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Issue with fillet

Posted Feb 13, 2024, 7:49 a.m. EST 11 Replies

Raffaella Acquaviva
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Hello guys. I am Electronics Engineering student in Politecnico di Milano and I am using Comsol for my thesis project. I have an issue with the fillet, in particular I'm able to built it in the geometry butn when I form the union, it becomes a straight line. I cannot increase the radius of the fillet as the structure is in the order of few um. Is it possible to change the grid of the points used by Comsol to build the union? Does anyone have the same issue? Thank you so much, Raffaella

11 Replies Last Post Feb 15, 2024, 8:33 a.m. EST
Acculution ApS Certified Consultant
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Posted: 9 months ago Feb 13, 2024, 8:41 a.m. EST

Have you tried a different tolerance?

-------------------
René Christensen, PhD
Acculution ApS
www.acculution.com
info@acculution.com
Have you tried a different tolerance?
Edgar J. Kaiser Certified Consultant
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Posted: 9 months ago Feb 13, 2024, 8:41 a.m. EST

Raffaella,

I am not sure if this is the issue, but you could try to change the geometry units to µm instead of m.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Raffaella, I am not sure if this is the issue, but you could try to change the geometry units to µm instead of m. Cheers Edgar
Raffaella Acquaviva
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Posted: 9 months ago Feb 13, 2024, 10:57 a.m. EST

Have you tried a different tolerance? Hello René, yes I tried to change the absolute tolerance from nm to fm but nothing changes.

Thanks Raffaella

>Have you tried a different tolerance? Hello René, yes I tried to change the absolute tolerance from nm to fm but nothing changes. Thanks Raffaella
Raffaella Acquaviva
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Posted: 9 months ago Feb 13, 2024, 11:02 a.m. EST

Raffaella,

I am not sure if this is the issue, but you could try to change the geometry units to µm instead of m.

Cheers Edgar

Hello Edgar, I tried to change it too, but nothing works. It seems a sort of resolution problem depending on the dimension of the element that Comsol accepts as the lowest possible. In fact, if I modify the radius putting it equal to 300 nm, I see a sort of fillet (see my attatched screenshots).

Thanks, Raffaella

>Raffaella, > >I am not sure if this is the issue, but you could try to change the geometry units to µm instead of m. > >Cheers >Edgar Hello Edgar, I tried to change it too, but nothing works. It seems a sort of resolution problem depending on the dimension of the element that Comsol accepts as the lowest possible. In fact, if I modify the radius putting it equal to 300 nm, I see a sort of fillet (see my attatched screenshots). Thanks, Raffaella
Edgar J. Kaiser Certified Consultant
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Posted: 9 months ago Feb 13, 2024, 11:06 a.m. EST

I suggest you upload the model, so we can play with it.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
I suggest you upload the model, so we can play with it.
Magnus Ringh COMSOL Employee

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Posted: 9 months ago Feb 14, 2024, 7:10 a.m. EST

Hi Raffaella,

This is a visualization artifact. Go to the Mesh settings and set a small Maximum element size on the fillet edge. Then you will get a mesh that shows the true fillet arc.

Best regards,

Magnus

Hi Raffaella, This is a visualization artifact. Go to the Mesh settings and set a small Maximum element size on the fillet edge. Then you will get a mesh that shows the true fillet arc. Best regards, Magnus
Raffaella Acquaviva
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Posted: 9 months ago Feb 15, 2024, 5:08 a.m. EST

I suggest you upload the model, so we can play with it.

Hello Edgar, here uploaded my projest with the fillet built. When you form the union, you can see that the fillet change structure. Thanks a lot for your haelp. Raffaella

>I suggest you upload the model, so we can play with it. Hello Edgar, here uploaded my projest with the fillet built. When you form the union, you can see that the fillet change structure. Thanks a lot for your haelp. Raffaella
Raffaella Acquaviva
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Posted: 9 months ago Feb 15, 2024, 5:09 a.m. EST

Hi Raffaella,

This is a visualization artifact. Go to the Mesh settings and set a small Maximum element size on the fillet edge. Then you will get a mesh that shows the true fillet arc.

Best regards,

Magnus

Hello Magnus, thanks for the suggestion. I put as max element size 1e-9 m and min size of 0.5e-9 m. But the problem occurs before defing the mesh, when we form the union of the geometry. Kind regards, Raffaella

>Hi Raffaella, > >This is a visualization artifact. Go to the Mesh settings and set a small Maximum element size on the fillet edge. Then you will get a mesh that shows the true fillet arc. > >Best regards, > >Magnus Hello Magnus, thanks for the suggestion. I put as max element size 1e-9 m and min size of 0.5e-9 m. But the problem occurs before defing the mesh, when we form the union of the geometry. Kind regards, Raffaella
Edgar J. Kaiser Certified Consultant
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Posted: 9 months ago Feb 15, 2024, 6:54 a.m. EST

Raffaella,

as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing.

Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature.

This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL).

Cheers, Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Raffaella, as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing. Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature. This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL). Cheers, Edgar
Raffaella Acquaviva
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Posted: 9 months ago Feb 15, 2024, 7:42 a.m. EST

Raffaella,

as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing.

Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature.

This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL).

Cheers, Edgar

Hello Edgar, thanks for your advise. Now I'm able to see the mesh on the fillet too. Thank you so much and have a nice day! Raffaella

>Raffaella, > >as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing. > >Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature. > >This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL). > >Cheers, >Edgar Hello Edgar, thanks for your advise. Now I'm able to see the mesh on the fillet too. Thank you so much and have a nice day! Raffaella

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Magnus Ringh COMSOL Employee

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Posted: 9 months ago Feb 15, 2024, 8:33 a.m. EST

Raffaella,

as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing.

Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature.

This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL).

Cheers, Edgar

Hi Edgar,

Such an improvement is on our radar.

Best regards, Magnus

>Raffaella, > >as Magnus pointed out it is a visualization effect in the geometry, probably because you have very large ratio in the dimensions of the thing. > >Use an edge mesh for the fillet at the top of the meshing sequence, that properly resolves the curvature. > >This way the curvature will be accounted for in the calculation and it will be shown in the result plots. The artifact will remain in the geometry visualization, but you can ignore it. Of course it would be nice if the geometry visualization avoided such artifacts that can create confusion (pinging COMSOL). > >Cheers, >Edgar Hi Edgar, Such an improvement is on our radar. Best regards, Magnus

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