INSTABILITY OF A BOGIE MOVING ON A FLEXIBLY SUPPORTED TIMOSHENKO BEAM

The stability of vibration of a bogie uniformly moving along a Timoshenko beam on a viscoelastic foundation has been studied. The bogie has been modelled by a rigid bar of a finite length on two identical supports. Each support consists of a spring and a dashpot connected in parallel. The upper ends of the supports are attached to the bar, whilst the lower ends are mounted onto concentrated masses through which the supports interact with the beam. It is assumed that the masses and the beam are always in contact. It is shown that when the velocity of the bogie exceeds the minimum phase velocity of waves in the beam, the vibration of the system may become unstable. The instability region is found in the space of the system parameters with the help of the D-decomposition method and the principle of the argument. An extended analysis of the effect of the bogie parameters on the model stability has been carried out.