Fatigue Failure Mechanism and Improvement Method of Safety Hanging Seat for Speed-up Passenger Car Bogies

Abstract

Analyzed the fatigue crack characteristics near the safety lifting seat hole of the speed-up passenger car bogie,proposed the hypothesis that structural vibration fatigue caused by resonance phenomenon is the most important cause of crack in this part. through finite element simulation, the front 1-10 order mode shape,analyzed the measured acceleration and dynamic stress tests of each order mode frequency on the line.Obtains Equivalent Stress,Acceleration and Its Main Frequency ,and carries out comparative analysis with finite element simulation results. Based on mastering the failure mechanism of safety hanger.Optimize the structure of safety hanger and its fixing mode through structural improvement and adjustment of connection mode, and carry out line test on new structure,and evaluate its safety and economy.The research results show that:is affected by normal bus line conditions,safety boom vibration frequency(acceleration main frequency is 91.78Hz Main frequency of dynamic stress 91.00Hz and 4 Mode Frequency of Order(95.Calculated by Finite Element Method 79Hz.)The power spectral density of longitudinal acceleration of the safety boom which is close to each other and generates resonance is much larger than its transverse value and vertical value,which is consistent with the running direction of the train.Therefore,Vibration fatigue causes cracks to be generated at the edge of the safety suspension seat hole and 5mmthick gasket,is added on both sides of the bolt hole, and the safety boom is changed from a steel plate bending structure to a steel wire rope flexible structure.The equivalent stress amplitude at the bolt hole can be reduced to the greatest extent,and the fatigue damage accumulation is reduced. The improved safety boom meets 120010,000 kilometer usage requirement,and achieves better economic effect.