Methodology for assessment of material fatigue in the area of welded joints of railway bogies by calculation

The current work presents the problem of assessment of the material fatigue in the welding area of the rail bogie frame type Y25LS-K. During the assessment process of the bogie frame dynamic strength, it was found that the results from the theoretical assessment differ from the experimental ones. An analysis of the reasons for these differences was made. A few approaches for the theoretical assessment are presented in order to match the conditions for application of the prescribed loads in calculations as close as possible to the test conditions. Proposed methodology allows the commissioning of bogies into service only based on a theoretical assessment of material fatigue in the welding areas of the bogie frames. The methodology is verified in real theoretical and experimental studies of the certified design of bogie Y25LS-K, produced by Transvagon AD, Burgas. The methodology can be used by researchers, performing a stress-strain analysis of the bogie frame as well as by the notified bodies responsible for the admission of those products into service. (paper)