Wheelset Dynamics with Rail/Wheel Contact Constrain
Shu Xinggao  Hong Jiazhen  He Qiyong
(Shanghai Jiaotong University, 200030)（China Academy of Railway Sciences, 100081）

Abstract: In this paper, the rail/wheel contact is modeled as a rigid constrain, the nonholonomic kinematics constrain equation is derived in detail. By taking into account the inertial force and gyroscopic moment caused by moving track reference, the dynamics equation of wheelset on arbitrary curving track is established with absolute coordinate method. The normal force and creep force are got simultaneously through iteration of Lagrange multiplier. According to the equivalent force and moment, two contact points are reduced to one equivalent contact point. This dynamics model is verified by simulating the Parscal's benchmark and the hunting movement of free wheelset, it can be used as rail/ wheel element in a general vehicle system dynamics simulation software.
Keywords: rail/ wheel constrain, wheelset dynamics, hunting movement, nonholonomic constrain.