Fatigue strength of laser beam welded thin steel structures under multiaxial loading

The multiaxial fatigue behaviour of thin laser beam welded tube–tube specimens of the structural steel St35 was assessed according to the methodology of the fictitious weld root radius of rf=0.05 mm and the application of the Effective Equivalent Stress Hypothesis (EESH), especially considering the fatigue life reducing influence of out-of-phase loading in comparison to in-phase loading. The results are applicable for the fatigue design of laser beam welded car body and chassis structures of thin steel sheets (t<3 mm).