The railway track and its substructure is idealized by an infinitely long beam subjected to a movingg lumped mass. The speed of the movement is held constant. The beam rests on Winkler foundation the stiffness of which is a random function of the length coordinate. The surface of rails possesses random track irregularities. The applied method of intergal spectral decomposition enables a qualitative analysis which coincides with analytical results achieved using Marcov process theory together with the Fokker - Planck - Kolmogorov's equation. It is shown that it is necessary to assume at least a diffuse model of imperfections. Only in this case, it is possible to keep the law of energy equilibrium for infinitely long systems. The difference between the classic solution without imperfections and the mathematical mean value of the response is growing with increasing distance from the point of load application and in a certain distance the energy transits from the deterministic into the stochastic component of the response. There has been detected existence of a limit excitation frequency. The wave length produced by this excitation frequency is comparable with the mean correlation length of imperfections. An analogous effect can be seen in deterministic problems solved by the FEM due to continuum discretisation. The deflection of rails is charged by greater dispersion than their stresses. The track imperfections wear out the rail vehicles more than the rails. The overall dynamic and fatigue effects of vehicles on track with imperfections are greater than for ideal case without inspections. The present paper presents a theoretical analysis and it needs a numerical evaluation of several special cases and experimental verificationn in future.


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    Title :

    Stochastic modelling of track and its substructure


    Additional title:

    Die stochastische Modellierung des Schienenstrangs und seines Unterbaus


    Contributors:
    Naprstek, J. (author) / Fryba, L. (author)


    Publication date :

    1995


    Size :

    14 Seiten, 3 Bilder, 10 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Stochastic Modelling of Track and its Substructure

    NÁPRSTEK, JŘÍ / FRÝBA, LADISLAV | Taylor & Francis Verlag | 1995


    Stochastic Modelling of Track and its Substructure

    Náprstek, J. | Online Contents | 1995


    Stochastic Modelling of Track and its Substructure

    Naprstek, J. / Fryba, L. | British Library Conference Proceedings | 1995