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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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Simulation of a Metallic CUBE

Posted May 10, 2011, 6:21 a.m. EDT RF & Microwave Engineering Version 3.5a 10 Replies

Cecil Chalmers
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Dear Users,
I am trying to simulate a gold nano cube in air. I have drew a 40nm cube from the draw menu. Then i enclosed by it by a spherical surface which contain air.
Now my question is that, how to smoothened the sharp corners (edges) of a cube?
Does the comsol automatically smooths its edges by enclosing it in a sphere or i have to do some trick?

Regards,
Cecil.
10 Replies Last Post Dec 4, 2015, 9:34 a.m. EST
Edgar Kaiser
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Posted: 1 decade ago May 10, 2011, 7:23 a.m. EDT
Hi,

in COMSOL you can do mathematical operations with your objects. You can add, subtract and do boolean operations.
So, you can use a boolean AND on your cube and a sphere that is a little smaller than the diagonal of the cube to cut the sharp corners away. There may be more options depending what exactly you want.

Cheers
Edgar
Hi, in COMSOL you can do mathematical operations with your objects. You can add, subtract and do boolean operations. So, you can use a boolean AND on your cube and a sphere that is a little smaller than the diagonal of the cube to cut the sharp corners away. There may be more options depending what exactly you want. Cheers Edgar
Cecil Chalmers
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Posted: 1 decade ago May 10, 2011, 9:03 a.m. EDT
Hi,
Many thanks for your reply.

I followed your method (if i am correct), i.e. 1st of all i draw a sphere, then a cube. The sphere is a little bit smaller than the diagonals of the cube. Then i went to the draw menu. I selected the "Create Composite Object" and there i took an interaction of both the sphere and the cube. I obtained the figure given in the attachment.
I don't know whether it is correct or not and also this figure is a mixture of both the cube and sphere. Will it effect the results?

Best Regards,
Cecil.
Hi, Many thanks for your reply. I followed your method (if i am correct), i.e. 1st of all i draw a sphere, then a cube. The sphere is a little bit smaller than the diagonals of the cube. Then i went to the draw menu. I selected the "Create Composite Object" and there i took an interaction of both the sphere and the cube. I obtained the figure given in the attachment. I don't know whether it is correct or not and also this figure is a mixture of both the cube and sphere. Will it effect the results? Best Regards, Cecil.

Attachments:

Edgar Kaiser
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Posted: 1 decade ago May 10, 2011, 9:44 a.m. EDT
Cecil,

your sphere diameter is still significantly smaller than the diagonal of the cube. I mean the space diagonal through the center not the diagonal of one of the faces. You can now play a little and grow the sphere until you get something that looks like a cube with kind of cut away corners.

At the end you must decide by yourself if the geometry meets your requirements and you will need to apply appropriate procedures to validate your FE model.

Cheers
Edgar
Cecil, your sphere diameter is still significantly smaller than the diagonal of the cube. I mean the space diagonal through the center not the diagonal of one of the faces. You can now play a little and grow the sphere until you get something that looks like a cube with kind of cut away corners. At the end you must decide by yourself if the geometry meets your requirements and you will need to apply appropriate procedures to validate your FE model. Cheers Edgar
Jeff Hiller COMSOL Employee

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Posted: 1 decade ago May 10, 2011, 10:27 a.m. EDT
Updated: 3 years ago Jan 5, 2021, 10:29 a.m. EST
If you are trying to fillet the edges (not just round the vertices) of your cube, you can achieve that by filleting a square in a workplane, extruding that, making two copies of that extruded object, moving and rotating them appropriately and taking the intersection of those three objects, see the attached screen shot.
If you are trying to fillet the edges (not just round the vertices) of your cube, you can achieve that by filleting a square in a workplane, extruding that, making two copies of that extruded object, moving and rotating them appropriately and taking the intersection of those three objects, see the attached screen shot.

Attachments:

Cecil Chalmers
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Posted: 1 decade ago May 10, 2011, 11:45 a.m. EDT
Jean,
I want the same model, which you showed me. Can you please explain it a little more (parameters etc) as i am using comsol 3.5a.
Thanks.

Regards,
Cecil
Jean, I want the same model, which you showed me. Can you please explain it a little more (parameters etc) as i am using comsol 3.5a. Thanks. Regards, Cecil
Jeff Hiller COMSOL Employee

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Posted: 1 decade ago May 10, 2011, 2:00 p.m. EDT
There's nothing to it, really. In a workplane you just create a square and fillet its corners. Then you extrude that shape; that gives you a square column with rounded edges. You make two copies and rotate them 90 degrees so that the three columns are aligned with the x,y, and z axes. Finally you move them so their intersection is the dice you are after, and take the intersection.
If you update to 4.1 I can send you the mph file.
There's nothing to it, really. In a workplane you just create a square and fillet its corners. Then you extrude that shape; that gives you a square column with rounded edges. You make two copies and rotate them 90 degrees so that the three columns are aligned with the x,y, and z axes. Finally you move them so their intersection is the dice you are after, and take the intersection. If you update to 4.1 I can send you the mph file.
Cecil Chalmers
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Posted: 1 decade ago May 18, 2011, 1:01 p.m. EDT
Hi jean,
I have now installed Comsol 4.1. Can you send me the mph file.

Thanks.

BR,
Cecil
Hi jean, I have now installed Comsol 4.1. Can you send me the mph file. Thanks. BR, Cecil
MicroXact
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Posted: 1 decade ago Oct 17, 2011, 4:07 p.m. EDT
Hi Jean,

Could you send to me a copy as well? I have made it to the point where intersection operation occurs

I have version 4.2.
Hi Jean, Could you send to me a copy as well? I have made it to the point where intersection operation occurs I have version 4.2.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 18, 2011, 7:03 a.m. EDT
Hi

follow the steps under the model builder geoemtry tab, of the dice.png picture, and you will find out ;)

--
Good luck
Ivar
Hi follow the steps under the model builder geoemtry tab, of the dice.png picture, and you will find out ;) -- Good luck Ivar
Jeff Hiller COMSOL Employee

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Posted: 8 years ago Dec 4, 2015, 9:34 a.m. EST
Update on this thread: Nowadays COMSOL includes a 3D fillet capability in the Design Module. See www.comsol.com/design-module
Best,
Jeff
Update on this thread: Nowadays COMSOL includes a 3D fillet capability in the Design Module. See http://www.comsol.com/design-module Best, Jeff

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