Dynamics And Load Analysis Of High-speed Trains Considering Stochastic Factors

With the rapid operation technology of high speed EMU in China,the running speed is increasing and the stability is constantly optimized.However,there are still a lot of problems in the operation of the EMU.There is a low frequency sloshing phenomenon in a variety of emu after turning repair,and the lateral acceleration of the wheel in the middle and later stages of the wheel wear is over the alarm;the mechanism and the bifurcation of the serpentine destabilization form are different in different wheel rail wear conditions;the rail grinding profile of different lines is inconsistent,and the contact relationship between the wheel and rail when the train is running across the line changes.The smoothness,stability and safety of high-speed EMU should be taken seriously.Dynamic simulation is one of the best means to simulate train actual operation.Load spectrum is the basis for theoretical analysis and full-scale structural fatigue test of high-speed trains.On the basis of SIMPACK,the random factors of wheel rail geometry and interface parameters,wheel rail matching,vehicle suspension parameters,track irregularity distribution and other factors are combined through Latin hypercube sampling are considered.On the basis of the simulation data,the load variation in the high speed train operation is studied,and the statistical laws of load spectrum,load spectrum and random factor,load spectrum and dynamic performance are obtained.The main results are as follows:1)In this paper,dynamic simulation software SIMPACK is used to establish a simulation model of a high speed EMU trailer,and the dynamic model is verified compared with the measured data.The variation range and mean value of stationarity index are basically consistent with the long-term test results on the line,and the average value is close to that of the bench test.Therefore,this modeling is more reliable.2)By dynamic simulation,the relationship between the dynamic performance of a EMU and the random factors is obtained.Among them,the comfort index of empty cars and heavy vehicles exceeds 2 with a ratio between 1% and 3%.Most of the safety index values are small,and the safety indexes are far less than the safety limits specified by the standard,and the stability is also good.When the lateral stability index exceeds when the car runs faster than 330km/h.The equivalent taper does not necessarily change monotonically with the gauge or the bottom slope of the rail.The average and maximum values of transverse force and the lateral acceleration are increased with the equivalent taper.When the mileage is greater than 100 thousand km,the maximum of comfort index increases with the increase of mileage.Vehicle suspension is mainly affected by temperature factors.The lateral force,frame acceleration,stationarity index and comfort index increase rapidly with the track spectrum amplitude.In addition,the statistical regularity of lateral stability is normal,and the statistical law of comfort is not very sure,but it also has certain regularity.3)Based on the results of dynamic simulation,the rain flow statistics of forces of vertical spring,anti-snake damper and anti-roll torsion bar are obtained,and the time domain and frequency domain analysis are carried out.It is found that the higher the speed is,the load of the two important suspension elements is increasing,and the maximum cumulative number of the anti-roll torsion bar increases with the decrease of the friction coefficient,and it increases with the gauge increase.4)The relationship between the load of the anti-snakes damper and the comfort index is not obvious,but the relationship between the load of the anti-rolling torsion bar and the comfort index is obvious,and both of them increase together.This is related to the snake movement.The low frequency hunting motion causes the car body roll to be obvious,and the sensitive frequency of comfort index is also in this range.