Dynamic Properties of Two-Axle Freight Wagon with UIC Double-Link Suspension as a Non-smooth System with Dry Friction

Abstract

The influence of chosen parameters on the lateral dynamic behavior of the two-axle freight wagon with UIC double-link suspension is presented. This type of suspension uses the advantages of the studied non-smooth mechanical system, since dry friction is used to damp the system vibrations. Mathematical models of this suspension with and without lateral bump-stop are derived owing to non-smooth mechanics assumptions being based on the Coulomb law regarding friction and implemented into the MBS program. Numerical simulations of dynamics of the analyzed system are performed on a straight track followed by the methods appropriate for predicting the dynamic stability of railway vehicles. A dynamic reply of the vehicle to the railway track excitation, in the form of the initial condition, is monitored and studied. The carried out analysis mainly concerns the investigation of limit cycle dynamics exhibited by the system elements in terms of safety of the freight wagon. In addition, an influence of the friction coefficient coupling the interacting elements of suspension and being responsible for damping properties of our non-smooth system is analyzed. Furthermore, an occurrence of a low critical speed is illustrated and its physical meaning is explained, and the usefulness of applying the lateral bump-stop in the structure of UIC double-link suspension is justified.