# Force needed to bend beam

• mjonquiere

#### mjonquiere

HELP! how to calc the force needed to bend this fixed beam channel by 4mm at 'F'http://www.engineersedge.com/engineering-forum/attachment.php?attachmentid=1254&stc=1

#### Attachments

• CHANNEL BEAM WITH CENTRE LOAD.png
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It's not clear from the attached sketch what the dimensions of the channel are, what the length of the channel is, the location of the applied force, or if the channel is fixed at one end only or at both ends. Without additional information, advice can't be given.

Also, what the material is.

Hi All,
thanks for feed back. I am after a formula to find what force (F) the beam can withstand before plastic deformation and what force (F) caused it to bend by 4 mm.
It's a fully FIXRED beam fixed both ends, the difficulty for me is that its not a normal square beam it's a channel section. attached is a better drawing but its the formulas I'm really after.

#### Attachments

• Untitled.png
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Hi All,
thanks for feed back. I am after a formula to find what force (F) the beam can withstand before plastic deformation and what force (F) caused it to bend by 4 mm.
It's a fully FIXRED beam fixed both ends, the difficulty for me is that its not a normal square beam it's a channel section. attached is a better drawing but its the formulas I'm really after.
It's worse than that, I'm afraid.

The beam has a structural discontinuity at mid span with that notch in both flanges. You can't apply the regular beam formulas because they are derived assuming that the beam is continuous between supports with constant section properties. You can analyze this beam to determine the deflection and the stress, but it's more than just plugging numbers into a formula.

Are you looking for an order of magnitude estimate or something better? I think you need a numerical simulation to calculate it reasonably accurately. It's pretty involved. You are missing the dimensions of the notch in the drawing.

I'm guessing I could bend it by stepping on it in the center with both ends supported, but that's just a gut feeling