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Homework Help: Structural analysis stiffness method

  1. Sep 28, 2011 #1

    I need to solve this problem but with member 2 as L+e instead of L, and omit the load..

    Since I only see one degree of freedom, i don't know how to set up the matrix to solve for the 3 forces.

    I have K11 = EA/L + (EA/(L+e))cos2(30) + EA/L cos2(60) but since there is only 1 DOF and no loads, i don't have much to make a matrix equation with..

    I tried moving the roller to the right ecos(30) and trying to solve for the forces like that, but couldn't get much.. any ideas?
    Last edited: Sep 29, 2011
  2. jcsd
  3. Sep 30, 2011 #2
    I figured it out..

    AD = Adm + kD

    AD = 0

    K11 = EA/L + (EA/(L+e))cos2(30) + EA/L cos2(60) = 2EA/L

    Adm = PL/EA = ecos(30) --> P = EAe√3/2L

    --> D = √3e/4

    AR1 = Arm + FrD

    AR1 = EA√3e/4L
    AR2 = -5EAe/8L
    AR3 = EA√3e/8L
    Last edited: Oct 1, 2011
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