LATERAL STABILITY, BIFURCATION AND CHAOS OF HIGH-SPEED RAILWAY PASSENGER CAR SYSTEM

摘要

Based on the motion stability and bifurcation theory of dynamical system, a more representative high-speed four-axis railway passenger car which has seventeen degrees of freedom, considering the lateral motion, roll angle and yaw angle of the car body and the truck frame, and the lateral motion and yaw angle of the four wheelsets, has been thoroughly investigated due to its complicated dynamics. The creep forces between the wheel and the rail in rolling contact are decided by the Vermeulen-Johnson creep force laws and the flange forces are simulated by a piecewise function. The lateral stability and bifurcation of the vehicle system running on an ideal straight and perfect track have been studied by bifurcate software AUTO which was originally designed to analyze stability and bifurcation problems of differential equations. Meanwhile, chaotic motions and the route to chaos of vehicle system at high speed have been analyzed as well. Research results show that a variety of characteristics such as linear critical speed and nonlinear critical speed, and dynamic process can be obtained by applying AUTO. In addition, the influence of adhesion coefficient on nonlinear critical speed is discussed. This research provides academic basis for bettering dynamic performance of lateral stability and routine operations of high-speed railway passenger car to some extent.