Metro Vehicle Bogie Abnormal Vibration and Fatigue Failure

Abstract

Objective Due to the increase of metro operation mileages and track conditions complexity, abnormal bogie vibrations caused by wheel-rail wear often occur. Bogie frame serves as an important load-bearing component, requiring research on its structural integrity and vibration failure mechanism under abnormal vibration conditions. Method Taking a metro bogie frame as example, based on vibration transmission tests and dynamic stress data, a study is conducted on the abnormal vibration and beam fatigue failure causes of metro vehicles on a line during operation, analyzing the source of disturbance and vibration transmission path. Based on the results of frame working modal tests, the vibration acceleration and dynamic stress time-frequency characteristics at beam failure points when vehicle passing typical sections are analyzed. By analyzing influencing factors such as wheel polygon, rail corrugation, and vehicle operating speed, the amplitude and spectrum characteristics of beam dynamic stress are investigated. Result & Conclusion Before wheel reprofiling, the main measuring points where equivalent stress amplitude exceeds the limit are concentrated at the connections between beams and side beams, beams and small longitudinal beams, and the upper cable supports of beams. After wheel reprofiling, the equivalent stress amplitudes at all measuring points significantly decrease, far below the allowable stress amplitude. The main external excitation source causing beam cracking is the 5 to 8 order wheel polygon, and the exacerbated vehicle vibration caused by wheel off-roundness is the direct cause for fatigue failure of beam cable supports.

Keywords

• metro
• vehicle
• modal vibration
• fatigue failure