Study on FEM Numerical Simulation Method for the Welding Distortion

Abstract

The control of welding distortion during assembly process is very important. At present, there are mainly two numerical simulation methods for the welding distortion which are thermo-elastic-plastic finite element method and its simplified approach of inherent strains. At first, taking T-joint as an example, the welding distortions were computed using two methods mentioned above. Based on thermo-elastic-plastic finite element method, welding process was simulated by life and death element, moving heat source and transient state thermal field etc. Then, the welding distortion was calculated by inherent strains method after thermo-elastic-plastic computation. It was concluded from the comparison that the simulation results by using the two methods are consistent. Therefore, the inherent strains method can be conveniently and economically applied to prediction of structural welding distortion in engineering. Applied the inherent strains method, welding deformation was predicted for the bogie frame side beam of high speed train. According to the deformation results from the finite element analysis, the welding deformation of the bogie frame side beam was lager than the tolerance of quality and in reasonable agreement with the experimentally determined distortion values. The work in this paper indicated that the inherent strains method was effective to predict the welding deformation so as to control the welding quality in large complex structures, such as the bogie frame of railway vehicle. Key words: welding distortion; thermo-elastic-plastic method; inherent strains approach; numerical simulation; bogie frame;