The selected regions can not be meshed automatically (How to partition?) 3

[mdama]

Hello all
What is the best way to partition the model (

https://www.dropbox.com/s/ezd76qaiu7e1h37/1.png?dl=0)

to be able to get
hex shape mesh (structured or sweep)? The model has pores on top.

Thanks
Mohsen

 

[DanStro]

I am still pretty new at this but your model looks like it can be a good candidate for sweep (from the bottom surface to the top). But you might need to use Bottom-Up methods to get it to work. You should look at the help for that method. It has a pretty good tutorial on using them, just search the help for "An example including bottom-up meshing techniques" and it should come up.

Han primo incensus

 

[Mustaine3]

Based on the image I would say, that one partition might be enough. Split the part at that face were the holes end inside the part. So you have an upper cell with the holes and the lower cell with no holes.

Since the diameter of the holes is quite small, you might end up with a fine mesh. Or you allow wedge elements to transition from small elements at the holes to larger far away.

 

[mdama]

Thank you DanStro
I will try it.
.................................................

Mustaine3

Thank you so much. As you said, I created partition with "Extend face" for the face with holes. The color changes to yellow (

https://www.dropbox.com/s/fcgcqbfgr6x8gsf/yellow.PNG?dl=0)

but
when I mesh it using hex shape, It gives me error as you see here (

https://www.dropbox.com/s/3ze6lppme6pd2q4/error.PNG?dl=0).

Any suggestions would be appreciated.

Mohsen

 

[Erik Panos Kostson]

It looks like the seed/element size is too coarse for the part with the holes. Try using a much smaller seed so that you get say 6 elements around the circumference of the holes (use HEX 20/C3D20 elements also so you can capture the curvature), then sweep it.

 

[mdama]

Thanks Erik
Even when I refine the mesh for the partition with holes, some elements get unstable as you see here (

https://www.dropbox.com/s/1b0f9fevbx1d6z4/refinemesh.PNG?dl=0).

I attach the CAE file (

https://www.dropbox.com/s/10nbe5pyvnrf3c6/diatom.cae?dl=0)

with .jln file (

https://www.dropbox.com/s/78ceirpkyqie9yx/diatom.jnl?dl=0.

Any suggestions would be appreciated in advance.

Thanks

 

[Erik Panos Kostson]

It looks like you have managed already, but here goes anyhow.

If the global seeds go down to 0.0001, and then a medial axis algorithm is chosen and setting the sweep directions to go from top (hole part), to bottom (base/legs), then it meshes ok.

Of course other settings, like to assign also local seeds (in problematic areas like some holes, shown in the image), could do as well. So this is not the only way, just one of the ways.

 

[mdama]

Dear Erik
I use extend face (hole plane)to partition it. I changed the seeds to 0.0001 with medial algorithm but still I get error "the highlighted regions failed to mesh" which is the hole and the plane containng holes. Would you please upload the .cae file here?

Thanks a lot

 

[Erik Panos Kostson]

The model you sent.

- Go to Model-1 (not Job1)
- Go to the mesh module
- Choose Part-1
- Go to Seed/Part in the main menu
- Set global seed to 0.0001 (instead of 0.00098)
- Open Mesh/Control from the main menu, to set mesh controls
- Select all of the parts/cells, and press OK
- Choose Medial Axis alg. with the min. mesh transition option ticked
- Finally in the main menu, go to Mesh/Parts and press OK.

 

[mdama]

Yes, I did that (0.0001) but still gives me error "The highlighted regions failed to mesh". !!!

 

[mdama]

The problem is the plane with holes.... I want to mesh it with hex...

 

[Erik Panos Kostson]

If you did exactly that it should work (does when I do it). Not sure why. Cannot send files - cannot save in node limited demo version.