Stress spectrum compilation method and residual life prediction for hot spot position of metro bogie frame under resonance condition

Abstract

Metro bogie frames occasionally suffer from fatigue failure during the operation. Through fatigue fractography, it is determined that the fusion defect of the weld root at the frame’s hot spot is the internal cause of fatigue failure. According to the field test, the modal frequency of the frame coincides with the wheel-rail coupling vibration frequency when running under some specific track structures, which is the external cause of the frame’s fatigue failure. In addition, the wheel out-of-roundness (OOR) and the curved track with a radius below 600 m significantly affect the fatigue life. Based on this, the tailoring principle of the stress spectrum is studied and the whole life cycle stress spectrum is compiled. Finally, the residual life of the frame evaluated by the damage tolerance method is 1.208 × 105 km. The evaluation of the residual life provides a reference for optimizing the maintenance strategy of the bogie frame.