Research on Multi-axial Fatigue Strength Assessment of Railway Vehicle Bogie Frame

Railway vehicle structures endured multiaxial fatigue loads in the service process, which aroused many difficulties for bogie frame´s design and analysis. In this paper, firstly, the basic theory of multi-axial fatigue was explained. Secondly, the modeling methods of finite element analysis and stress state under standard loads were analyzed. Finally, three methods (maximum principal stress, Mises equivalent average stress and Sines average principal stress) were used to transform the multi-axial stress to uniaxial stress. The fatigue strength were evaluated and compared based on Goodman curves of ERRI B 12/RP 17 and JIS E4207 code recommended. It is concluded that maximum principal stress among the three methods is fit to analyze the multiaxial fatigue strength of bogie frame.