A transient dynamic study of the self-excited vibration of a railway wheel set–track system induced by saturated creep forces

Abstract

Two dynamic models of a wheel set-track system on a tight curved track and on a straight track are established, in which the friction coupling between the wheel and rail is taken into account. Both the transient dynamic and complex eigenvalue analyses are performed to study the unstable transient dynamics and stability of the wheel set-track system. It is assumed that in the models creep forces between wheels and rails are saturated, that is, approximately equal to the normal forces multiplied by the dynamic coefficients of friction. The simulation results demonstrate that the saturated creep force can induce self-excited vibration of the wheel set-track system. The normal contact force between the wheel and rail fluctuates at the same frequency as the wheel and rail vibrate when the self-excited vibration occurs. And the fluctuation frequency of the normal contact force falls into the range of 60-500 Hz, which corresponds to the frequency range of rail corrugation. This phenomenon indicates that the self-excited vibration of the wheel set-track system may be a main cause of rail corrugation occurrence. Parameter sensitivity analysis shows that the stiffness and damping of the rail fastener have important influences on the oscillation amplitude of the normal contact force. Bringing the friction coefficient below a certain level and increasing the damping of the rail fastener can suppress rail corrugation.

Effect of the unstable vibration of the disc brake system of high-speed trains on wheel polygonalization

“…The two approaches are known to produce different results that should not be far away from each other, which is confirmed by the above results of frequencies. 24 The above analysis proves that the friction-induced vibration of the disc brake system can cause the normal contact forces on the contact surfaces of wheels and rails to fluctuate at the same frequency. According to equation (11), the friction work on the contact surfaces of wheels and rails will also fluctuate at the same frequency as the normal force fluctuates.…”

“…22,23 and Qian et al. 24 The rail is fastened to the track slab by fastening and rail pads, the rail pads and fastening are simplified as a series of massless dampers and springs in the model, as shown in Figure 2(b). The springs and dampers are uniformly distributed on each node.…”

“…The total normal force becomes the dominant factor affecting the friction work rate. When the friction-induced vibration imposed by the wheel–rail friction force and the disc–pad friction force between the brake pads and brake discs occurs, the wheel–rail normal contact force will fluctuate in the same way, 24 which will cause the friction power H to fluctuate at the same frequency. Finally, the wear volume w will also fluctuate in the same way as the friction power, according to equation (11).…”

Numerical investigation of the effects of rail vibration absorbers on wear behaviour of rail surface

“…The detailed derivation process of equations (3) and (4) was presented in Oden and Pires 19 and Qian et al. 20…”

Investigation into rail corrugation in high-speed railway tracks from the viewpoint of the frictional self-excited vibration of a wheel–rail system

“…Different from the second torsional resonance of driven axles, the saturated creep forceinduced mode coupling between wheel and rail leads to selfexcited vibration of the wheel-rail system to create corrugation. From the new insight of friction-induced vibration causing rail corrugation, one can objectively explain many rail corrugation phenomena such as most rail corrugations occurring on the low rail of tight curved tracks and little rail corrugation occurring in the curved track whose radius is larger than 600-700 m [25,26].…”