Numerical Analysis Of Welding Temperature Field And Stress Field Of Steel Box Girder Manufacturing

With the continuous development and maturity of China's machinery welding processing technology, the steel box girder welding processing and manufacturing technology has been rapid developed. The steel box girder which has the advantages of light weight, large capacity, convenient construction and manufacture, and the good integrity, has widely used in various interchange bridges and viaducts in roads and bridges of the urban civil engineering. The welded joints which are important components of the welding assemblies have great influence in the property of the welding assemblies. The main reason is that the welding residual stress will formed in the welding assemblies after welding. The welding residual stress and residual deformation in a certain environment will seriously affect the weldments fatigue strength, anti-corrosion and anti-high temperature creep ability. The welding residual stress and residual deformation are very complex; they are difficult to handle only by theoretical analysis. So in practical engineering they usually combine the theoretical analysis and numerical analysis, and compare with the experimental data to predict the change rule of the welding residual stress and residual deformation.This paper is used the Second Ring Road, Chengdu City renovation project of the steel box girder manufacturing as the research background. Through the numerical simulation of steel box girder welding process by the finite element method, analysis the welding residual stress and residual deformation in the welding process of steel box girder and explore the influencing factors, providing reference for the manufacture of steel box girder. The research contents of this paper are as follows:1. Discusses the produced reason and influencing factors of the welding residual stress, and discuss its influence to welding assemblies.2. Discusses the theoretical basis for the analysis of numerical simulation of welding process, and combined with the software of ANSYS to establish the model of numerical simulation of the process of welding, to set the boundary conditions, to select of heat source, material nonlinearity and loading solution processing, which can give detailed analysis of those problems.3. Using ANSYS finite element analysis software, implement the numerical simulation under the two heat source models in the seventh welding structure in the steel box girder of the Second Ring Road. Chengdu City renovation project. By compared with the results of other related literature that the welding temperature field and stress field numerical simulation results is correct.4. Using the Second Ring Road, Chengdu, steel box girder welding structure numerical simulation examples, to study the plate thickness and Gauss heat source effective heating radius and weld opening angle and weld penetration rate, these four parameters affect the results of welding numerical simulation calculating. Among them, under the three parameters of the plate thickness, weld opening angle and weld penetration rate, the plate's maximum temperature values increased with the increase of parameters, which conforms to the physical law of welding, only the magnitude of changes in the parameters is slightly different. Under the influence of the parameters of the Gaussian heat source radius, the plate's maximum temperature first increases and then decreases and tends to level.