Identification causes of cracking on the underframe of wagon for containers transportation – Fatigue strength assessment of wagon welded joints

This paper describes a methodology used to identify causes of cracking nearby the welded joint on the underframe of wagon type Sgmns for the transportation of containers and swap bodies. Because of complex mounting, bending and welding technology of underframe bottom part, it was not possible to solve this problem with a commercial software. The aim of this analysis is to identify and register the residual stresses that appear after the process of mounting of the underframe bottom part. According to the TSI standard and norm EN 12663:2000, the fatigue strength analysis of Sgmns wagon for containers transportation was done. The analysis was done to discover kind of loads which induce cracks in the welded joints. The obtained results for the case of maximum vertical load were shown. The analysis of obtained results identified that cause of cracking on the bottom part of underframe of wagon type Sgmns is fatigue.