High Temperature Arching Waveforms Of CRTS ? Slab Track And Dynamic Characteristics Analysis

With the frequent occurrence of extreme high temperature climate in summer,under the effect of a large longitudinal the pressure of the temperature,the CRTS II track slab(II slab track)is deformed on the upper arch,which seriously affects the high-speed operation of the train.Therefore,it is necessary to study the effects of the arch waveform on the II track slab and its dynamic characteristics.Firstly,according to the structure composition of II slab track and its stress characteristics under extreme high temperature loads,the problem of instability of II slab track under the effect of an overall warming temperature load is simplified to a vertical stability problem of the longitudinal load acting on a longitudinal uniform continuous structure with vertical support.Based on the euler beam deflection theory and energy method,the formula for the waveform of the arch on the II slab track is deduced.This formula is called euler's wave formula.Secondly,according to the similarity theory,the equation analysis method is used to determine the material and dimensions of the scale model test,design test fixtures,conduct tests,and analyze test data.The same non-linear finite element model was established and the numerical simulation results were extracted.The results were compared with the euler waveform results and the experimental results.The study found that with the increase of axial load,the steady state stage,the expansion stage and the unsteady stage appear successively in the process of arching on the track slab.Before the destabilization stage,the data obtained by the three methods agree well with the relationship between the peak value of the upper arch and the axial pressure.The similarity between the analytical method and the finite element method waveform is as high as 95% or more.The euler waveform is representative in the steady stage and the expansion stage.Finally,based on the euler waveforms,based on the wheel-rail system dynamics and multi-rigid body dynamics,a vertical coupled dynamic model of the vehicle-upright track with upper arch defects is established.The influence of euler waveform and traditional sinusoidal waveform on train dynamic characteristics is compared.The influence of different peaks of the upper arch on the dynamic characteristics of the vehicle when the arch shape on the track slab is euler waveform is studied.The results show that the acceleration of the car body,the vertical force of the wheel-rail,and the vertical displacement of the track structure generated by the euler waveform are slightly smaller than those of the sinusoidal waveform,but the overall difference is not significant;When the train passes through the upper arch section,the vertical acceleration of the track slab increases greatly,and the maximum value appears at the location of the upper arch peak;the maximum value of the vertical displacement of the track structure occurs at the peak position when the train passes through the upper arch section.When the peak value of the arch on the track slab is 1.5mm,it should be maintained in time.