STP1548

    Material Response Bearing Testing under Vibration Loading

    Published: Oct 2012


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    Abstract

    In a number of bearing application areas, failure analyses point to machine vibrations as a cause of service life reduction. To simulate experimentally the initiating damage characteristics as a consequence of vibrationally loaded rolling contact, a specific test rig is designed. A cylindrical roller bearing can be subjected to axial, radial, and tangential vibrations during the run. Vibration frequency and loading, rotational speed, and radial load are adjustable over a certain range. The bearing can be oil or grease lubricated. Vibrations cause an increase of the bearing running temperature, which is measured by thermo-couples and recorded online. The temperature rise, mainly depending on the effective oscillation velocity and the Hertzian pressure, indicates mixed friction as a result of vibration loading. Mixed friction produces polishing wear at the raceway. Further material responses to vibration loading are the formation of near-surface compressive residual stresses and alteration of the dislocation structure, surface induced cracks, and material delamination. As investigation methods, X-ray diffraction residual stress measurement and scanning electron microscopy are applied. Lubricant aging is verified by infrared spectroscopy. The dissolution of MnS inclusions on the raceway, proved by electron probe micro-analysis, indicates the impact of mixed friction on tribochemical processes. The changes of the X-ray diffraction measures reveal material aging. The relevant range of vibrationally increased friction coefficients necessary to build up compressive residual stresses is estimated by a model approach.

    Keywords:

    machine vibrations, bearing vibration test rig, mixed friction, residual stress, X-ray diffraction line broadening, friction coefficient, tribological rolling contact model


    Author Information:

    Nierlich, Wolfgang
    SKF GmbH, Dept. of Material Physics, Schweinfurt,

    Gegner, Jürgen
    SKF GmbH, Dept. of Material Physics, Schweinfurt,

    Univ. of Siegen, Institute of Material Science, Siegen,


    Paper ID: STP104653

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP104653


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