Geometrical effect on the stress distribution along weld toe for tubular T- and K-joints under axial loading

This paper presents general remarks of the effect of the geometrical parameters on the stress distribution in the hot spot stress region for tubular T- and K-joints subjected to brace axial loading. As the stress distribution along the weld toe is very critical for the prediction of the fatigue life of steel tubular joints, the investigation of such geometrical effect can provide integrity assessment for tubular T- and K-joints. Previous research work was mostly focused on the study of the value of the peak stress, but ignored the stress distribution principle. Generally, the location of the hot spot stress along the weld toe affects the crack initiation. Accordingly, the stress distribution has critical effect on the propagating way of the fatigue crack. The stress distribution is mainly determined by the loading type and joint geometry. The geometrical effect on the stress distribution for tubular T- and K-joints subjected to axial loading has been investigated from both numerical and experimental methods in this study. Thereafter, a parametric study has also been carried out to investigate the effect of three popularly used joint geometrical parameters on the stress distribution. From parametric study, it has been found that chord thickness has remarkable effect on the stress distribution for both T- and K-joints, while brace thickness has no effect on such stress distribution. The last geometrical parameter, the diameter ratio between the brace and the chord, has different effects on the stress distribution for tubular T- and K-joints.