1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bending Moments

  1. Dec 10, 2013 #1
    1. The problem statement, all variables and given/known data

    Hollow circular beam with outside diameter 350mm, and wall thickness of 60mm

    E=60 Gpa

    beam length 2m

    Force applied to beam at midpoint of beam (1m from each end)

    F=200KN

    Force applie from the Top down, Ra , and rb from bottom up


    2. Relevant equations

    Used o(bending)=My/I





    3. The attempt at a solution

    Got I correct as 599.29x10^-6(m^4)

    I think the bending moment is 100knm, but put in 50knm(wrong)

    I was wondering if y=0.175(half of outside diameter in metres)

    i got 14.60MPA(10^9) by doing, 50,000[bending moment]*0.175[y]/599.29*10^-6


    When replacing 50,000 with 100,000 i get 29.201MPA, and for the microstrain i get:

    E=65*10^9=29.201221*10^6/strain

    rearrange for strain

    strain = 29.201*10^6/65*10^9 = 44.92495067*10^ -5 or 44.92 microstrain
     

    Attached Files:

    Last edited: Dec 10, 2013
  2. jcsd
  3. Dec 10, 2013 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    y is measured in meters, not meter^2.

    Bending moment is measured in N-m

    You need to brush up on units and how to calculate bending moments.
     
  4. Dec 10, 2013 #3
    that was a mistake, an editing error

    as later shown, y=0.175mm, ( which is the half of outside diameter )

    could you eloborate on what i need to brush up on, where i can attain this information?
     
  5. Dec 10, 2013 #4

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Add to the list above, need to work on metric system. Half of 350 mm is 175 mm, not 0.175 mm (which is a teeny-tiny measurement)

    Working out bending moments starts with drawing a free-body diagram of the beam and figuring out the loads.

    Once the FBD is in static equilibrium, you can construct the shear force and bending moment diagrams for the beam.

    By inspection of the beam, it's easy to see that Rl = Rr = 100 kN. You should be able to figure out the moment from this information.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Bending Moments
  1. Bending Moment (Replies: 2)

  2. Bending moments (Replies: 4)

  3. Bending Moments (Replies: 1)

  4. Bending Moments (Replies: 1)

  5. Bending moment (Replies: 3)

Loading...