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View Full Version : Cantilever stress formula???

scottcomposites
03-18-2011, 07:12 AM
Is there a formula that anybody knows of that will help me calculate the deflection at the end of a square tube projecting 90 degrees from a vertical square tube support? I believe in engineers terms, this is solved by a cantilever stress formula (i think). If it helps, it would be one fixed (welded) end, one free end, with the free end supporting 300lbs of hanging weight. Nominal steel will be used but without being able to calculate the amount of deflection, I'm at a loss for what size or wall thickness to use. Any help would be great as all I have found concerning this issue is Cantilever Stress Formula for Fixed End, Free End I Beams. Any thoughts, opinions, suggestions would be hugely helpful at this point :help:

Fegenbush
03-18-2011, 08:44 AM
I believe what you are looking for are the Euler-Bernoulli Beam Equations. They are sometimes called the beam tables, since the equations are given in table form.

Here is the link for cantilever beams:

http://en.wikipedia.org/wiki/Euler%E2%80%93Bernoulli_beam_equation#Cantilever_b eams

300 lbs at the end of the cantilever, check. How far is the load from the weld? If you are going to use square tube, I can tell you the size and wall thickness to make that work.

In general, the inputs are: