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Homework Help: Percentage saving in weight of sloid shaft Vs hollow shaft

  1. Mar 8, 2009 #1
    I have calculated the external diameter and the solid shaft is to be replaced by a hollow shaft whose internal diameter equals 60% of the external diameter, the length, material, and maximum shear stress remaining unchanged.

    How can I calculate the percentage saving in weight?
    What are the equations that are relative to this?

    Thank u for ur help
  2. jcsd
  3. Mar 8, 2009 #2


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    Welcome to PF!

    Hi adam333! Welcome to PF! :smile:

    Hint: volume = cross-section-area times height …

    so how much is the cross-section-area reduced? :wink:
  4. Mar 8, 2009 #3


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    adam333: For the hollow versus solid shaft, hold applied torque and maximum shear stress constant, and set inside diameter of the hollow shaft equal to 60 % of the outside diameter of the hollow shaft. List relevant equations, and show your work.
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