Fatigue life estimation of welded connections in a tram vehicle

Low floor tram vehicles are becoming popular for mass transportation due to their versatility. Most of the body of trams is composed of welded structures which are prone to fatigue failure. In this study, the fatigue life of welded joints on a low-floor tram is investigated using the hot-spot stress and structural stress methods. To assess the suitability of shell elements in finite element models for fatigue analysis, we performed hot-spot stress calculations for three benchmark cases. The hot-spot stress computed using the shell element models is comparable to the results obtained from a solid model for most loading cases. Based on these findings, the fatigue life of four critical regions in a tram are estimated using the hot-spot stress and structural stress methods. It is found that the fatigue lives computed using the structural stress method are more conservative than the fatigue life results obtained from the hot-spot stress method.