Investigations on welding distortion in an asymmetrical curved block by means of numerical simulation technology and experimental method

In shipbuilding, serious welding distortion often occurs especially in asymmetric curved blocks. Welding distortion not only reduces the fabrication accuracy of ship hull blocks but also decreases the productivity due to correction works. If welding distortion can be accurately predicted in a welded structure, the predictions will be helpful to effectively control the dimension accuracy both at the design stage and at the fabrication stage. In this study, both experimental method and numerical simulation technology were used to investigate the feature of welding distortion in an asymmetrical curved block. In the numerical simulation, a two-step computational procedure was used to analyze welding distortion in the asymmetrical curved block. At the first step, a thermal elastic plastic finite element method was used to compute the inherent deformations in several typical weld joints involved in the curved block. At the second step, an elastic finite element method based on inherent strain theory was employed to estimate the overall welding distortion of the whole model. Meanwhile, the effect of welding procedure on welding distortion was clarified by the proposed computational procedure. Moreover, the influence of each component of inherent deformations on twisting deformation in the asymmetrical curved block was examined numerically. Finally, the influence of principal orientation angle of the curved skin plate on twisting deformation was investigated by means of numerical simulation.