Identification Of Out-of-round Wheel Based On The Wheel-rail Vertical Force Continuous Measurement

With the rapid development of railway industry,the axle load and running speed of the train have gradually improved,and the relationship between wheel and rail has become more complicated.When the train is in operation and reaches a certain mileage,the train wheels will have cyclic wear in the circumferential direction,which is called out-of-round wheel.Out-of-round wheel has occurred in the metro,the rail and the high-speed rail vehicles,and the domestic scholars have discovered the 20-order wheel polygon by the actual measurement.Out-of-round wheel serious impact of track structure and body itself,between the wheel/rail dynamic force,the serious influence vehicle and track the service life of components,reduce the passengers ride comfort,threat to security,out-of-round wheel problem has been the focal point of the track relationship and the difficult question.Due to the complexity of out-of-round wheel formation mechanism,and it will change with the increase of operating mileage,there is no accurate method for how to recognize the out-of-round wheel.Therefore,it is of great significance to make a comprehensive and in-depth study on the problem of train out-of-round wheel identification.In this paper,the continuous measurement method of wheel-rail vertical force is used to study the problem of out-of-round wheel recognition.Firstly,the continuous test system of wheel and rail vertical force is applied to test the continuous strain signal of the rail,and then the continuous strain signal is collected and compared and analyzed.According to the geometrical characteristics of out-of-round wheels,a dynamic finite element model of "body-out-of-round wheel-rail" was established to study the influence of different wave depths,vehicle speeds,and polygon orders on the dynamic response of wheel-rail forces and track structures.Finally,the measured data is fitted,the sawtooth wave function is obtained,and the function is used as the calibration function of the out-of-round wheel identification,and the out-of-round wheel in the simulation model is identified.By comparison with the field measured results and simulation results prove the validity of the wheel/rail vertical force of continuous testing,analysis of the measured data,can be continuous calibration of wheel/rail force sawtooth wave function,and prove the function is not affected by the speed of the car.According to the analysis of the simulation model,the out-of-round wheel is divided into low order(1-5 order)and the high order(6-20 order).The analysis results show that the low-order out-of-round wheel has a small influence on the vertical force of wheel and rail,and the variation law is different from the higher order.Higher-order out-of-round wheel,with speed,no order number and the increase of the wave of deep,caused by wheel/rail vertical force also will increase.Sawtooth wave function of out-of-round wheel recognition as a result,the more obvious the conform to thecharacteristics of each order out-of-round wheel is verified based on the wheel/rail vertical force continuous testing method to identify the feasibility of the out-of-round wheel.