Associative (polygon) faces in Adv. Simulation

[NXLars]

Hi,

I'm currently investigating the possibilities of setting up FE-data (nodes and elements) to my automated CAD-models. My models are built in a way that allows surfaces to "come and go" depending on which final form the model shall describe. My method ensures that a certain feature of my model always is described with the same face (same surf. ID) every time, regardless of the shape of my final model.

However, when I create my .fem models I can't rely on my polygon geometry to behave in the same manner. Every time a surface/feature is added it get's a new (polygon) face ID even if it previously was found in the polygon geometry.

For example:
1. Create a box with a fillet on one edge.
2. Mesh the filleted box (shell mesh on the surfaces).
3. Return to the model and suppress the fillet.
4. Update the mesh (which works since most of the meshed surfaces still exists).
5. Unsuppress the fillet (fillet face still has the same face ID as when it was created).
6. Update the mesh (which now lacks the mesh on the previously meshed fillet surface...).

Is there another way to approach this so that the fillet in the example will be meshed in point 6? Is this prehaps working in more recent versions of NX?
I use shell mesh due to the fact that the different surfaces in my model well represents the areas where different mesh sizes is used.

NX 6.0.5.3

Thankful for any suggestions!

Best regards
/Lars

 

[petulf]

Hi Lars,

I can confirm the same behavior in NX8.0, the polygon face id changes each time the polygon is regenerated. What is needed is a way of automatically adding polygon faces to a mesh depending on som attribute criterion like name, color and so on. Maybe a journal could be of use here, one that adds faces to either CAE groups or meshes directly depending on for example a face color.

There is also a batch meshing program available for nx, but a quick look shows that its more at aimed att meshing entire parts and not for automating element size definitions on a single part.

 

[NXLars]

Hej Petter,

Thanks for your ansver. I assumed that this was the general behavior and that I would have to adress this in another way, although I was hoping for improvement in later versions of NX.
Now that you've confirmed the same behavior in later versions of NX I can, with more effort, look into another approach without feeling that I'm solving an already solved issue.

/Lars

 

[Helrezer]

This behavior in versions prior to NX8.5 was due to the way that polygon bodies were updated. In NX8.5, the update process was modified so that only modified faces get changed. This improves the update process and helps with the meshing updates. I have not checked for face IDs since I do not use them.

Marilyn Tomlin
Siemens PLM Software