Modelling of residual stresses in a narrow-gap welding of ultra-thick curved steel mockup

A plane strain model, an axisymmetric model and a lumped-pass three-dimensional (3D) model were employed to simulate the residual stresses in a narrow-gap welding 300 mm-thick curved steel mockup. The lumped-pass 3D model was built with the lumping scheme based on the two-dimensional (2D) temperature field result. The residual stresses on the top surface of the mockup were measured using the hole-drilling method and compared with the simulated stresses. Results show that the plane strain model cannot capture the asymmetric conditions of the curved mockup; the through-thickness transverse stress within the weld zone presents a self-equilibrated distribution, and the through-thickness hoop stress within the weld zone are almost tensile with the peak value occurring at a certain depth (8 mm) beneath the top and bottom surfaces.