Evaluation of Geometrical Effect on Stress Distribution for Tubular T-Joints under Axial Load

Abstract

For tubular T-joints subjected to axial load, the stress distribution along the weld toe can be predicted by some reported parametric equations in the literature. Conventional method indicates that the hot spot stress along the weld toe for tubular T-joints subjected to axial load is located at the saddle position. This conclusion is reliable when the thickness of the chord member of a tubular T-joint is relatively small. Alternatively, the hot spot stress is always fixed at the saddle position, when the geometrical parameter 7 (chord radius/chord thickness) is limited in a common range (12 ≤ γ ≤ 30) specified by CIDECT (2000). However, it is uncertain if this conclusion is still correct when the parameter γ is smaller than the above-specified range. In this study, the effect of geometrical parameters on the stress distribution for tubular T-joints subjected to axial load has been studied. First, a finite element method to model welded T-joints has been proposed, and the accuracy of this method to analyse the stress distribution along the weld toe of tubular T-joints has been verified by comparing numerical results with experimental results. Thereafter, 140 models of T-joints with different geometrical parameters have been analysed using finite element method. From the investigation on the numerical results, it has been found that the location of the hot spot stress along the weld toe is shifting between the crown and the saddle when the parameter γ varies. Thus, caution should be taken in practical engineering design when it is necessary to estimate the approximate position of the peak stress for tubular T-joints under axial load.