Stability of vibrations of a moving railway vehicle along an infinite complex three-part viscoelastic beam/foundation system

Abstract

Vibrations of a railway vehicle that moves on a long three-part viscoelastic system can become unstable because of elastic waves that the railway vehicle generates in the structure. A typical example of the railway vehicle that can experience such instability is a high-speed train. Moving with a sufficiently high speed, this train could generate in the railway track elastic waves, whose reaction might destabilize vibrations of the train. In this paper, an improved procedure and parametric analysis of stability of vibrations of a railway vehicle system were carried out with the emphasis on the effects of damping of the secondary suspension of the railway vehicle, stiffness of the secondary suspension of railway vehicle, mass of the railway vehicle, wheelbase and positions of the supports. The d-decomposition method and the principle of the argument are adopted to handle cumbersome expressions that occur due to the present railway vehicle system model. The railway vehicle system is modeled by elastically connected rigid bars on identical supports. Identical supports are modeled as a system of springs and dashpots attached to the bars on one side, which interact with the beam through the concentrated masses on the other side. The paper analyzes the case when the railway vehicle system exceeds the minimum phase velocity of waves in the beam, which may lead to the vibration of the system becoming unstable. The instability intervals are determined for varying parameters and important conclusions are performed.