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Homework Help: Very stuck on loads on a beam

  1. Jun 16, 2009 #1
    an i section beam 5 meters long, supported both ends,
    with a 2nd moment of area 120x10 ^-6 m ^4

    a depth of 250mm and a uniformaly distributed load of 20KN/m

    max bending moment
    min bending stress
    the radius of curvature of the beam where the bending moment is maxaimun ( E-210GPa)

    people i not got a clue, its some last min work thats been droped on me!

    any working or help would be amazing
  2. jcsd
  3. Jun 16, 2009 #2


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    Science Advisor
    Homework Helper

    Hello, the_karlos. You must list relevant equations yourself, and show your work; then someone might check your math. Look in your text book to find relevant equations.
  4. Jun 17, 2009 #3
    Hello there,

    If you don't have the theoretical knowledge required, just Google search 'DTBeam' and download the demo version. It will do all the required calculations for you.
  5. Jun 18, 2009 #4


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    Gold Member

    For real, it would take days just to explain the last question.
  6. Jun 21, 2009 #5
    should probably read
    I do not know what textbooks you use for the course, but Chapter IV of the classic book derives all the required equations above from first principles and has worked examples very similar to the simple case you mentioned.
    The reference should be easily available from your college/university library:

    Strength of Materials, Part I, Elementary Theory and Problems, D. Van Nostrand Company, 1st Ed. 1930, 2nd Ed. 1940, 3rd Ed. 1955
    or on Amazon:
    Last edited by a moderator: May 4, 2017
  7. Jun 30, 2009 #6
    it has been a while since i covered structural mechanics but im sure i can remember that the maximum bending moment occurs at the middle point of the beam and the calc should include (Ra x 1/2l) - (UDL x 1/2b x 1/4l) < try that and let me know how you get on

    Ra = reaction
    L = length of beam
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