Numerical Simulation Of Residual Stress For Side Beam Of Welding Frame

As the main component of locomotive, bogie plays a vital role for traffic safety. And the bogie frame, which is welded by box beam, is the main carrying and transferring power part of bogie. As there is inevitably residual stress in the welding process, the framework will crack or even craze, it will give rise to many potential safety problems. Commonly used method to reduce or eliminate the residual stress of welding is to have heat treatment or mechanical treatment after the welding. However, without predictive analysis, there is great uncertainty of the elimination effect. Therefore, through the prediction, measurement, and analysis of welding residual stress, and according to its cause and existence rule, we can take corresponding measures to reduce residual stress and improve the distribution characteristics, which has an important project practical value for improving the carrying capacity of welded structure and to extend its service life.The paper analyses the characteristics of numerical simulation about welding residual stress as well as the status and progress of welding stress research both at home and abroad. Finite element numerical analysis attracts the attention of more and more researchers because it is seldom limited by the geometry of objects, and boundary conditions and physical characteristics, and also because it is very practical and flexible etc. However, it is not widely used in welding yet. Therefore, mathematical models and finite element method for welding temperature field and stress field are given in this paper on the basis of finite analysis theory. And with the finite element analysis software ANSYS, on the basis of elastic-plastic method, the paper makes numerical simulation of the temperature field, dynamic stress and welding residual stress for the T-shape welded joints and box beam structure. Aiming at the problems that there are lots of calculations for the welding residual stress simulation of the side beam of welding bogie frame, and it is difficult to determine the time step, and the results are difficult to converge, the author of the paper researched element, mesh, time step and boundary conditions, and use regular shaped 3D solid hexahedron element without middle node to mesh, and refine in the near heat region and sparse in the far heat region, which enhances the calculating efficiency. It is difficult to simulate heat source and the filling process of the metal, the paper gets the results that match with the classical theory by using the birth-death element method to simulate the metal filling process. The paper also gets the evolvement of the welding temperature field, heat stress field and residual stress of the T-shape welded joints and box beam structure by Gauss Heat source model, and by APDL program to simulate the heat source movement, which provides evidence for the feasibility study of the numerical simulation of complex welding structure.The factors impacting the residual stress of box beam are numerous, among which the important one is the welding sequence. Through the consult of the method of T-shape welded joints finite element modeling, and interchanging of local coordinate which is established, the paper simulate the box beam welding under four different order, and gets the distribution of the welding residual stresses and permanent deformation. The paper has certain practical value for it provides important data for the control of welding residual stress and optimization of welding order.