| In response to the call of railway speed increase,the increase of train speed is inevitable,which will lead to the complexity of the force between wheel and rail,and the worse the function of wheel axle.The wheel-rail load is closely related to the safety and reliability of the high-speed rail transit system,and its distribution characteristics can provide theoretical support for the subsequent structural strength evaluation and life evaluation.In this paper,the wheel-rail load of domestic standard EMUs are taken as the research object.The force-measuring wheelsets were made by using the continuous measurement method.The calibration tests and the actual line tests were completed on the Daxi line.Then the model of whole vehicle was established by using simulation software,and the theoretical line tests of line between Beijing and Tianjin and line between Wuhan and Guangzhou line were completed.The data of different wheel-rail force time history obtained were processed respectively.Sampling and statistics were carried out for different working conditions such as different speed grades,line section,each round trip,etc.64 level time-domain load value spectrum,peak valley load spectrum and amplitude load spectrum were prepared,and the change trend and reason were analyzed:(1)Time domain aspect: under the condition of straight line,the wheel-rail vertical load is generally normal distribution,and the fluctuation center is the static wheel weight value.The distribution of wheel-rail lateral load has two peaks,which fluctuate around 0 k N.Under curvilinear condition,the vertical load deviates and the transverse load increases while the increasing degree is different.Frequency domain aspect: the main power spectral density components of wheel-rail vertical load and lateral load are mainly distributed within 100 Hz,and the energy "spikes" corresponding to low speed level and high speed level are different.(2)The peak valley value spectrum and the load value spectrum are basically the same.The difference is that the frequency of the peak valley value spectrum is reduced by about 100 times,and the regularity is more obvious.The wheel-rail amplitude load spectrum focuses more on the fluctuation of data.(3)The running speed,curve radius,vehicle load and line condition of the train will have certain influence on the wheel-rail force.The higher the speed is,the moreviolent the fluctuation degree of wheel-rail vertical force and lateral force is,and the wider the distribution range is.In the process of passing the curve,the larger the radius of the curve and the smoother the line,the smaller the difference between the train running speed and the balance speed,and the smaller the deviation of the wheel rail force fluctuation center.The larger the vehicle load,the more obvious the degree of wheel-rail vertical force deflection,but the lateral force has little influence.The train up and down working conditions have almost no effect on the wheel rail force.Although the specific values of wheel-rail force of different lines may be different,the distribution rule is roughly the same.(4)The rigid flexible coupling dynamic model of the whole vehicle was established by SIMPACK dynamic simulation software,and the excitation spectra of line between Beijing and Tianjin and line between Wuhan and Guangzhou were imported respectively.The corresponding wheel-rail force load spectrum and acceleration spectrum were obtained,and the degree of line excitation was compared and analyzed.In theory,the vertical force and acceleration under the excitation of Wuhan-Guangzhou railway are greater than that of Beijing-Tianjin Railway set up in the same route.The lateral effect is the opposite,but the difference between them is not obvious.The measured results of Daxi line are larger than those of the two theoretical lines in both vertical and lateral actions.79pictures,14 tables,66references. |
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