Geometrical effect on SCF distribution in uni-planar tubular DKT-joints under axial loads

Despite the frequent use of DKT-joints in offshore structures, no parametric equation is available for determining the distribution of stress concentration factors (SCFs) along the brace-to-chord intersection of this type of tubular joints. In the present paper, the effect of non-dimensional geometrical parameters and brace-to-chord inclination angle on the distribution of SCFs and DKT-/KT-joint SCF ratios (SRs) along the weld toe of tubular DKT-joints under the balanced axial loads is studied. Thereafter, a parametric equation is proposed for predicting the distribution of SCFs along the 360° spatial curve of the weld toe. The proposed equation satisfies the acceptance criteria recommended by the UK Department of Energy (DoE), and consequently can reliably be used for design purposes.

► Effect of geometrical parameters on weld toe SCF distribution in tubular DKT-joints was studied.
► A parametric equation was proposed to determine SCF distribution along the weld toe.
► This is the first formula developed to predict weld toe SCF distribution in DKT-joints.
► SCF distribution and location of HSS are both dependent on geometrical parameters.
► The HSS may not be always located at either saddle or crown positions.