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magnetic flux density

Posted Oct 21, 2013, 2:20 a.m. EDT 7 Replies

Labib Ehsan
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hello, i want to make a permanent magnet, and see the magnetic flux density norm using arrow surface. i found a picture of a magnet, see attached photo, but i need to know how i can make this, because i need similar magnets for another project. i've been trying different methods but so far it has been unsuccessful. please can someone help me.?

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7 Replies Last Post Oct 30, 2013, 2:42 a.m. EDT
Ralf Tschiesche
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Posted: 1 decade ago Oct 24, 2013, 9:44 a.m. EDT
Hello!
You can add an extra Ampere's Law in your MF or MEF model, select your magnet domain, switch the Magnetic field to Remanent flux or Magnetization and put in a value.
This will produce a Permanent magnet.
Ralf
Hello! You can add an extra Ampere's Law in your MF or MEF model, select your magnet domain, switch the Magnetic field to Remanent flux or Magnetization and put in a value. This will produce a Permanent magnet. Ralf
Muhammad Hamid Khan
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Posted: 1 decade ago Oct 25, 2013, 4:01 p.m. EDT
Hey Ralf...

Plz let us know that And if i want to implement halbach for 7 pieces of 16 x 4 mm, how can i assign field lines into and out of the paper?
And let us confirm that while applying amperes law, I should divide 16 x 4 into two pieces and assign each piece say 5000 A/m in magnetization in x and y? Kindly confirm that. And also that how can I assign flux lines into and out of the paper (I mean by that field lines from top to bottom and bottom to top assigning)...
And what material should i assign? Iron or material like NdFeb etc???

Plz let me know that, it will be ur great favour...
Regards...
Hey Ralf... Plz let us know that And if i want to implement halbach for 7 pieces of 16 x 4 mm, how can i assign field lines into and out of the paper? And let us confirm that while applying amperes law, I should divide 16 x 4 into two pieces and assign each piece say 5000 A/m in magnetization in x and y? Kindly confirm that. And also that how can I assign flux lines into and out of the paper (I mean by that field lines from top to bottom and bottom to top assigning)... And what material should i assign? Iron or material like NdFeb etc??? Plz let me know that, it will be ur great favour... Regards...
Ralf Tschiesche
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Posted: 1 decade ago Oct 28, 2013, 8:37 a.m. EDT
Hello!
You can use my example for a Halbach array; this is in 2D.
So I don't know, what do you mean with "flux lines in and out of the paper"...
In 2D this is not possible.
Ralf
Hello! You can use my example for a Halbach array; this is in 2D. So I don't know, what do you mean with "flux lines in and out of the paper"... In 2D this is not possible. Ralf
Muhammad Hamid Khan
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Posted: 1 decade ago Oct 29, 2013, 4:46 a.m. EDT
Hy Ralf, immense thanx for ur responce.

The figure is in accordance to my requirement but I cant open the comsol file because of later version.
Wish I could open it.
Let me know please that for NdFeB permanent magnet what should I use in Ampere's Law?

1) Remenant Flux Density
2) BH Curve
3) Magnetization
4) Relative Permeabilty

And on which basis I should use values to the recommended above way by u? Should I assign material as NdFeB or simply use iron? And kindly give me ur email.

Regards...
Hy Ralf, immense thanx for ur responce. The figure is in accordance to my requirement but I cant open the comsol file because of later version. Wish I could open it. Let me know please that for NdFeB permanent magnet what should I use in Ampere's Law? 1) Remenant Flux Density 2) BH Curve 3) Magnetization 4) Relative Permeabilty And on which basis I should use values to the recommended above way by u? Should I assign material as NdFeB or simply use iron? And kindly give me ur email. Regards...
Ralf Tschiesche
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Posted: 1 decade ago Oct 29, 2013, 5:57 a.m. EDT
Hello!
My version is 4.3b, as you marked above...
I use remanent flux density; rotating direction from piece to piece:
first piece: +1.2T in y direction, second piece: +1.2T in x direction, third piece: -1.2T in y direction and fourth piece: -1.2T in x direction and so on...
Other properties are sigma=1S/m and epsilon_r=1.
Ralf
Hello! My version is 4.3b, as you marked above... I use remanent flux density; rotating direction from piece to piece: first piece: +1.2T in y direction, second piece: +1.2T in x direction, third piece: -1.2T in y direction and fourth piece: -1.2T in x direction and so on... Other properties are sigma=1S/m and epsilon_r=1. Ralf
Muhammad Hamid Khan
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Posted: 1 decade ago Oct 30, 2013, 12:00 a.m. EDT
Thanx a lot Ralf...

I have attached the image below, I assigned remenant flux in accordance to ur instructions.

And let me know last few queries, these might be basic but new for me, so plz let me know that is there something like geometry dependency like I should Flux for circular or curved shape geometries and for straight or rectangular parts, I should use AIR medium and what should be the value of Tesla?
And is cube or cylinder formation is necessary around geometry/magnets to check magnetic field with its medium as air?
And last thing plz that I want to know is that I have fixed the base of a beam and want to check the displacement at a Force with frequency of 50 Hz. Plz mention just brief steps.

Regards and thanx in advance.
Thanx a lot Ralf... I have attached the image below, I assigned remenant flux in accordance to ur instructions. And let me know last few queries, these might be basic but new for me, so plz let me know that is there something like geometry dependency like I should Flux for circular or curved shape geometries and for straight or rectangular parts, I should use AIR medium and what should be the value of Tesla? And is cube or cylinder formation is necessary around geometry/magnets to check magnetic field with its medium as air? And last thing plz that I want to know is that I have fixed the base of a beam and want to check the displacement at a Force with frequency of 50 Hz. Plz mention just brief steps. Regards and thanx in advance.
Ralf Tschiesche
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Posted: 1 decade ago Oct 30, 2013, 2:42 a.m. EDT
Hi!
I think the best would be to study comsol manual and some of the examples in the model gallery:
www.comsol.de/models/acdc-module
There you should find some more explanations for basics.
Ralf
Hi! I think the best would be to study comsol manual and some of the examples in the model gallery: http://www.comsol.de/models/acdc-module There you should find some more explanations for basics. Ralf

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