Damage Prediction And Dynamic Analysis Of Electric Locomotive Wheel Tread With Different Profiles

The wheel-rail contact conditions of some heavy haul locomotives in China are deteriorating year by year,which leads to the aggravation of wheel tread wear and rolling contact fatigue damage,thus reducing the locomotive operation performance.In order to prevent more serious damage to locomotive running parts or rails,when the wheel is damaged,the locomotive department needs to restore the wheel profile to the health standard in time through operations such as re-profiling,but it will also face additional losses caused by excessive re-profiling.These problems bring labor costs and economic losses to the railroad sector.Therefore,this paper takes the electric locomotive in service as the research object,and takes the locomotive JM₃standard profile and its thin-rim profile wheel as the basic analysis dimension to realize the prediction of the wheel tread damage type and damage degree under different working conditions,and The influence of profile changes after wheel wear on the dynamic performance of the locomotive is compared.The specific research content of this paper is as follows:（1）The line and service locomotive of a locomotive depot were investigated.The line information,locomotive parameters,repair data and wheel damage morphology were statistically analyzed.The measurement of the profile of the vehicle was completed.It was found that the wheel tread damage of the locomotive in service on the line had complex causes and various types of damage,and there were different characteristics in the lateral position,shaft position and wheel position of the tread.According to the investigation,the research theories and methods of wheel tread damage are compared,and the damage prediction method based on damage function model and the wear calculation method based on Archard theory are determined.（2）The dynamic model of locomotive and the rolling contact fatigue prediction model of wheel are established.The damage characteristics of wheel tread under various combined conditions such as different running speeds,radius curves and rail bottom slope parameters are predicted.The results show that the damage of wheel tread at different axle positions is affected by the curve passing speed to different degrees,and the dominant types of wheel damage at different axle positions are also different.The damage amplitude of each axle wheel tread is negatively correlated with the radius of the curve,and the damage type gradually changes from wear-dominated to RCF-dominated as the curve radius increases.On the curve line,the lateral distribution range of the guide wheel tread damage is more susceptible to the rail cant parameters.（3）The tread damage law of different profile wheels under different working conditions is different.The left wheel of the guide shaft has the largest tread damage amplitude under the JM₃-32 profile condition,and the minimum damage amplitude under the JM₃ profile condition.The RCF damage amplitude of the left wheel of the non-steering end axle is negatively correlated with the speed under the condition of thin rim profile.The tread damage amplitude of the right wheel under the condition of JM₃ profile is far greater than that of other profiles.With the increase of curve radius,the tread damage degree of JM₃ standard profile and thin flange profile wheel gradually approaches,and it is found that the total tread damage is not linearly related to the flange thickness.Under the condition of 1/40 rail cant,the thinner the rim is,the closer the tread damage area is to the rim side.（4）Based on the Archard wear theory,the iterative calculation of wheel wear profile is realized.The dynamic performance analysis of locomotives under the condition of 50,000 km,100,000 km and 150,000 km wear wheels is carried out respectively.The results show that the profile of the guide axle car is the most obvious,followed by the intermediate axle and the non-guide end axle wheel.Wheel wear has a great influence on the stability of locomotive serpentine operation,but there is no nonlinear relationship between running mileage and instability critical speed.With the increase of wear mileage,the oscillation amplitude of wheel-rail lateral force and vertical force increases gradually,and the maximum absolute value is positively correlated with wear mileage.In addition,wheel wear has the greatest influence on wheel-rail lateral force under 400m radius curve condition,and has little influence on wheel-rail vertical force and wheel-axle lateral force.