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#1 2019-05-15 04:17:46

tienbk95
Member
Registered: 2019-05-15
Posts: 3

Mesh a model

hello everyone. when I make a model is a hemisphere with hollow, I want to mesh it by C3D8R element type. But I can't do it in Salome Meca.
How can I do to mesh model like that image which I attached below.
I glad when receive a help.


Attachments:
Capture1.PNG, Size: 76.95 KiB, Downloads: 30

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#2 2019-05-15 06:36:33

mecour
Member
From: Ostrava (Czech)
Registered: 2011-04-04
Posts: 93

Re: Mesh a model

Hello,

meshing of such shapes with hexahedral elements is not its strength. Here you have only 2 circles as edges, it is necessary to add more. You can partition the shape with some planes in geom module to get more surface edges. Then the hexa mesh is possible.

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#3 2019-05-15 10:51:11

tienbk95
Member
Registered: 2019-05-15
Posts: 3

Re: Mesh a model

Thanks Mecour very much. I try to partition but the model always has face with 3 sides, so I can't mesh with C3D8R element type.when I compute, the monitor has error: " unexpected geomery. Face must have 4 sides but not 3.
You can see the model which I partitioned below. and you can help me with this model?
I look forward your reply.


Attachments:
1.PNG, Size: 34.54 KiB, Downloads: 19

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#4 2019-05-16 12:25:06

mecour
Member
From: Ostrava (Czech)
Registered: 2011-04-04
Posts: 93

Re: Mesh a model

Hello,

I tried more strategies but unfortunately I am not able to create such mesh as you want. What I know about hexahedral meshing, there is no general algorithm as for example delauay for tetrahedral meshing. So every software (especially commercial) uses own internal algorithm to produce hexahedral mesh. There are only few opensource hexahedral mesh generators.
My strategy is using tetrahedral mesh in such curvilinear shapes and sometime is good to use the quadratic mesh to get better results.

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#5 2019-05-17 09:11:09

tienbk95
Member
Registered: 2019-05-15
Posts: 3

Re: Mesh a model

Thanks for your reply. I hope you are always healthy and successful.

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#6 2019-05-20 16:07:40

Nicolas
Member
From: EDF R&D Clamart
Registered: 2007-11-29
Posts: 83
Website

Re: Mesh a model

Here is one solution. The main difficulty is the edge that générâtes the sphères. It implies a translation for the partition.


Attachments:
hemisphere.py, Size: 5.21 KiB, Downloads: 8

Gérald NICOLAS
EDF R&D
Responsable du logiciel HOMARD

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#7 Yesterday 15:38:49

Nicolas
Member
From: EDF R&D Clamart
Registered: 2007-11-29
Posts: 83
Website

Re: Mesh a model

If you can rotate the spheres, the influence of the generatrices disappears.


Attachments:
hemisphere.py, Size: 5.2 KiB, Downloads: 4

Gérald NICOLAS
EDF R&D
Responsable du logiciel HOMARD

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#8 Yesterday 18:20:25

mecour
Member
From: Ostrava (Czech)
Registered: 2011-04-04
Posts: 93

Re: Mesh a model

Hello,

thanks to Nicolas I also created quite similar mesh.  Thank you for this instructions. I always fight with hexahedral mesh at curvaceous shapes.


Attachments:
pic.png, Size: 341.41 KiB, Downloads: 3

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