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Domain Recognition by COMSOL
Posted Jul 17, 2012, 1:53 p.m. EDT Geometry, Materials Version 4.3 2 Replies
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Hi,
I import a DXF file to COMSOL. But when I assign materials to my imported object, COMSOL cannot recognize the domains in the object. What COMSOL selects are actually the boundaries instead of the enclosed solid.
I use measurements to check whether COMSOL can define the domains, it shows that COMSOL has no problem in recognizing all the domains of the imported object. But I don't know why when it comes to materials, it will have this problem. Can somebody help me out?
Thanks a lot!
I import a DXF file to COMSOL. But when I assign materials to my imported object, COMSOL cannot recognize the domains in the object. What COMSOL selects are actually the boundaries instead of the enclosed solid.
I use measurements to check whether COMSOL can define the domains, it shows that COMSOL has no problem in recognizing all the domains of the imported object. But I don't know why when it comes to materials, it will have this problem. Can somebody help me out?
Thanks a lot!
2 Replies Last Post Jul 18, 2012, 1:05 p.m. EDT
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Posted:
1 decade ago
Hi
DXF is not a very well normalised protocol for drawings or 2D objects, therefore, often there are incomplete loops / poly-lines or missing edges in the drawings, these can be very small, but still deteced as anomalies by COMSOl, sometimes by using a lower resolution COMSOL manages to knit the lines together to form surfaces (domains in 2D)
other times you might select a series of edges and creae a "solid" therefrom manually in the geoemtry sequence
One way to better identify how COMSOl has translated the geometry is to use the selection list and see how COMSOL sorts the domains, boundaries etc.
Once passed the "finish" line in the geometry nodes, you have the FEM "Entities" as COMSOl identifies them, thereafter you can easily assign materials, physics and BC conditions to domains and boundaries.
Note that materials properties can be assigned to either domains or boundaries, and if you need material properties on both domains and boundaries (because you use some thin layer physics on some boundaries) then you might need to call in 2x the same material, once for the domains and once for the boundaries (see the selection list)
--
Good luck
Ivar
DXF is not a very well normalised protocol for drawings or 2D objects, therefore, often there are incomplete loops / poly-lines or missing edges in the drawings, these can be very small, but still deteced as anomalies by COMSOl, sometimes by using a lower resolution COMSOL manages to knit the lines together to form surfaces (domains in 2D)
other times you might select a series of edges and creae a "solid" therefrom manually in the geoemtry sequence
One way to better identify how COMSOl has translated the geometry is to use the selection list and see how COMSOL sorts the domains, boundaries etc.
Once passed the "finish" line in the geometry nodes, you have the FEM "Entities" as COMSOl identifies them, thereafter you can easily assign materials, physics and BC conditions to domains and boundaries.
Note that materials properties can be assigned to either domains or boundaries, and if you need material properties on both domains and boundaries (because you use some thin layer physics on some boundaries) then you might need to call in 2x the same material, once for the domains and once for the boundaries (see the selection list)
--
Good luck
Ivar
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Posted:
1 decade ago
Thank you, Ivar!
Problem solved!
Chloe
Problem solved!
Chloe