Beam Bending, beyond the basics, a little

[mechdesign2k4]

Ok, I am fairly comfortable with beam bending equations for simple rectangles. However, I am totally confused on how to approach other cross sections... like a channel can someone help? Or point me to a good online instructional resource? I have googled all I can think of...


-Mark

 

[FredGarvin]

What else are you changing other than the cross sectional MOI?

 

[Mech_Engineer]

For simple beam bending calculations, all you have to do is calculate the MOI for the section. Whether its an I-beam or a circular tube, all of the beam equations are the same (although some stress distributions may change).

 

[mechdesign2k4]

Thanks! I must have been over thinking it. I was sort of approaching it as taking each side of the tube, and top and bottom, calculating MOI for each...and adding them together. Thanks for the help!

Great forum!

-Mark

 

[Mech_Engineer]

Thanks! I must have been over thinking it. I was sort of approaching it as taking each side of the tube, and top and bottom, calculating MOI for each...and adding them together. Thanks for the help!

That's pretty close to how you would calculate the MOI, see here: http://en.wikipedia.org/wiki/Second_moment_of_area

...but for common cross-sections like an I-beam, formulas for it's section properties have already been calculated in detail, you just have to find them. Here is one resource: http://www.efunda.com/math/areas/Common_Cross_Section_Index.cfm

 

[mechdesign2k4]

Thanks again!