Study On The Effect Of Wheel Polygons On The Dynamic Performance Of High-speed Trains

With the increasing service time and mileage of high-speed trains,polygonal wear of wheel treads is becoming more and more common,and is frequently seen in vehicles operating on many high-speed railway lines such as Wuhan-Guangzhou and Harbin-Dalian in China.The appearance of wheel polygons deteriorates the wheel-rail relationship,causing wheel-rail impact and posing a potential threat to the safety of train operation.Therefore,it is necessary to conduct research on wheel polygons to ensure the safety,stability and smoothness of high-speed train operation.In this paper,the sub-structure reduction and modal analysis are carried out by the finite element analysis software ANSYS to establish the flexible wheel pair sub-structure,and the rigid-flexible coupling dynamics model of high-speed trains is established in conjunction with the multi-body dynamics analysis software SIMPACK.The following analysis and research works were carried out specifically.(1)Analyze the vehicle dynamics performance of flexible wheelset.According to the actual situation of multi speed collinear operation,the curve track of 200～350km/h collinear operation is designed for comparison,and the results show that the results of safety indexes such as wheel-track vertical force and wheel load reduction rate of the traditional rigid body model are on the conservative side;for the stability problem of vehicle operation,the stability of the rigid-flexible coupling model is found to be decreased by the speed reduction method of comparison;for the vibration and transmission of the vehicle system using flexible wheelset,the vibration of the wheel pair,axlebox,frame and vehicle body are compared in the time and frequency domains.(2)Study the dynamics of wheel polygons based on the rigid-flexible coupling model.In order to understand the effect of wheel polygons on the stability of the vehicle system,the comparison of nonlinear critical speed was carried out;to clarify the effect of higher-order wheel polygons on the safety index,a comparative analysis of the 10～22 order polygons in the range of 0.01～0.05 mm wear amplitude was carried out under a high-speed linear track of250～350km/h with wheel polygons as the only variable,and the results showed that the wheel-rail The vertical force changes drastically;further in the curve track coupled with German spectrum track unevenness study,it is found that the wheel load reduction rate change sensitive and easily reach the limit value.In addition,it was found that the smoothness of vehicle operation is less affected by polygons.(3)Analysis of the vibration response of the axlebox and the effect of changes in vehicle system parameters when the wheels are polygonal.In order to study the vibration situation when the wheel polygons,the axlebox was used as the monitoring point for simulation,and it was found that the vertical vibration of the axlebox was intense,and the characteristic frequencies of the wheel polygons were retained in the frequency domain,which could be used to monitor and identify the wheel polygons based on this;in order to explore the optimization of the vehicle system parameters when the wheel polygons were used,the effects of different one-series suspension parameters,wheel-rail matching relationship and wheel radius were compared,and the results showed that the LMA tread and CHN60 rail surface are best matched,and increasing the damping of the one-series vertical damper can improve the wheel-rail vertical force,derailment coefficient and wheel load reduction rate to a certain extent,while reducing the axlebox vibration.