| With the continuous improvement of the operating speed of high-speed EMUs,the load environment of the on-board equipment during the operation cycle is constantly deteriorating,and the increased vibration between the components is likely to cause fatigue failure problems.The sand spreading device is used to guarantee the train in severe weather conditions and it is important to study the fatigue reliability of key components for smooth operation.This paper takes the high-speed EMU sanding device and the end of the frame as the research object.Through long-term follow-up test,study the law of vibration and stress changes in its actual application,and analyze the factors that affect the vibration and stress at the end of the sand spreader and frame.This paper studies its vibration and fatigue through simulation.The main research contents are:(1)Through long-term follow-up testing of the sanding device and the end of the frame,the trend of dynamic stress and acceleration is counted from the overall test period,and it is found that the large fluctuation of the equivalent stress amplitude is related to the operation line.(2)Through time-frequency analysis of the measured data,it is found that the vibration level from the end of the frame to the sand spreading device is gradually amplified.The overall vertical vibration level is higher,and the maximum vertical acceleration is 19.1g.There is a peak of double frequency energy in low frequency band and high frequency band in acceleration,and the main frequency of stress is 67.4 Hz.According to the time-frequency analysis results and the research results of the wheel-rail disturbance load,it is found that the energy doubling energy characteristics and peak frequency of the low frequency band are consistent with the vibration shock of the track plate,and the high frequency band is consistent with the vibration caused by the wheel polygon.(3)Study the influence of different working conditions on the vibration and stress level of the sanding device and the end of the frame.The research results show that the vibration level of the rear wheel decreases by 28% and the stress level drops by 35%.The vibration wheel improves the vibration and stress state of the structure to a certain extent.It was verified that the external load excitation that caused the vibration and excessive stress levels at the end of the sand spreader and frame was mainly the impact vibration of the track slab.The acceleration and deceleration conditions existed the vibration impact caused by the wheel polygon,but the energy was low.By comparingthe results of time-frequency analysis at different speed levels,it is found that the vibration and stress levels are significantly amplified when running along the river channel,which is caused by the impact vibration of the track slab.(4)Through the modal,harmonic response and quasi-static analysis of the sanding device and the end of the frame,the natural frequencies and vibration modes of each order are obtained.Combined with spectrum and simulation analysis,the results show that there is elastic resonance in the operation process.(5)In this paper,the frequency domain damage calculation method suitable for the measured data is selected.The damage assessment of each measuring point on the sanding device and the end of the frame is carried out and compared with the time domain method to verify the feasibility of the frequency domain calculation method.Random vibration fatigue analysis of the structure is carried out by means of simulation,and the fatigue life of the sanding device and the end of the frame is studied.67 pictures,8 tables,62 references... |
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