Rigid body and moment

Kaspars

Hello everyone!
Could someone give me some tip - when rigid body is being used (CCX), how do you set a moment/torque on a reference node who does not belong to any line or shell?

Andrea

RBE if you need a rigid behaviour of a surface or body.
Ref Node if you want to apply forces or translational constraints to the RBE
Rot Node if you want to apply moments or rotational constraints to the RBE

Attached picture: a force is applied to a surface by Ref Node - locking the 2nd DOF of the Rot Node (rotation around the y axis) the face remains parallel to the opposite face

Kaspars

Thanks for the answer Andrea!
I tried to replicate your example, but unfortunately i did not understand something because if i add a moment in the end of cantilever beam, i should get constant cross section stress distribution in all the length (since the bending moment is constant). So far i have got only stress distribution which is similiar to one that comes only from a concentrated force.

If i restrain ROT NODE about Z axis than yes - i can force the ending surfaces to stay mutually parralel.
To understand wheather the results i get are +/- correct i used RSAPRO for comparison.

Andrea could you please correct my mecway file, so it would be easier for me to understand?

Andrea

Applying bending moment through the rot node the stress distribution is correct (see attached picture)

Kaspars

Thanks Andrea! Finally i understood how it works.

Previously i mistakenly thought that REF NODE rotates around ROT NODE and the distance between them is like a half a distance of a lever arm.