Study On Hunting Characteristics Of High-Speed Train

With the constant improvement of the train running speed, high speed trains in our country has exposed some dynamic problems, many of which are associated with hunting movement.The matching relationship of wheel and rail is one of the main reasons of hunting movement stability problem. Our country hasn’t a complete evaluation system of wheel/rail matching state, and the study on the relationship between wheel/rail matching state and hunting stability is also imperfect.For accurate assessment of wheel/rail matching state, and rapid prediction hunting stability of high-speed train, this paper has established dynamic simulation model of the free wheelset, the bogie and the vehicle system. Thesis around the high-speed trains in our country are discussed and analyzed, the main work are as follows:1. According to the calculation method of linearized wheel/rail contact geometry characteristic parameters (equivalent conicity, contact angle parameter and roll angle parameter), let the wheel/rail contact geometry relationship linearize between the three kinds of typical domestic wheel profile (S1002CN tread, XP55 tread and LMA tread) & their worn treads and the standard & the measured rails linear, calculate linear characteristic parameter, and find out the relationship between the roll angle parameter & the contact angle parameter and equivalent conicity which provides wheel/rail matching basis parameters for hunting stability analysis.2. The hunting frequency variation rule of the wheelset, the bogie and the vehicle and the main influencing factors, including the wheel-rail contact relationship (equivalent conicity, contact angle parameter and roll angle parameter), running speed, wheel-rail interface conditions (creep calculation method, Kalker coefficient weighting, friction coefficient) and the presence or absence of anti-yaw damper and track irregularity excitation are studied. On the basis of SIMPACK simulation results, get the hunting frequency formula by fitting the free wheelset, the bogie and the vehicle, in order to achieve the purpose of having more wide scope of application than the traditional theoretical formula.3.Critical speed of high-speed trains with equivalent linear conicity changing is calculated by using characteristic roots method, and the matching relations between equivalent conicity and the primary longitudinal positioning stiffness when carbody hunting occurs is found, and the difference between the linear and nonlinear critical speed is compared and anlalized.By using the numerical simulation method, the influence of roll angle parameter, contact angle parameter and the longitudinal and lateral positioning stiffness of the primary suspension on determining the linear and nonlinear critical speed damping ratio and its span of the vehicle are studied. In order to make the linear critical speed and the nonlinear critical speed close to equal, linearization method of nonlinear wheel/rail matching relationship is studied.