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Homework Help: Structural Analysis - Trusses

  1. Jul 23, 2010 #1
    1. The problem statement, all variables and given/known data
    Below is a truss system, use the point method to solve for all forces within the trusses.

    http://tinypic.com/view.php?pic=25i2dma&s=3

    my question, If I take pin F then I have 4 trusses, 2 of them known(FE, FD) and 2 unknowns(GF, CF). exactly what should I do with truss GF and FC, they have forces in x and y axis.

    2. Relevant equations



    3. The atthis is what I've found so far
    http://tinypic.com/view.php?pic=2q9ig05&s=3
    FDE=2.6 (T)
    FFE = 3 (C)

    http://tinypic.com/view.php?pic=f52428&s=3
    FCD = 2.60 (T)
    FDF = 1 (T)tempt at a solution
     
  2. jcsd
  3. Jul 23, 2010 #2

    PhanthomJay

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    Gold Member

    At F, solve for the member forces under the known x component of force from FE, then solve for the member forces under the known y components of force from FE and FD, and then add the results together. Also, your forces in DE and FE are not right, you seem to have assumed a 30 degree angle, which it is not.
     
  4. Jul 24, 2010 #3
    oh ok thanks.
     
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