Research on stress concentration factor of tube joints under pure bending and torsion loading

For fatigue strength design and evaluation as well as for multiaxial fatigue tests analysis of welded structures, the stress concentration factor (SCF) at the weld must be known. In the present study, two common models of multiaxial fatigue tests, tube-plate (TP) model and tube-tube (TT) model are selected as the research objects. SCFs of the two models with various geometric parameters under pure bending and pure torsion loading have been investigated by conducting a series of three-dimensional (3D) finite element models based on linear elasticity theory. The effect of weld width (w), plate thickness (t), weld toe notch radius(r), and reinforcement angle (θ) on SCF is assessed. The quadratic parametric equations based on t/r are proposed to predict SCFs of the two models, which reveal satisfactory accuracy.