STRESS-ANALYSIS OF REINFORCED TUBULAR JOINTS SUBJECTED TO DIFFERENT LOAD TYPES

The reinforcing of tubular joints using doubler plates has been a common industrial practice as a last minute solution to resolve punching shear problems due to axial compression. However, such reinforcements may have negative effects when the joints are subject to different loading conditions. A parametric stress analysis of T reinforced welded round-to-round tubular joints subjected to axial tension and in-plane bending has been performed using the finite-element technique. Sixteen sets of geometric parameters were used for the parametric study by varying three parameters: doubler plate to chord thickness ratio t(p)/T; brace diameter to doubler plate length (width) ratio d/l(p); and brace to doubler plate thickness ratio t/t(p). The said study shows that t(p)/T and t/t(p) but not d/l(p) have significant effects on stress concentration factors in both load cases. The present results for T reinforced tubular joints are compared with those for the corresponding unreinforced joints obtained by the Authors and other researchers. In general, the reinforced joints are as good as the corresponding unreinforced joints in withstanding axial tension and in-plane bending, provided that certain criteria for the selection of doubler plates are adopted. Although out-of-plane bending is not considered in the present study, the influence of various geometric parameters are expected to show trends similar to those observed for axial tension and inplane bending.