FEA Hand Calculation Validation

[Saints-94]

I have ran an FEA analysis on part screenshot below. I wanted to do some hand calculations to validate the results. What formula should I use to calculate the stress?

 

[Dr.D]

Calculate the bending moment in the two beams (by symmetry, you should be able to assume that they are the same, assuming that the loading is otherwise symmetric), then use sigma = Mc/I to get the bending stress.

 

[JBA]

This is the same problem that Saints-94 subsequently entered On the Mechanical Engineering site as the "Tube Bending Stress" thread that we are now helping him with.
See that thread for the latest updates.