Building framework for selecting finite element models of complex large welded structure of railway vehicles

Finite element method (FEM) is an effective and popular tool for predicting the welding deformation and residual stress to help process optimization. But it is difficult to calculate welding deformation and residual stress without reasonable simplification, because the calculation is extremely time-consuming and difficult to converge. In this study, the inherent strain model (ISM), the large heat source model (LHM) and moving heat source model (MHM) are developed to simulate the welding deformations and residual stresses in a large welded structure of underframe. The simulation results from three models show that the underframe has obvious structural shrinkage and wide distribution range of the residual stress after welding. Calculation time indicates that ISM has the highest efficiency and it shows that MHM has the highest precision by comparing simulation results with experimental measurements. Finally, a simulation framework is proposed which will provide a reference for the selection of the finite element models for complex large welded structure in the future.