Numerical analysis of welding deformation and residual stress in marine propeller nozzle with hybrid laser-arc girth welds

Highlights: • Heat source combined of Gaussian surface with the cone was proposed to simulate thermal flux of laser power and arc power. • Welding deformation and residual stress of T-joint was predicted by TEP-FEM with 3D/SHELL element. • Welding deformation of marine propeller nozzle was predicted by the local-global mapping method. - Abstract: Deformation and residual stress of the large marine propeller nozzle in hybrid laser-arc girth welding were studied. Welding distortion and residual stress of the basic T-joint were firstly analyzed by thermal-elastic-plastic finite element method and verified by experiment. Combination form of the Gaussian surface heat source model and the conical heat source model was proposed to simulate the thermal flux of laser and arc power at the weld zone. The prediction errors of the width and penetration of the weld profile were respectively 5.26% and 5.89%. For angular distortion, experiment results have a good consistent with simulation results. An obviously gradient of the longitudinal stress and transverse stress was appeared at interface zone of flange and web. An optimal welding sequence was then obtained by analyzing welding deformation and equivalent residual stress. Based on the local-global mapping method, welding deformation of the marine propeller nozzle was further predicted by loading plastic strain sourced from local model.