Let's assume that your beam is oriented longitudinally along the x-axis and that is subjected to a load in the y-direction that produces a bending moment around the z-axis.
Then, after running your simulation, you need to extract the S11 stresses in the section of your interest.
I hope it helps.
Best regards,
Ramiro
Ps: here you can find a video describing in more detail the bending on beams:
Thanks for your prompt response, if beam is oriented longitudinally along the z-axis and that is subjected to a load in the y-direction and produce x-axis moment, then I should extract S22 streess, right?
Let's simplify the problem. Consider a beam as a 1D problem, where your main direction is the longitudinal axis. As a consequence, you will have normal stresses in that direction (and depending on the load, shear stresses in the perpendicular direction). Due to the pressence of bending, in a given cross-section of your beam, you will have one portion working under compression and the other in tension. This variation will be linear in the elastic range.
Coming back to your problem, if your beam is oriented along the z-axis (your main axis for the 1D case), then, the stresses that you are interested are S33.
Please, find attached a quick scketch to put my words into a graph.