Learning Forum

[Bassemaa]

I am trying to read the angle of twist at the end of a beam under torsion. I used "User-Defined Result" with the expression RX.

The problem is the target beam is not parallel to the global X-axis. It is a part of a bigger structure and is at an angle. The results are way off the expected value, because - as far as I know - the results from the RX expression is related to the global coordinate system.

I have defined a local coordinate system with the new X-axis parallel to the beam, but I can't assign that new coordinate system to the user-defined result.

Oh it is a line beam model (BEAM188). Is there a way to solve this?

[Rohith Patchigolla]

One option is to change the nodal orientation of the nodes attached to this beam based on the new local co-ordinate system (which has X axis along the beam). You can do this using "Nodal Orientation" object (RMB on Static Structural --> Insert --> )
Then you will get the correct twist result when plotting the UDR using RX.
Hope this helps.
Best regards Rohith

[Bassemaa]

Thanks I am using Mechanical and workbench, so I can't manipulate element orientation. I suppose their orientation is correct because the line model is done with SpaceClaim (?)
Is there a way to change the coordinate system for the output of RX? It doesn't seem to accept other coordinate systems but the global one

[Bassemaa]

It turned out that the nodal coordinate system matches the global by default.
I managed to solve the problem with NMODIF command to redefine the nodal coordinate system and rotate it to the beam angle, then point the RX solution to the solution coordinate system SOLU.
Thanks again!