Prediction of stress concentration factor distribution for multi-planar tubular DT-joints under axial loads

The stress concentration factor (SCF) plays an important role in the fatigue life assessment of tubular joints. Although various SCF parametric equations have been proposed for uni-planar tubular joints, only few are focused on multi-planar tubular joints. In the present study, the finite element (FE) method was employed to investigate the SCF distributions along the chord-brace intersection of multi-planar DT-joints. A method of sub-zone mesh generation was developed to ensure good quality and an appropriate number of FE meshes. The effects of the geometrical parameters on the SCF distributions were investigated. A set of equations was proposed based on the results of the FE analysis. Two types of error analysis were used to verify the reliability of developed equations.