von Mises or Equivalent stress for Beam Elements

[SirKickAxe]

Are there analytical expressions for computing von Mises or a form of equivalent stress for Beam elements similar to the ones in continuum elements? For an engineering application problem, I want to make sure that this von Mises/equivalent stress is less than yield stress to make sure structure is safe. 

I found some discussion here: 

http://forums.autodesk.com/t5/simulation-mechanical-and/von-mises-beam-stress/td-p/3685564

But nothing meaningful came out of it.

[AstroJohnPE]

Hi SirKickAxe,

The basic equation for von Mises stress is given in many text books and in the Help documention. The form from the documentation is this:

In the absence of torsion and shear stresses, the von Mises stress equals the worst stress given for beam elements, where you can think of the axial stress in the beams as Sx, and all of the other terms are 0.