Research On The Evolution Law Of Wheel Polygon For Heavy-Haul Locomotive And Its Impact On Wheel-Rail Coupled Vibration

The wheel of heavy haul locomotive will cause uneven wear and spalling during long-term operation,and the wheel polygon is the main performance of uneven circumferential wear of the tread.When the polygonalization of wheel circumference is serious,it will cause impact vibration of locomotive and track system,which will pose a potential threat to the stability and safety of vehicle operation.Therefore,it is necessary to study the evolution law of wheel polygon of heavy haul locomotive and its influence on wheel-rail coupling vibration.In view of this,this paper takes 25 t four-axle high-power heavy-haul locomotive as the research object.The longitudinal-vertical coupling dynamic model of heavy-haul locomotive-track is established.Through field test,the wheel polygon data in the range of 0-170,000 km operation mileage are obtained,and its harmonic characteristics and evolution law are studied.The measured wheel polygon data are used as excitation of the dynamic model.The longitudinal/vertical dynamic interaction force between wheel and rail,acceleration of key components,contact spot between wheel and rail,normal and tangential contact stress are analyzed.Finally,the suggestions for controlling the local depression wave depth of wheel polygon are put forward.The field test results show that the main harmonic components of the wheel polygon of heavy haul locomotive mostly occur in the order of 1st to 10 th,and the wavelength is concentrated in the range of 556 to 3 890 mm.When the locomotive runs at 60-80 km/h,the vertical vibration in the frequency range of 4 to 43 Hz can be excited.With the increase of operating mileage,the radial deviation amplitude of wheel increase,and the wheel polygon harmonic of 1st-3th and 6-8th order increase most obviously.Dynamic simulation results show that the fluctuation range of dynamic force and acceleration of locomotive-track coupling system is not linearly increased during the evolution of wheel polygon,and the growth rate increases in the later period.Among the 1st-20 th order wheel polygon harmonics,the 7th order harmonics have the greatest influence on the vibration of locomotive-track coupling system.Longitudinal and vertical vibration attenuation effect is very significant in the process of upward transmission of locomotive system,in which the secondary suspension isolation effect is better than the primary,while the vertical vibration attenuation effect in the downward transmission of track system is not obvious.Longitudinal creep force,wheel-rail tangential stress and longitudinal acceleration fluctuation of locomotive components increase with the increase of traction force and wheel-rail friction coefficient.The friction coefficient of wheel and rail decreases,the traction performance of locomotive decreases,and the proportion of adhesion zone in contact patch area decreases.On the basis of synthetically considering four kinds of control indexes,the final limit value of local depression wave depth of wheel polygon is given.