Wheelset Longitudinal Vibration Analysis And The Correlation Dynamic Performance Investigation

The wheel tread spalling phenomena of railway vehicle is a difficult problem in the world. The phenomena and mechanism of the wheel/rail longitudinal dynamic acceleration increase abnormal is researched in this paper. Put forward the new opinion of the solution method of wheel tread spalling problem through the point of view of improve the wheel set longitudinal dynamic performance of the railway vehicles. The main research contents and results are shown as follows.1. The longitudinal vibration models which consists of 7 degrees of freedom of traditional wheel set, independently rotating wheel, elasto-damper coupled wheel set were set up respectively to research the common character of the elasticity orientated wheel set longitudinal vibration.In which the trace method were adopted in calculation of the wheel/rail space geometry contact relation, and the wheel jump phenomena and the elasticity compress distortion were considered also. The Kalker simple method were adopted in the creep force calculation, and the constraint equation method, nonlinear Hertz elasticity theory and the single side spring damp force element method were adopted respectively to calculate the wheel/rail normal force, compared the influence of different methods to the wheel set longitudinal vibration character. The influence of torsion stiffness of the wheel axle and the track irregularity to wheel set longitudinal vibration were considered also.Results: the wheel set longitudinal friction excited vibration is general phenomena which may induce to violent resonance vibrations at some conditions. The happen condition of wheel set longitudinal vibration resonance is acquired in the research, and put forward the simple forecast formula of the wheel set forward danger speed at which may induce the wheel set longitudinal vibration resonance.2. analyses the influences of track irregularity, adhesion coefficient, wheel set mass and longitudinal stiffness in primary suspension to wheel set longitudinal vibration resonance based on the simplify model in detail. As the universality of the wheel set longitudinal vibration, the results of simplify model has reference and guide meaning to railway vehicles abnormal chatter phenomena and the wheel fatigue damage phenomena.Results: wheel set longitudinal violent vibration resonance has big relation with the track irregularity, adhesion coefficient, wheel set mass and longitudinal stiffness in primary suspension.3. the whole locomotive dynamic simulation model of DF_8B were setup based on the soft ware SIMPACK, the longitudinal vibration character of elasticity oriented wheel set were carried from the point of view of whole locomotive and analyses the influence of parameter of the locomotive to the wheel set longitudinal vibration.Results: except above influence factors, change the wheel load and the longitudinal stiffness of primary suspension or increase the longitudinal damp of primary suspension can depress the wheel set longitudinal violent vibration. Improve the wheel tread spalling phenomena caused by violent longitudinal vibration.4. the line tests were carried with the DF_8B locomotive which has a big problem of serious polygon of wheel in kuerle of Xinjiang province; The DF₂₁ locomotive on the Kunming meter track has done 2 years line tests after done the improve method to solve the serious wheel tread spalling phenomena.Results: the line tests shown that the wheel set longitudinal vibration acceleration of the locomotive is really quite exceed the normal scope in some conditions, the investigate data shown that as the damp function of the outer part of the wheel and the inner part of the wheel, the wheel tread spalling phenomena of the locomotive with the integer wheel is much serious than the locomotive which adopted the separate wheel; the improve method which was based the new viewpoint has solved the wheel tread spalling phenomena of the locomotive on Kunming meter track.