Finite Element Analysis On Residual Stress Of Welding Assembly For I-beam And End-plate

In recent years, with the development of numerical calculation methods and computer technology, numerical simulation for welding residual stress has been developed. But the study focusing on welding residual stress for large and complex structure is limited, due to the complexity of the welding process and restriction of computing capacity. The welding assembly of I-beam and end-plate is a widely used node form in steel structures. But for the three-dimensional (3D) finite element analysis on welding process for such complex and large welded structure, it is very difficult to build3D physical model and divide finite element mesh. In addition, the calculation is time-consuming. These reasons limited the numerical simulation study for this type of welded structure. Research work on3D finite element analysis of welding residual stress for I-beam and end-plate welding assembly has not been reported until now.In this paper, welding assembly of I-beam and end-plate with medium plate was taken as the research model, moving body heat source model was adopted based on the birth-death technique, welding temperature field and residual stress were calculated via parametric design language of ANSYS software, and the simulation results were analyzed. Parameters used in the simulation process such as reference temperature, welding current, arc voltage, welding speed and size of weld section were obtained by experimental method. Infrared thermometers were employed to measure temperatures of test points on the weld seams, the fusion line of the weld cross-section was observed and measured to verify the validity of simulation results. The hole-drilling method was adopted to determine residual stress for verification purpose. Simulation and experimental results of temperature field are in good agreement, simulation and measurement results of welding residual stress distribution trend are roughly the same, prove that in this paper the3D finite element analysis method is feasible and the data are reliable. The results of this study provide support for practical application and simulation research on welding temperature field and stress field of large and complex structure.According to the difficulty for numerical simulation on full-scale model of large and complex welded structure, three kinds of simplified algorithm were proposed, namely split method, simplified method for symmetrical structure and simplified method for structure with long-distance welds. The influence of the size and boundary constraint conditions of the split model on the simulation results of welding residual stress were studied. These simplified methods provide a novel approach for quantitative calculation and analysis of welding residual stress for large and complex steel structure, and can significantly improve computational efficiency.This paper also studied the effect of welding sequence on welding residual stress. The results show that the change of the welding sequence has a significant influence on the distribution pattern of the stress, but has little influence on the peak value of welding residual stress. This conclusion provides a theoretical basis for the reasonable welding process design.In summary, the study of this paper provides basic reference for research of finite elememt simulation applied in welding process design, structure optimization of large and complex welded structure. It has important theoretical significance and practical engineering value.