Development and Simulation of Isotropic Hardening for AISI 1035 Weld Stress Prediction during Design and Welding Assembly of Lower Brackets of Rail Cars

摘要

Residual stresses through plastic deformation during the assembly operation of a rail car can cause cracks, distortion or other associated welding flaws if not checked. This study considers the use of analytical and numerical methods involving the simulation of isotropic hardening models for the prediction of AISI 1035 weld residual stresses during the arc welding assembly of the lower brackets of a rail car. Using the isotropic hardening model as well as the ABAQUS simulation software, the dynamic simulation of the gas metal arc welding process was performed at ambient temperature of 25°C over varying temperatures. The thermal modelling of the weld pass was carried out followed by the determination of the stress and strain values from the combined thermal elastic-plastic analysis. The results obtained indicated that the predictive ability of the isotropic model is highly significant, with the values of the weld stress and corresponding strain agreeing closely with the experimental values over varying ranges of temperatures. Hence, the isotropic hardening model can be used for weld residual stress simulation and prediction. Future work can consider the combination of both the isotropic and kinematic models.