Torsion

[struggle66]

Hi Good Day Everyone,

I would like to ask a very simple question about torsion. I should go back to school or ask my senior but at this moment neither is possible for me .

My question is

Is my eq 1 & 2 correct?

 

[JedClampett]

You are fine with what you have. But you're missing a very important component called the "warping normal stresses." These cause (simulated) bending moments on your flanges. AISC has a publication that gives the graphs and constants to solve for these forces. Warning; it's pretty complicated.
You can approximate these forces by resolving your torsion into a couple (like you did) and applying it as a weak axis force to each flange.