Improving the fatigue reliability of metro vehicle bogie frame based on load spectrum

Abstract Fatigue cracks, which occur at the junctions between key brackets and the transverse beam of the metro bogie frame, significantly affect the operating safety of the vehicle. Since the load inputs in the design specifications used for bogie frame cannot fully address the actual operating conditions, it indicates that the fatigue reliability of bogie frames in actual operation is critically inadequate. In the event of this problem, a high-precision dynamometric frame was developed to conduct long-term on-track test to obtain real loading conditions and damage at the fatigue control locations. Taking the discrepancy between the measured fatigue damage and the calculated damage as the objective function, the damage consistency-based load spectrum was established and the damage of the frame under the operating condition was reproduced. Finally, fatigue reliability improvement of the bogie frame was systematically and comprehensively achieved.