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Two permanent magnets

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Hi,

I am new to using a FEM software and trying to model two permanent magnets and calculate the force they exert on each other. For this purpose, which module should I use? Also, are there any suggestions that you can give me about the boundary conditions or other things?

Thanks

8 Replies Last Post May 31, 2010, 7:57 a.m. EDT

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Posted: 2 decades ago Oct 16, 2009, 5:54 p.m. EDT
Hi Onur,
You can use magnetostatics module and get the force by surface stress tensor. You can read the horse shoe magnet exmple which is very similar to your case!
Hi Onur, You can use magnetostatics module and get the force by surface stress tensor. You can read the horse shoe magnet exmple which is very similar to your case!

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Posted: 2 decades ago Oct 16, 2009, 11:37 p.m. EDT
Hi Merlin,

Thanks a lot for your help. I forgot to add in my post that I want to do the simulation in 3D. But the same module doesn't exist for 3D. I couldn't find a good module for force calculation in 3D.

Thanks!
Hi Merlin, Thanks a lot for your help. I forgot to add in my post that I want to do the simulation in 3D. But the same module doesn't exist for 3D. I couldn't find a good module for force calculation in 3D. Thanks!

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 2 decades ago Oct 17, 2009, 5:07 p.m. EDT
Hi

The documentation of V3.5a acdcmodlib.pdf gives you a 3D model of a magnet and a steel block.

There is little difference between 2D and 3D for say, apart that a 2D is so much quicker to mesh and solve. In anycase it's always better to start off in 2D, once you get coherent results then a 3D model is there to check out fully.

Good luck
Ivar
Hi The documentation of V3.5a acdcmodlib.pdf gives you a 3D model of a magnet and a steel block. There is little difference between 2D and 3D for say, apart that a 2D is so much quicker to mesh and solve. In anycase it's always better to start off in 2D, once you get coherent results then a 3D model is there to check out fully. Good luck Ivar

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Posted: 2 decades ago Nov 24, 2009, 12:25 p.m. EST
Dear Ivan,

1. I am building a magnetic bearing in 3d to analyze force between the two permanent magnets and then electromagnets and can not find V3.5a acdcmodlib.pdf example . Can you please forward this model to me at
mark_murad@hotmail.com

Mark Murad
Cleveland State University
doctoral Student
office 216 687 2561
Cell 216 244 9713
Dear Ivan, 1. I am building a magnetic bearing in 3d to analyze force between the two permanent magnets and then electromagnets and can not find V3.5a acdcmodlib.pdf example . Can you please forward this model to me at mark_murad@hotmail.com Mark Murad Cleveland State University doctoral Student office 216 687 2561 Cell 216 244 9713

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 2 decades ago Nov 27, 2009, 3:43 p.m. EST
Hi

You should have the acdcmodelib.pdf in your doc directory of COMSOL, check p24 and thereafter

Good luck
Ivar
Hi You should have the acdcmodelib.pdf in your doc directory of COMSOL, check p24 and thereafter Good luck Ivar

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Posted: 1 decade ago May 31, 2010, 6:57 a.m. EDT
Hello.

i am zeeshan umar, doing MS Computational Engineering from University Rostock Germany, Actually i am doing the same project that i think already done. can you help me.
Hello. i am zeeshan umar, doing MS Computational Engineering from University Rostock Germany, Actually i am doing the same project that i think already done. can you help me.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago May 31, 2010, 7:07 a.m. EDT
Hi

within my limited time I can give some support, but I can mainly help you find where to look. Really when starting with COMSOL one should run through the examples in the doc, and reread the doc 2-3 times, as there is very much in there (I say ALL Physics in fact) but rewritten slightly differently from how we have been teached, to be dapted to COMSOL methodology and notation, that is doing a very good job unifying several domains tha should have been treated the same way for 50+years now, but for historical reasons have their own long-living habits and traditions.

I know it's time consuming, and often we want to solve our own problems to start with, but its worth to do our training first, and we have all passed through that stage I believe, I also highly recommend to take a few of the 1 day Comsol courses, I learned a lot during these sessions, boith the notations, methodology and the COMSOL tricks "how to use".

have fun Comsoling
Ivar
Hi within my limited time I can give some support, but I can mainly help you find where to look. Really when starting with COMSOL one should run through the examples in the doc, and reread the doc 2-3 times, as there is very much in there (I say ALL Physics in fact) but rewritten slightly differently from how we have been teached, to be dapted to COMSOL methodology and notation, that is doing a very good job unifying several domains tha should have been treated the same way for 50+years now, but for historical reasons have their own long-living habits and traditions. I know it's time consuming, and often we want to solve our own problems to start with, but its worth to do our training first, and we have all passed through that stage I believe, I also highly recommend to take a few of the 1 day Comsol courses, I learned a lot during these sessions, boith the notations, methodology and the COMSOL tricks "how to use". have fun Comsoling Ivar

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Posted: 1 decade ago May 31, 2010, 7:57 a.m. EDT
Hi,

you are right, i already done some example. but the problem is that, i am just confuse in how to select the equation for the magnetic field and how can i start it. because there is no such gud material on web site.
ya i have to use the 3D, and there is no Magneticostatic solver. what can i do...
Hi, you are right, i already done some example. but the problem is that, i am just confuse in how to select the equation for the magnetic field and how can i start it. because there is no such gud material on web site. ya i have to use the 3D, and there is no Magneticostatic solver. what can i do...

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