[arehman1289]

Hello,
I am trying to import both a .stp and .iges file into Star CCM of a corrugated pipe. I make it in ANSYS Design modeller with 2 perfectly fine bodies (solid pipe domain filled with a fluid domain). However when I import it into Star CCM, i get a lot of pierced faces during the surface repair, and hence cannot mesh. I changed the Tessellation density to even very fine when importing but it doesn't make a difference. Also tried surface repair, and also tried changing the dimensions of the pipe.
I can also send the native .stp file if needed, but attached is a screenshot.
Please help.
Thanks
Abdur

cfd rola.JPG

[ashokac7]

Pierced faces are okay to mesh as they often occurs in surface mesh of complicated geometries. Only those blue ones, manifold edges and vertices are problematic. They should be zero. Do some surface repair tutorial.

[arehman1289]

Thank you for the reply.

Yes the blue ones are both zero, but the pierced faces arent. When I mesh it gives an error, if interfence between the faces. My pipe geometry is corrugated and really thin. Maybe thats why.

Im googling surface repair tutorials, but no luck so far. Any recommendation ?

[AndreP]

From my small experience StarCCM doesn't work well with .stl or .iges files!

Try to use a Surface Wrapper to deal with that, or even go back to your CAD software and try to export it to .x_t file, and try to do the Surface Repair again and check if you still have that many problems!

[me3840]

It's possible the surface aren't sewn correctly or during transfer a trimmed surface was not translated properly.


Can you post more up-close images with the geometry and a not-so-fine tesselation?

[arehman1289]

Thank you for the replies

@AndreP


The errors seemed to disappear all together with .x_t file extension. However I am making further geometries to test it. Hope it keeps working.

@me3840
There wasnt any trimming our sewing involved when making the geometry. It is just very thin 0.1mm corrugated pipes sweeped along a spline and filled with a fluid domain. If I increase the thickness of the pipe to 0.5mm, I have no problem importing it even with not-so-fine tesselation. Attached is a close up, for comments on improving the geometry. I can also send the native .stp file if needed.

Capture.JPG

[AndreP]

I don't know why, but I've seen a lot of people having problems with .step and .iges files!

I always use .x_t solid files to reduce the chances of compatibility problems!

Glad I could help you!

[Maddin]

I also use STL always. May the CAD import can help you more but the issue is not at CCM. It's not a import issue, it's a export issue!

[arehman1289]

Yes the issue is with exporting, not importing.

[Maddin]

Possible the mesh creator makes trouble cause of the size but during importing you can define the scale factor of the import.
I would try to make the pipe factor 10 bigger and import it with an factor.

[arehman1289]

So are you saying I should scale down the geometry for easy meshing ?

At the moment I am using a simple surface remesher, polyhedral and prism layer mesher. The pipe geometry is about 0.7m long. I am using a base size of 8mm with some custom controls. However the software always crashes after a couple of hours. I am using a HPC.

Is it because of the old version I am using v11.04 ? Any advice's on how to mesh such heavy geometry quickly without having to restart due to it crashing ?

Thanks

[AndreP]

Try, just for once, use the Surface Wrapper (to fix any eventual geometry error that's causing a loop)!