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[ICEM] Work with imported STL geometry

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Old   July 8, 2015, 02:31
Default Work with imported STL geometry
  #1
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Hello everybody,

Since I am new to ICEM, I hope you don't mind a little question. So far I have created a STL geometry with Blender and want to mesh it with ICEM now. I have two options to get my stl imported now:

Import STL geometry: ICEM only imports the curves which are necessary to describe the shape of the object. Curves can be , yes, curved.

Import STL mesh: ICEM imports the triangled mesh as I created it in Blender. There are no curves, only straight edges.

Please correct me if I'm already wrong with this!

I first tried to import only the STL geometry because I thought it was a "cleaner" way to do it. My STL was already patched in Blender, therefore I chose "Part names from file" in the STL import options and my patches show up as parts as expected.
Next I wanted to setup a curve mesh in order to define the mesh at an edge of my geometry (Mesh -> Curve Mesh Setup). The problem is I can't select any curve of my geometry. How do I make my imported geometry be recognizable by the mesh definition tools?
In the tutorials I found so far they always use the automatic feature extract function which I don't want to use because I already have a patched geometry.

If anyone knows any tutorials or can give me a quick step by step guide I'd be very grateful.

I also tried with the "Import STL mesh" option but didn't succeed so far. Any guides regarding this are also welcome.

Best regards and thanks in advance,

Kate
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Old   July 8, 2015, 09:54
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Hello,

I meshed my geometry without the curve mesh setup for now, for training purpose. I am still interested in a solution, however.

Next I tried to build 31 prism layers with an initial height of 1.8*10^-5 m and a total height of 0.02 m and set the values in the Global Mesh Setup menu accordingly. The Height ratio equals 3.5 (calculated by ICEM). This value seemed quite high for me. When I calculated it with numbers, I got an height ratio of 1.2 with the following heights:

Code:
0,000018
0,0000216
0,00002592
0,000031104
0,0000373248
0,00004478976
0,000053747712
0,0000644972544
0,00007739670528
0,000092876046336
0,0001114512556032
0,00013374150672384
0,000160489808068608
0,00019258776968233
0,000231105323618795
0,000277326388342555
0,000332791666011065
0,000399349999213279
0,000479219999055934
0,000575063998867121
0,000690076798640545
0,000828092158368654
0,000993710590042385
0,00119245270805086
0,00143094324966103
0,00171713189959324
0,00206055827951189
0,00247266993541427
0,00296720392249712
0,00356064470699655
The sum of these values is 0.021 m. I just can't find my mistake. And when I look at the mesh afterwards, I can see that the second layer is about 3 times as high as the first one. But the ratio is in the range of 1.1 (inspected visually) at the layers # ...27, 28, 29.

It would be very helpful if anyone could explain this.

Best regards, Kate

Edit: I have attached two screenshots to explain what I'm complaining about in a better way.
Attached Images
File Type: jpg firstlayers.jpg (25.6 KB, 2 views)
File Type: jpg all_layers.jpg (69.6 KB, 1 views)

Last edited by KateEisenhower; July 9, 2015 at 02:05.
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Old   July 9, 2015, 10:46
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Hello again,

I am still struggling with the two problems from the previous posts.
And I experienced another challenge today:
I have one part (object) which intersects with another one(side). At the object part I am growing a boundary layer and it works fine except for at the intersection line with the side part.
I want the prism layer go all the way to the intersection line while keeping the specified height (in a way you could even see the layers in the surface mesh of the side part)

Here are the steps I take:

1) Import Geometry -> Faceted -> STL -> take parts from file (my *.stl file is already patched)
2) Global mesh setup -> Global mesh parameters -> Global Element seed size -> Max element 0.5 -> apply
3) Prism Meshing Parameters ->
Growth law linear
Initial height 1.8*10^-5
Height ratio 7.327...
Number of layers 20
Total height 0.022
-> Apply
4) Part mesh setup -> object: prism checked, maximum size 0.01 -> Apply
5) Compute Mesh -> Volume Mesh -> Create Prism Layers checked -> Compute

The result I get can be explained best with the attached picture I guess.

Would be nice if anyone could comment on this.

Best regards,

Kate
Attached Images
File Type: jpg boundaryLayer_decreasingHeight.jpg (29.0 KB, 2 views)
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