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Homework Help: Coefficient of linear thermal expansion of a composite bar

  1. Sep 19, 2005 #1
    question: a composite bar of length L=L1+L2 is made from a bar of material 1 and length L1 attached to a bar of material 2 and length L2.

    show that the effective coefficient of linear thermal expansion is :

    alpha= (a1L1+a2L2)/L

    [- alpha/a=coefficient of linear thermal expansion]

    i have no idea how to derive that equation, the only thing i no/learned from reading the book is that the equation for the coefficient of linear thermal expansion for one material is alpha=(delta L)/Lo(delta T)

    anyone who can show me/drop some hints would be greatly appreciated.

    thanks in advance
  2. jcsd
  3. Sep 19, 2005 #2

    Doc Al

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    Staff: Mentor

    Hint: The expansion ([itex]\Delta L[/itex]) of the composite bar is the sum of the expansions of each segment.
  4. Sep 19, 2005 #3
    ahhh...........that clearified me....i think i get it....thanks alot.
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