Study On Effect Of Wheel-rail Coupled Dynamic Response By Rail Corrugation Of Heavy Haul Railway

Heavy haul transport,which can effectively enlarge the railway capacity and transporting efficiency,has become the main development direction of China’s railway freight.However,the increase of the axle weight and running speed brings detrimental effect to the wheel-rail interaction,especially leads to constant increase of the vertical wheel-rail interaction force.The rail corrugation causes the intense vibration of the vehicle track structure,which also influences the security of the vehicle,shortens the service life of the vehicle and track structural parts,and even causes the derailment accident.The vertical coupled dynamic model for a freight train and ballast track is established on the basis of the vehicle-track coupled dynamics.It can solve the vehicle-track dynamics nonlinear equations accurately by converting the numerical vibration equations of vehicle subsystem and track subsystem into matrix forms.Continuous harmonic wave is used to simulate rail corrugation as excitation on wheel-rail,and the simulation calculation program is made to study the effect on integrated system dynamic response.With regards to the calculation of the numerical data,the freight trains,whose axle weight are 25 t,27t and 30 t running at the speed of 60km/h,80km/h and 100km/h,are selected respectively.The effects of rail corrugation are considered,which have different wavelengths and wave depths on wheel-rail dynamic property and the safety performance of freight train running.Finally,the safety threshold of rail corrugation will be determined on the basis of the property of running security.The results show as follows.1.For the selected rail corrugation given the same wavelength,the vertical force of wheel-rail,reduction rate of wheel load,vibration acceleration of wheel and rail increases along with the increasing of the wave depth;The corresponding value of the wheel-rail dynamic response will reduce if the condition is opposite.2.Particularly,when the freight train is running at the speed of 60km/h and the corrugation excitation length is 250 mm,the corrugation vibration frequency is close to the wheel-rail vibration frequency which causes resonance phenomenon and increases the wheel-rail interaction.3.For different axle weights and different speed,the dynamic response indexes of the wheel-rail increase with the increasing of the wavelength at first,but decrease after the peak in the process of gradually increasing the corrugation length from 10 mm to 250 mm.When the corrugation length exceeds the critical length,the corresponding indexes increase along with the increasing of the wave depth and the linear change patters are shown in particular sections.4.Based on relevant relationship between the critical wavelength with axle weight and speed,when the safety threshold value of the wavelength and depth of the rail corrugation is calculated under the same condition,the vehicle will be operated safely if the wavelength exceeds the critical wavelength or the wave depth is less than the critical wave depth.