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How do I add edges to the circumference of a disk?

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Basically I've modelled a tiny piezo disk and I need to provide in-plane stress and I'm doing that by making one boundary a fixed constraint and providing boundary load to the opposite boundary. Using the cylinder, I already got 4 edges along the circumference but this makes the boundaries too large. Can I create new edges somehow? I tried virtual operations but couldn't do it that way. I'd appreciate any help. Thanks!


2 Replies Last Post 14.01.2021, 12:41 GMT-5
Robert Koslover Certified Consultant

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Posted: 4 years ago 14.01.2021, 10:41 GMT-5
Updated: 4 years ago 14.01.2021, 10:49 GMT-5

If I understand you correctly, then your problem has to do with the way the geometry is/was created. A default circle (or cylinder) has 4 arcs to it. But you don't have to create it that way. For example, you can instead create a circle in a way that allows you to set how many arcs are used. Then you can make a cylinder by extruding that circle. To do this, in a workplane, create a circle in terms of a set of arcs or pie-wedges. This is possible because Comsol allows you to specify the angular range of the "circle," which is 360 deg by default, but you can specify a different value. For example, see the attached .mph file and a .jpeg screenshot. In this example, I used 60 deg arcs, then rotated and combined them to make a full circle composed of 6 arcs, instead of the usual 4. You can use the same technique to get as many arcs as you want.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
If I understand you correctly, then your problem has to do with the way the geometry is/was created. A default circle (or cylinder) has 4 arcs to it. But you don't have to create it that way. For example, you can instead create a circle in a way that allows you to set how many arcs are used. Then you can make a cylinder by extruding that circle. To do this, in a workplane, create a circle in terms of a set of arcs or pie-wedges. This is possible because Comsol allows you to specify the angular range of the "circle," which is 360 deg by default, but you can specify a different value. For example, see the attached .mph file and a .jpeg screenshot. In this example, I used 60 deg arcs, then rotated and combined them to make a full circle composed of 6 arcs, instead of the usual 4. You can use the same technique to get as many arcs as you want.


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Posted: 4 years ago 14.01.2021, 12:41 GMT-5

If I understand you correctly, then your problem has to do with the way the geometry is/was created. A default circle (or cylinder) has 4 arcs to it. But you don't have to create it that way. For example, you can instead create a circle in a way that allows you to set how many arcs are used. Then you can make a cylinder by extruding that circle. To do this, in a workplane, create a circle in terms of a set of arcs or pie-wedges. This is possible because Comsol allows you to specify the angular range of the "circle," which is 360 deg by default, but you can specify a different value. For example, see the attached .mph file and a .jpeg screenshot. In this example, I used 60 deg arcs, then rotated and combined them to make a full circle composed of 6 arcs, instead of the usual 4. You can use the same technique to get as many arcs as you want.

Hey Robert, thanks for the input. I couldn't open the mph file as I'm on 5.5 but I followed the steps and it worked like a charm. Would you also by any chance know how to extract the external impedance as seen by the disk? Thanks again!

>If I understand you correctly, then your problem has to do with the way the geometry is/was created. A default circle (or cylinder) has 4 arcs to it. But you don't have to create it that way. For example, you can instead create a circle in a way that allows you to set how many arcs are used. Then you can make a cylinder by extruding that circle. To do this, in a workplane, create a circle in terms of a set of arcs or pie-wedges. This is possible because Comsol allows you to specify the angular range of the "circle," which is 360 deg by default, but you can specify a different value. For example, see the attached .mph file and a .jpeg screenshot. In this example, I used 60 deg arcs, then rotated and combined them to make a full circle composed of 6 arcs, instead of the usual 4. You can use the same technique to get as many arcs as you want. Hey Robert, thanks for the input. I couldn't open the mph file as I'm on 5.5 but I followed the steps and it worked like a charm. Would you also by any chance know how to extract the external impedance as seen by the disk? Thanks again!

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