Simulation Study Of Residual Stress And Distortion Of Welding Bogie Frame In Speeding Up Freight

Bogie frame is a critical part to bogie to burden all kinds of loads from wheels and rails, it is a cadre of assembling other parts as well. To be up to the mustard, more and more demands for stiffness and precision of manufacture are brought forward. The problem of distortion residual stresses and reduced strength of a structure in and around a welded joint in manufacturing process of welding bogie frame is important issues in the railway industry.Analysis of numerical simulation in welding is a complex technology including lots of fields. In welding process of complex structure, welding path is used which make self-programmed subroutine more difficult to accord with numerical simulation. The weld fillet and adaptive meshing are also involved in 3D numerical simulation. In order to solve above mentioned problems, special user subroutines in Fortran are completed to simulate: the moving heat source during welding used transform.for and flux.for; the weld fillet is simulated by active/deactive technique used uactive.for; the implement of adaptive meshing in 3D numerical simulation used fordctfor.The objective of this thesis is to develop and evaluate a method for introducing a moving heat source into a FE-model. The heat source should be able to move along any general 3D curve. The aim is to facilitate the simulation of welding for complex weld paths and geometries. The above techniques combined with analysis of thermal elastic plastic behavior of metals by finite element method are used to analysis welding bogie frame process of typical joints. Because of the complexities of the studied problems, only welding process of the typical joints can be simulated under the conditions of the current hardware. The welding process of total bogie frame will be simulated effectively with better hardware provided. Based on the theory of welding shrinking force and MSC.Marc software of finite element together, welding deformation is predicted not only for the total bogie frame but also for each beam in frame of this dynamical bogie. According to the all deformation results from finite element analysis, the appropriate pre-deformation and the appropriate welding parameters are selected so that the minimum welding deformation and good welding quality are finally obtained. All done in this study indicates that the new method presented in this paper is effective to reduce welding deformation and control welding quality for the frame of dynamical bogie.