Study On The Influence Of Wheel-rail Periodic Wear On Dynamic Characteristics Of High-speed Wheel-rail System

As an important carrier of transportation,rail vehicles,as their operating speeds continue to increase,the wheel and rail periodic wear caused by wheel-rail interaction-wheel polygon wear and rail wave grinding phenomenon is also becoming more and more serious.Wheel polygon wear and rail wave grinding not only increase the impact vibration between the wheel and rail,but also exacerbate the interaction between the wheel and rail,and seriously threaten the safety of train operation.In order to ensure the safety while taking into account the economics,it provides technical support for the development of reasonable wheel repair and rail grinding cycle.In this paper,the cause of polygon formation is preliminarily discussed from the angle of combining experiment with simulation.At the same time,according to the minimum diameter range of the trailer wheel of a certain type of high-speed EMU,the dynamic model of vehicle orbit rigid coupling is established under different wheel diameters.The influence of wheel and rail periodic wear on the vibration characteristics of the wheel-rail system is studied.The safety limits of the wheel-rail under different wheel diameters are studied.The specific research work is as follows:1.According to the dynamic parameters of a high-speed EMU,the rigid-flexible coupling dynamics model of the vehicle based on flexible track system,flexible wheelset and flexible axle box is established.The comparison between the measured data and the measured data proves the flexible wheel-rail system.The rigid-flexible coupled dynamics model can be used to calculate high frequency vibrations.2.Through the long-term tracking test of the high-speed EMU,the distribution law of polygon wear under different wheel diameters and the development of polygons in adjacent repair cycles are obtained.The test results show that the wheel diameter is 860mm-880mm,mainly the 19th-order polygon,and the 890?920mm is mainly the 20th-order polygon.The vibration frequencies of the dominant order of the polygons are distributed around 565?590Hz.3.The possible sources and influencing factors of the dominant order formation of polygons are discussed.By measuring the vibration acceleration of axle box of different lines and vehicles in different service,it is found that the vibration frequency of 2.5m wheelbase vehicle running on ballastless track is around 567?596Hz.Combined with polygon test and coupled modal analysis of wheel-rail system,it is preliminarily inferred that the formation of higher-order polygon may originate from the third-order bending vibration of track and be related to the wheelbase.4.The rigid-flexible coupled dynamics model is used to analyze the influence of wheel-rail periodic wear on the vibration characteristics of the wheel-rail system.Considering the wave grinding of the rail,the influence of the polygon on the vibration characteristics of the high-speed train wheel and wheel is considered by the two different input modes of the wheel diameter difference function and the ideal harmonic function.The safety limits of polygon wear for different orders under different wheel diameters are given.5.The modal stress recovery method is used to analyze the polygon wear and operation speed of different orders and amplitudes,and the wheel polygon contact wear stress and the dynamic stress of the key axle of the axle under different running mileages in a repair cycle.Influence the law and use the complete finite element method for comparative analysis.