Research On Vehicle-Bridge Coupling Effect Of Different Wheel-Rail Contact Relations On Rigid Frame Bridge

With the rapid development of China high-speed railway,the proportion of bridges in the overall railway is increasing and the vehicle-bridge coupling problem is particularly important.The transmission of force between vehicles and bridges in railway bridges is through wheelrail contact relations.Different wheel-rail contact forces and thermal stresses caused by wheelrail flash temperature between wheels and rails caused by flash temperature can affect the coupling vibration of vehicles and bridges.A railway rigid frame bridge is taken as the engineering background in this paper.The two-dimensional thermal-mechanical coupled wheel-rail model with different friction coefficient and sliding speed is studied in ANSYS and the Mueller wheel-rail contact relationship considering the influence of temperature is modified.The difference between the wheel-rail contact relationship and the Mueller wheel-rail contact relationship and the non-elliptical wheel-rail contact relationship on the vehicle-bridge coupling vibration is compared through the joint simulation of ANSYS and UM and the rationality of the contact relation is verified.At the same time,the effects of different speed,vehicle weight,track irregularity wavelength and wheel-rail contact stiffness on vehicle-bridge coupling vibration are studied.The main conclusions are as follows:(1)Under different friction coefficient and sliding speed,the temperature between wheel and rail ranges from 540℃ to 900℃,the thermal stress generated by the flash temperature between wheel and rail can make the contact stress of wheel and rail increases about 20.4%;The equivalent stress and shear stress in the coupled field of thermal-structure are both larger than those in the field of structure.The equivalent stress and temperature between wheel and rail increase with the increase of friction coefficient and sliding speed.According to Carter twodimensional contact theory and the principle of force equivalence,it is deduced that temperature can increase the longitudinal creep rate by 0.45 times and the longitudinal creep rate in Mueller’s wheel/rail contact relationship is corrected.Under different axle load,friction factor and sliding velocity,the shear stresses of wheel and rail distribute in the form of "four-leaf clover" and the maximum shear stress is not on the contact surface of wheel and rail.(2)The effects of three different wheel-rail contact relationships on the vertical vibration of the bridge are basically the same,but the results of the lateral vibration of the bridge is greatly different;the three different wheel-rail contact relations have relatively little influence on the vertical acceleration and the horizontal and vertical stationarity of the train and have some influence on rate of wheel load reduction.But they have a great influence on the derailment coefficient,lateral acceleration and the lateral force of the wheel-rail.Comparing Mueller modified contact relation with Mueller contact relation,the difference of vehicle-bridge coupling lateral vibration is due to the thermal stress caused by the flash temperature in the wheel-rail contact patch,causing local deformation of the wheel-rail contact surface and causing erosion,which changes the contact state of the wheel-rail profile and leads to the change of wheel-rail contact force.(3)The dynamic response of the bridge increases with the increase of velocity.The derailment coefficient,wheel-rail lateral force and wheel load reduction rate of the train increase with the increase of speed,while the stability index,vertical force and acceleration do not change obviously with the increase of velocity.The evaluation indexes of vehicle-bridge coupling of bridges and trains increase with the increase of vehicle weight.The influence of track irregularity wavelength on the lateral vibration of bridges is relatively large and the sensitive irregularity wavelength of bridge lateral vibration is about 170 m.The influence of track irregularity wavelength on the dynamic index of trains are relatively large and nonlinear change.