1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Buckling of a short structure

  1. Jun 2, 2010 #1
    1. The problem statement, all variables and given/known data

    Finding the critical buckling load of a really short column with wide cross section (is it still considered a column?)

    E = 22 GPa
    Yield: 300 MPa
    Load: 28N
    thickness: 0.226 mm
    I = 670706.51 mm^4 (is this right?)
    Load Applied Area (as indicated by white arrows): 190400 mm²


    I understand from http://www.engineersedge.com/column_buckling/column_ideal.htm that I should be applying Johnson's Formula.
    2. Relevant equations

    Euler Buckling :


    Johnson's Formula


    3. The attempt at a solution

    Using Johnson's formula, I've found out the Critical Buckling Load (Pcr) is 57119986 N

    I know this is a really short structure with a wide cross sectional area so naturally the Pcr will be bigger but could someone please verify my method?
    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Jun 2, 2010 #2


    User Avatar
    Science Advisor

    I don't think that will work. Typical buckling problems assume a deflected shape, which you won't get.

    The issue is not that it is short, but that it is thin-walled. Roark gives an idea for thin-cylindrical tubes, but not thin-rectangular tubes. I will quote his paragraph, 12.3 Columns and other Compressions Members
    My best guess would be to perhaps run a really good buckling model in ANSYS/Nastran and give it a good safety factor.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook