how can we solve the problem of sliding of an aluminum specimen through drill chucks during tensile testing it?

We faced with a problem while designing a tensile test set-up, which is our graduation project in University. The problem is that we manufactured the test setup and we used two drill chucks (mandrels) for holding the test specimen, which is aluminum. However, when the system is started, the test specimen slides through the mandrels and we cannot finish the test.

How can we solve this problem? IT IS REALLY URGENT!!!

4 Answers

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  • Bomba
    Lv 7
    10 years ago
    Best Answer

    Edit

    Clamping the specimen is a common problem in tensile testing and so the usual sample is much wider at the two clamping surfaces than in the cross section being measured. That is the classic "dumbbell shape".

    Since you are using a drill chuck -type clamp, you may need to reduce or farther reduce the diameter of the round specimen in the middle by turning it down on a lathe.

    The flat surfaces three-jaw chuck will be making a line contact with the round specimen and so there is minimum area for holding friction. You can mill slight flats at 60 deg orientation on each end to enhance clamping.

    Regardless of the clamping technique, the middle will still need to be turned down so that it will be the weakest cross section of the test specimen.

  • 4 years ago

    Problem solving is two words, not a hyphenated word. Too many people try to hyphenate $#it that doesn't need hyphens. Yes, it's human relations. Then again, it's also English communications and computer operations.

  • Jacko
    Lv 6
    10 years ago

    You may find that wrapping emery cloth round the aluminium will stop it from slipping.

    I would get a strip and fold it in half, wrap it round the aluminium so that the emery side is in contact with the chuck AND the aluminium.

  • 10 years ago

    Are you using standard samples (dumbbell shaped samples) ? Because that shouldn't slip out.

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