Dealing with local coordinate systems and bearing forces

Hello everyone, I hope you’re all doing fine!

After some time away from structural analysis, I returned to PrePoMax and gladly found amazing new features in which the local coordinate system shines the most for me. To try this new tool, I decided to create a simple “bolted” joint with some RBEs simulating the connection and tried using a local coordinate system to extract the forces from the middle hole so I could use them for hand calculations such as bearing and tear-out margins of safety.


In this small adventure, I faced the first issue: I could not assign a local CSYS to random nodes that had no loads or BC applied to them. Is there any way to force a *TRANSFORM card in some random nodes? I did a workaround using a dummy load in the local CSYS for the nodes I wanted to transform.

With the coordinate system working, I expected to read non-zero forces in the local Y direction. Here the next challenge showed up: Since the “totals” command does not work for local CSYS, I had to extract the sum from the history output in Excel:

This is not so practical for a single hole, and probably it would scale up for very complex joints. Therefore, I would like to ask if there is a better workflow out there for this type of problem!

Best regards,
Lucas.

It would be best to write a python script to do the post-processing for different holes.

That’s a good idea! I wonder if it would be possible to transform the total forces output by calculix in the PrePoMax post-processing… it would help a lot as well. But for now python and/or Excel work fine.