Stability of vehicles moving on an elastic foundation

Few studies have been made of the stability of a dynamic system moving on an infinite continuum. Here a general method of analysis of such coupled systems is presented. It shows that vehicles possessing a single point of contact with the foundation become unstable above a velocity always higher than the critical speed defined in the classical constant moving force problem. Flutter speeds lower than this critical speed have been obtained in the case of vehicles with two points of contact. This destabilizing effect is due to the damping of the foundation. The evolution of the flutter boundaries as a function of the characteristics of the foundation is described for a typical vehicle.