Study On Inherent Strain In Steel Box Girder

Welding technology occupies a very important position in industrial production of China. The welding residual stress and deformation have bad influence to the production of bridge and its service life. Predicting and reducing the welding deformation is of importance in the welding engineering research which need further address. There are two problems must be resolved in predicting welding deformation of large and complicated welded structures. One is how to ensure enough deformation accuracy, the other is how to save calculation time and cost.The paper based on the actual steel box girder construction, analyzes the current theories of predicting the welding deformation, chooses the inherent strain method as a main research approach and the thermo-elastic-plastic finite element method as a checking method, utilizes the finite element analysis software ANSYS, to get the inherent strain's value and the distribution of welding deformation in the steel box girder construction.First of all, the paper simulates the dynamic temperature field with a three-dimensional model, and considers the material nonlinearity, geometric nonlinearity and contact nonlinearity to obtain more accurate simulation results. Second, the paper based on the thermo-elastic-plastic finite element method, considers some factors'impact on the inherent strain, such as Floor plan dimensions, floor thickness, welding speed and weld size. Finally, with the optimal welding parameters, by simulating the different thickness of steel box girder, the paper analyzes the relationship between the inherent strain and the thickness of the quantitative. Before predicting the welding deformation in use of the inherent strain method, the paper verifies the feasibility of utilizing inherent strain method in the production of steel box girder. According to the results of the welding technology test and welding deformation test, and using the inherent strain method, the welding deformation calculation is in line with the actual project. The analysis shows that the finite element method based on the inherent strain can predict the welding deformation of large and complicated welded structures better, and can be used as a strong technical support in the future actual production to control welding deformation.