Structural analysis of Y25 type bogie body using finite element method and investigation of fatigue in welding seams

Bojies are mechanical systems consisting of multiple assembly parts that are used to carry vehicles used in rail systems today. Examples of these assembly parts are bojie suspension systems, wheel sets, brake systems and axle boxes. It has become an important situation to design the bojie body that carries vehicles used in rail systems within safe safety limits. Thanks to railway transportation, it is possible to carry serious loads in one go. For this reason, bojie bodies need to be designed as lightweight in order to increase their carrying capacity. In order not to disrupt railway network traffic and to eliminate cost losses caused by delays, it is desired that the load transfer times do not last longer than necessary. For these reasons, it is desired that there are no structural problems on bojie bodies. The main structures in bojie main bodies are manufactured by welded junctions. For this reason, crack formation in welded seam areas will create serious problems in terms of the overall assembly. Within the scope of this thesis, the structural analyzes of the Y25 bojie body were verified with tests and the effect of stresses in welded seams were examined. The static loading tests of the bojie body were carried out in the test laboratories of VZU Plzen, accredited by the Czech Accreditation Institute. The test loads to be applied on the bojie body were determined by reference to the EN 13749 standard. Each test load was numbered to prevent possible confusion. Single-axis and three-axis strain gauges were attached to the designated areas on the bojie body. After the test, the stresses in the strain gauge areas were calculated and verified with the Ansys Workbench FE software. Limit CAE software was used to evaluate the results in the welded seams. The stress results were transferred from the Ansys Workbench analysis program to the Limit CAE software. The results in the welded seam areas were evaluated according to the DVS 1612 standard and interpreted according to the EN 15085-3 standard. The results were found to meet the requirements.