Static strength of collar plate reinforced CHS X-joints loaded by in-plane bending

This paper presents the collar plate reinforcement scheme to strengthen a Circular Hollow Section (CHS) X-joint, applicable for a fabricated joint which is subsequently found to be under-strength. The parametric numerical study on the static strength of collar plate reinforced X-joints loaded by in-plane bending is complementary to the study on doubler plate reinforced joints as reported in the companion paper. The load transferring mechanisms and failure modes of these reinforced joints are investigated and compared. From the range of geometric parameters investigated, the collar plate reinforcement is found to be more effective than its doubler plate counterpart to improve the static strength of the joints. Based on the numerical results, strength equations are established to estimate the static strength of collar plate reinforced X-joints.