Research And Application Analysis Of Axle Load Spectrum Of 250km/h EMU

The axle is one of the key components of high-speed trains.With the rapid development of high-speed trains in China,people have put forward higher requirements for the service life and fatigue strength of axles,that is,it is necessary to study and analyze the force of the axle when it is running under actual line conditions.In this paper,the CRH2A EMU axle is taken as the research object.Based on the line test data and finite element simulation,the axle load spectrum is studied and applied.The specific research contents are as follows:(1)Development of force wheel pair:Complete the establishment of the axle simulation model.The vertical and lateral loads of the model are simulated.According to the finite element results,the wheel stress distribution characteristics are used to reasonably determine the vertical and lateral load identification points and the positions of the axle sections.The fatigue strength and static strength of the wheel after punching were evaluated by standard and the production of the force wheel pair was completed.(2)Acquisition of load transfer coefficient and processing of measured data of the line:The static calibration test method is designed,and the static calibration data under different working conditions is processed and analyzed to obtain the transfer coefficient of the vertical and lateral loads of the axle.The measured data of the line is processed,and the time history of the axle load is obtained by combining the load transfer coefficient.The gyroscope signals are used to distinguish different working conditions such as straight line and curve,and the load distribution characteristics under different working conditions are analyzed,and the load spectrum under each working condition is compiled.(3)The fitting extrapolation study of the measured load spectrum:The fitting and extrapolation estimation of the measured load spectrum is carried out by the kernel density method.The fitting effect under the two methods of fixed bandwidth and adaptive bandwidth is compared based on the goodness of fit and the angle of damage.By analyzing the extreme values under different extrapolation multiples and the fitting error of the damage,the fitting extrapolation method which is more suitable for the high-speed axle load spectrum is determined.(4)Axle fatigue strength check and residual life analysis:Based on the measured stress spectrum and the extended life stress spectrum obtained by fitting extrapolation,the fatigue strength and remaining life of the dangerous section of the measured axle are analyzed.The equivalent load is calculated based on the extended load spectrum.The stress at the wheel seat that cannot be tested is obtained by finite element simulation,and the fatigue strength and life analysis at the wheel seat are analyzed to predict the part where fatigue failure may occur.