# Why am I seeing a moment reaction at the supports for these beams in FEM?

Please observe the Finite Element model below, in ANSYS WorkBench, (Remote force behavior = Deformable).

Also, please take a lot at the force and moment reactions at the fixed supports. I couldn't understand that why am I seeing a moment reaction about Y axis at the fixed supports for both of the beams? I mean yes, for the reaction forces to be different from each other, it makes sense mathematically that that the beam which is relatively closer to the applied force will have more portion of that force passing through it. But why do the beams turn a little bit clockwise when the remote force is applied in this manner? And why do they generate a reaction moment at end of each of the beam?

Moreover, I have also conducted an analysis with a simple force passing through the centroid of the same scoped faces with the same value, and it neither generated any reaction moments nor the beams turned clockwise. So the question basically becomes that why would the force when applied somewhat closer to one of the beams would do so?

• How is your force connected to your beams? Ridigly? If so, I assume the link between the two beams produces the bending?
– Öskå
Oct 6 at 14:20
• It is written in the first line of the post that the remote force behavior is DEFORMABLE. Oct 6 at 14:30
• Unfortunately that doesn't mean much to me, but I'm pretty sure that the behaviour isn't the one you expect. Try the same on APDL where you would actually be sure of what's being done without the boxes.
– Öskå
Oct 6 at 14:32
• @RameezUlHaq For people who understand FEA and beam bending but don't use Ansys, "Remote force behaviour = deformable" means nothing. The pictures don't explain how the force is actually applied to the beams. Oct 6 at 15:54
• Deformable behavior = each of the nodes on each of the scoped faces can move independent of each other. Rigid behavior = each of the nodes (and hence each scoped face) cannot move independent and hence has to move somewhat altogether. I hope this was clear enough. Oct 6 at 16:21

Because both beams are loaded in the transverse directions. No matter the magnitude, the transfer loads lead to moments. If you didn't assign the transverse loads, then check your model for geometric irregularities or input mistakes.

Understand the causes of errors in FEM programs:

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• Why do you think a force of $10^{-3}$N in the X direction is anything more than a rounding error, compared with hundreds of N in the Z direction? Oct 6 at 15:55