joint
- External stiffening ring
- Finite element method
- Parametric analysis
- Yield volume model