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Homework Help: Calculate the stress in the duralumin rod

  1. Feb 5, 2015 #1
    1. The problem statement, all variables and given/known data
    a duralumin rod of 50mm diameter is a loose fit inside a mild steel tube of 60mm outside diameter. if the steel tube is turned down to 55mm diameter over one half its length, calculate the stress in the duralumin rod and the stress in each portin of the tube due to an akial load of 20KN. both rod and tube are the same length. E for steel=196GN/m^2 and E for duralumin = 126GN/m^2.

    2. Relevant equations
    force=stress in duralumin*area of duralumin+stress in steel*area of steel
    strain in steel=strain in duralumin

    3. The attempt at a solution
    stress in duralumin=load/area of duralumin
    and im stuck any help plz
  2. jcsd
  3. Feb 5, 2015 #2


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    Education Advisor
    Gold Member

    Welcome to Physics Forums.

    Are you sure you reported the full question correctly? Or, more to the point, are you sure you reported all of it? I'm interested in why you need E for the two materials.

    For example: It is not clear from what you stated if the force is applied to just the tube, just the rod, both equally, or just what.

    Anyway, a naïve reading would suggest you simply have two different areas for the cross section of the tube. So the stress just has two values.
  4. Feb 6, 2015 #3
    yes thats the whole question as it was given to our class.
  5. Feb 6, 2015 #4
    i think my attempt above was wrong(wrong path)
  6. Feb 6, 2015 #5
    i think my attempt above was wrong(wrong path)
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