Study On Optimization Of Wheel Re-profiling Strategy Based On Vehicle Dynamic Performance

With the rapid development of metro lines,the proportion of subway in urban traffic is becoming more and more important.In the total maintenance cost of metro vehicles,the maintenance cost of wheelset is more than 30% generally.The maintenance cost of wheelset is mainly produced in the repair and replacement of wheelset.Because of the high cost of wheelset maintenance and unreasonable repair,there is high engineering practical value to study how to reduce and optimize the cost of wheelset maintenance and improve the service life of wheelset.For the wheelsets operating on a China metro line,this paper carries out studies on both the lateral wear and circumferential wear of the wheelsets.Under the condition of good dynamic performance safety,the vehicle U-turning operation,regular checking and re-profiling,and automatic matching multi-template for economical re-profiling are put forward.For the different polygon orders,their safety limits are set up.The results and conclusions are as follows:(1)Field investigation shows that there are serious wheel tread wear and flange wear.Train running can't be turned around,and unsymmetrical distribution of the left and right curves is the main cause of the unsymmetrical tread wear of wheelsets.There is a polygonal wear of 5~8 order on the wheels.The vibration frequency of the axle boxes of the vehicles is consistent with the passing frequency of the wheel roundness.P2 of track is the cause of the initiation and development of the 5~8 order polygon.(2)A metro vehicle/track coupling dynamic model is set up using the commercial code SIMPACK and verified through filed tests.The dynamical simulation results by using the model show that in the distance travelled of 200 thousand kilometers,the indexes of the stability,riding comfort and curving ability of the vehicles are stable and are within their limits of safety.(3)According to the influence of wheelset rolling diameter difference on the vehicle dynamic performance,the periods of train U-turning operation and wheel re-profiling are analyzed,the U-turning period is 5.3 thousand kilometers and the re-profiling period is 105 thousand kilometers.(4)Re-profiling is the main cause of wheel tread diameter loss.In order to improve the economy of wheel re-profiling,we use 4 kinds of common thin flange wheel profiles as templates,and design an automatic matching template program.Under the premise of ensuring the rolling diameter difference criterion,the automatic matching template should minimize the tread cutting while ensuring the thickness of the flange as large as possible.(5)A rigid-flexible coupling dynamic model is developed and verified.Within the 10 order wheel polygon,the dynamic characteristics of the vehicle are calculated with considering the change of the polygonal order and the amplitude of the out-of-roundness.The safety limits of out-of-roundness,and the limits of wheel re-profiling are proposed.(6)The influence of train U-turning operation on wheel use life,automatic matching template re-profiling program and the limits of re-profiling are analyzed.The results show that the improved strategies of wheelset maintenance and train operation can reduce the loss of wheel tread material effectively,prolong the service life of wheelsets and reduce maintenance costs.