In this work, a simulation tool intended to study the evolution of the rail roughness has been presented. The simulation tool consists of a cyclic vehicle-track system model, a rotating flexible wheelset model, a wheel-rail contact model and a wear theory. The model of the vehicle-track system assumes the hypotheses of periodicity and, consequently, it is considered as cyclic. The adoption of hypotheses of periodicity permits to eliminate the border effects and to perform integrations without time limitation since the vehicle does not reach the border of the track, as happens in finite track models. Regarding the wheelset model, its flexibility and the effects associated with the rotation are taken into account, namely the gyroscopic effect and the effect of mobile force of the contact point with respect to the wheelset. The formulation of the flexible wheelset model uses a set of Eulerian modal coordinates, and it is based on the position of a spatial point in opposition to the Lagrangian formulation commonly used in mechanical engineering. The Eulerian formulation presents a series of advantages. Firstly, the wheel-rail contact force is applied on the wheelset at spatial points, whose positions remain unchanged. Consequently, the term of the generalised force becomes significantly simplified. Secondly, from another viewpoint, the wheel-rail contact theories were developed through Eulerian coordinates and, therefore, the formulation of the creep velocities is notably simplified, since the use of Lagrangian coordinate forces to implement convective terms complicates significantly the calculation. Finally, the Eulerian formulation enables the generation of coherent solid-air meshes in acoustic problems since the rotation of the mesh is not required. In this research, further insight into the mechanisms related to the dynamics of the wheeltrack system that promote the growth of rail corrugation has been gained. By using the Campbell diagram, the wheelset vibration modes responsible for a complex dynamics have been identified. This complex behaviour leads to high forces at the wheel-rail contact and wear. Specifically, the coupled influence of the third bending mode of the wheelset and the wheel modes on the growth of rail corrugation are analysed. The possible wavelength-fixing mechanism that has been identified is not constant in frequency, but it depends on the velocity of the vehicle.


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    Titel :

    Simulation of the evolution of rail corrugation using a rotating flexible wheelset model


    Beteiligte:
    Vila, Paloma (Autor:in) / Fayos, Juan (Autor:in) / Baeza, Luis (Autor:in)


    Erscheinungsdatum :

    2011


    Format / Umfang :

    21 Seiten, 13 Bilder, 3 Tabellen, 17 Quellen




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch