Fatigue strength analysis of a welded railway vehicle structure by different methods

The endurance limit approach with maximum amplitude loading (constant loading amplitude) and the cumulative damage approach with variable amplitude loading are both established methods for the fatigue assessment of the bogie frame of a rolling stock. These methods are presented for the vertical main loading of a bogie frame for a light rail vehicle. Assessments are carried out for the normative load requirements according to the relevant standard EN 13749 [1] and also for a vertical force range spectrum deriving from a multiple body system simulation of this railway vehicle. The multiple body system simulation supplies more realistic loads depending on the actual railway application conditions. These different fatigue assessments allow a comparison of the normative load requirements with realistic load assumptions.In general the stress analysis is based on the nominal stress approach. Additionally, for the area subject to the maximum stress, a notch stress analysis is carried out. The comparison of stress analyses for some selected stress points shows the potential and the advantages of the fatigue assessment with the real loading assumptions and with different evaluation methods.