Stability of high-speed train

In order to study the straight and circular curved track stability of each vehicle in the train set, a mathematical model of vehicle system with 17 freedom degrees was set up. The lateral component of coupler force was considered. The coupler force of vehicle(motor car or trailer car), which is the function of train speed and vehicle position in the train set, was determined by the resistant force of train operation. Three types of train compositions, 2M9T, 3M8T and 6M5T were taken into account. The Newton-Raphson iteration method was utilized to determine the equilibrium position of vehicle system, the QR method was adopted to calculate the eigenvalues of the system Jacobian matrix and the critical speed of the system where the equilibrium position became unstable was searched by the two divided method. The calculation results show that coupler force has little effect on the critical speed of each vehicle in the train set on straight track, but has certain effect for vehicle on curved track, the critical speed on curved track is lower than on straight track, the smaller the curve radius is, the lower the critical speed is, so the influence of coupler force on the critical speed of vehicle must be considered, when train runs on curved track.