2019 年 37 巻 4 号 p. 141-151
In the fabrication of steel structures, welding is widely utilized to join the materials. Due to the welding, distortions are inevitably generated, and these distortions may cause problems in accuracy or labor costs. In this research, to establish an analysis method which can predict the welding distortions in complex large-scale structures, we proposed a new analysis method based on the Idealized Explicit FEM. In the proposed method, an algebraic multigrid method was introduced to the Idealized Explicit FEM to achieve an efficient analysis in realistic structures. The proposed method was applied to the prediction of the welding distortion in the base structures of the construction machine. The number of welding passes was 28. The predicted and measured distortions were compared. As a result, it was demonstrated that the proposed method has a high analysis accuracy. The analysis finished within the realistic time within 35 hours. The influence of welding sequence on the deformation was also investigated by changing welding sequence. The result indicated that the welding sequence may have considerable effect on the welding distortion and is necessary to be investigated in advance of the production.