Study On The Operation Safety And The Rail Wear About EMU Passing Through Small Radius Curves

The small radius curve track is one of the weak point of the railway.When the train is running on a small radius curve,because rail-wheel dynamic effects increase,the wheel rail wear is more serious which increases safety risks.Most of the domestic and international correlation researches focuses on the freight transportation line,there are few further study on the operation safety and the rail wear about EMU passing through small radius curves,and has no comprehensive system research approaches.To solve this problem,this study focuses on the effects of the operation safety and the rail wear due to EMUs on small radius curves.The primary research work are as follows:(1)3D dynamic models are established which including different types of EMU vehicles and 8 marshalling vehicles of EMU train-curve track coupling system based on multi-body dynamics modeling.In order to solve the calibration problem of the train-track coupling dynamic simulation model parameter,field tests are planned and conducted to calibrate and prove systemly the reliability and accuracy of the simulation model.(2)The research tests are carried out systemly about EMU passing through small radius curves.It is analyzed comprehensively about the dynamic characteristics of the vehicle and the track under the small radius curves,and found the dynamic characteristics and differences of the EMU' guide wheel,driven wheel and the wheels lie in outside and inside of curve,and the dynamic response of the track structure under the action of the wheels.It is got also that the acceleration and deceleration characteristics of the EMU's entering and exiting stations,as well as the variation of the dynamic performance of the vehicle and track in different sections.(3)It is studied Comprehensively on the influencing factors of safety risk of EMU passing throuth small radius curves,and it is acquired that the influence law of track irregularity,driving speed,curve radius,superelevation setting,gauge widening,rail-bottom slope,rail type,wheel-rail friction coefficient,straight Line length between two curves,type of turnout,direction of curve back of turnout,superelevation runoff,curve versine deviations,etc.The result shows that the safety control parameters of the EMU passing through the small radius curve are mainly derailment coefficient,and the main influencing factors are curve radius,unevenness,wheel-rail friction coefficient and wheel-rail profile matching.In order to increase safety of EMU passing through small radius curves,The tactics suggestions including allowable speed limit of curve,gauge widening,superelevation setting of “S” shape of curve,turnout selection,and rail-side friction coefficient control etc.are presented.(4)The inversion analysis of the EMU' derailment example on the small radius curve was carried out,and the derailment mechanism of the EMU was clearly proposed,that is,the combined effect of both deviation from the track unevenness and the deviation of the curve versine exceeding limit value,and the mismatch between the new wheel and the weared track,and and also the vehicle 5 of the EMU marshalling is in a disadvantage position.all those above are the fundamental reasons for the derailment of the EMU' 5th vehicle.(5)The distribution and development law of rail wear of small radius curves was obtained.Based on the analysis of variance of orthogonal test,the main factors affecting the wear of small-radius curved rails were found out,which are the wheel-rail friction coefficient,track irregularity,curve radius and vehicle operating speed;The influence of various factors on the wear of small radius curve rails was systematically studied.The formula for multivariable wear index based on the wheel-rail friction coefficient,track irregularity,running speed and curve radius was innovatively proposed.