Reply To: Moment Reaction is large when large deflection is turned on

[peteroznewman]

Hi Adeleine,

It looks like the beams have about a 300×300 mm section.

I recommend you place a Csys about 600 mm away from the joint so that it cleanly cuts through the beam. Request the Reaction Force through that plane.  To transfer that force to another frame, create the same 600 mm long stub and apply that Reaction Force the end face. Assuming this model converges, you should ignore the stress in the stub near the cut end as it may show some disturbance from the cut boundary.

Transferring forces is cleaner than moments because the force is directly applied to nodes and as long as the coordinate frames have X, Y and Z pointing in the same directions in each model, the transfer will be correct.  Moments can’t be applied to nodes on solid elements, they have to be converted to forces first. The problem is if the origin of the coordinate system with respect to the cut face is not identical between the two models, the conversion of moments to force can introduce a huge scale factor error. This can’t happen when forces are transferred.