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Rotating shaft and ball-surface life

  1. Jul 26, 2006 #1
    There is a rotating shaft which is in contact with a spherical ball. The ball is in contact with an outer casing.The casing is fixed to the ground.

    I want to estimate the life of the surface which is in contact. There are two surfaces i want to estimate the life for.

    1)surface of the rotor which is in contact with the ball

    2)surface of the casing which is in contact with the ball.

    Which surface will wear faster? Any proof of this.

    Which subject i should concentrate on ( i think mechanics or rotational mechanics-any web site for this) to understand this process.
  2. jcsd
  3. Jul 26, 2006 #2


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    Gold Member

    Chandran, you are way short of an answerable question. What are the various components made of? What are the machining tolerances? What sort of clearance? What sort of lubrication? What rpm with what sort of side/end loading? Are you starting to see the picture?
  4. Jul 27, 2006 #3


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    Science Advisor

    The biggest factors you are missing in your problem statement are the materials and the applied loads. The predominant stresses will be the Hertz contact stress. You will also have the other factors that Danger mentioned as well. It sounds conspicuously like you are trying to estimate the life of a bearing. If that is the case, you could find bearing life calculations in any design of machine elements book.
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