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!

Structures. column theory, Buckling

  1. Dec 11, 2008 #1
    1. The problem statement, all variables and given/known data

    the question is in the picture.
    the rectangular steel bar shown supports a concentric load of 13000lbf. Both ends are fixed. If te modulus of elasticity is 29x10^6 lbf/in^2, what is the maximum length the rod can be without experiencing buckling failure?

    2. Relevant equations

    3. The attempt at a solution

    what I got was 81.3365. but I am not sure.
    moment of inertia I got .1953125 from the cross section and just used Pcr = (I*E*(pie)^2)/(K*L^2) used .65 for K coz its fixed fixed.

    Attached Files:

    • jj.jpg
      File size:
      33.4 KB
  2. jcsd
  3. Dec 11, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Your calculation for the moment of inertia is incorrect. I don't know what formula you used, but you should use the Moment of Inertia of a rectangular bar about its weakest axis. Also, your buckling formula is incorrect, the K neeeds to be squared also, and K (ideal case) is 0.5 for a fixed-fixed column.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Structures. column theory, Buckling