Chord pre-load effect on thick-walled CHS X-joints under moment loading

摘要

This paper reports the finite element (FE) study to investigate the chord stress effect on the static strength of moment loaded thick-walled Circular Hollow Section (CHS) X-joints. The FE results are compared to the calculated values using the CIDECT and ISO design recommendations. For compression-loaded chord, ISO recommendation is found to be more conservative than that of CIDECT for joints under in-plane bending (IPB) moment. For joints subjected to out-of-plane (OPB) moment, ISO recommendation is found to be un-conservative. For tension-loaded chord, significant strength reduction is observed for both types of loadings while both design recommendations ignore the effect of tensile chord load. A new chord stress function, with the geometric dependency incorporated, is proposed based on regression analysis of the FE results.