Study On Whell/Rail Normal Cotnact Considering Wheel Wear And Out Of Roundness

With the rapid development of the China high-speed railways, several high-speed lines have been operated commercially. Since the speed of the train is up to300km/h, the vehicle dynamic performance is affected significantly by wheel OOR (out of roundness). In this paper, the accurate three dimensional wheel/rail model considering the wheel OOR is set up. When the vehicle runs some kilometers, the wheel wear happens and the curvature of the wheel tread cannot accurately obtained due to the wheel profile wear. Thus, the Non-Hertz contact theory is used, and the wheel-rail contact model based on the theory is derived, which can avoid solving the curvature problem by the classic Hertz contact theory. Then, the program which can solve the normal contact problem for arbitrary wheel/rail profiles is developed by using Matlab。The tangential contact problem turns to be non-steady state if the wheel OOR is considered, it is assumed that the normal contact is not affected by the tangential contact. Thus, only the normal contact problem for the wheel/rail in the right side is studied. Firstly, the effect of the wheel/rail geometric parameters on normal contact is analyzed for normal wheel without OOR. Secondly, according to the measured data of wheel wear tracking test, the development trend of wheel wear is summarized through data processing and analyzing, and the relationship between wear and normal contact is analyzed. Finally, the second-order, third-order and20th-order OOR are chosen as examples, the normal contact characteristic in the rolling process for OOR wheel is studied in detail. The influence of the order and amplitude of OOR on normal contact is investigated.Among the wheel/rail geometrical parameters, the rail cant and profiles of wheel and rail have obvious influence on normal contact, while the lateral displacement and yaw angle have certain influence. After wheel re-pro filing, the wheel wear rate increases which will reduce the wheel turning period. The normal contact stress tends to be stable after wheel wear and is not obvious related to the wear volume around the nominal rolling circle. The low order OOR will cause high amplitude stress with low frequency, and high order OOR will result in low amplitude stress with high frequency. The wheel OOR will directly lead to obvious change of the wheel/rail contact patches.