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Modeling the magnetic field inside a ferromagnetic material .

Posted May 28, 2018, 11:20 a.m. EDT Electromagnetics, Low-Frequency Electromagnetics 5 Replies

Chiro Higue
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Hello

I am working on project in which we need a software that allows us to compute a static magnetic flux density (B) inside a ferromagnetic material, (e.g a permanent magnet placed on a steel block)

I read a little bit the AC/DC Module, however what I could conclude is that the ferromagnetic material is supposed linear (the permeabilty µ is H-independent), I wonder if there has been a new update that allows the computation of such field.

I have also the same question about a dynamic magnetic field (a coil for example) placed on a ferromagnetic material.

5 Replies Last Post May 29, 2018, 9:06 a.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 6 years ago May 28, 2018, 11:30 a.m. EDT

Hi,

a nonlinear approach using a BH curve is no problem. This holds for static and time dependent models.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi, a nonlinear approach using a BH curve is no problem. This holds for static and time dependent models. Cheers Edgar
Chiro Higue
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Posted: 6 years ago May 28, 2018, 11:43 a.m. EDT
Updated: 6 years ago May 28, 2018, 11:43 a.m. EDT

Hello Edgar,

Thank you for the rapid reply,

I do have some B-H curves, however the issue is not getting the H field first, and from the B-H curve the deduction is straight forward.

Maybe I wasn't clear in my previous post (or even misleading ) but the issue in these cases is the H field inside the material, since the tangential component is continuous , however we egnore the normal component.

I was wondering if there is a solution in COMSOL that uses something else other then LLG model.

Hello Edgar, Thank you for the rapid reply, I do have some B-H curves, however the issue is not getting the H field first, and from the B-H curve the deduction is straight forward. Maybe I wasn't clear in my previous post (or even misleading ) but the issue in these cases is the H field inside the material, since the tangential component is continuous , however we egnore the normal component. I was wondering if there is a solution in COMSOL that uses something else other then LLG model.
Edgar J. Kaiser Certified Consultant
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Posted: 6 years ago May 28, 2018, 1:04 p.m. EDT

Sorry, I don't get what the issue is.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Sorry, I don't get what the issue is.
Chiro Higue
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Posted: 6 years ago May 29, 2018, 4:22 a.m. EDT
Updated: 6 years ago May 29, 2018, 4:24 a.m. EDT

Hello Edgar,

It isn't possible to use the B-H curve if one doesn't know the H field inside the material.

The B-H field is a obtained in the case where we know the H field inside the material, and this by making its direction tangential to the surface of the material and its value uniform along the specimen, in the attached picture I try to explain that.

The use of "closed" specimen forms, helps us avoid the discotinuity of the normal component of the H field at the boundaries.

The B-H curve becomes usuful when one knows the H field inside the material.

Once again I thank you for your rapid replys, and I hope COMSOL can provide what we are looking for (The magnetic field density H inside a ferromagnetic material)

Best regards

Hello Edgar, It isn't possible to use the B-H curve if one doesn't know the H field inside the material. The B-H field is a obtained in the case where we know the H field inside the material, and this by making its direction tangential to the surface of the material and its value uniform along the specimen, in the attached picture I try to explain that. *The use of "closed" specimen forms, helps us avoid the discotinuity of the normal component of the H field at the boundaries.* The B-H curve becomes usuful when one knows the H field inside the material. Once again I thank you for your rapid replys, and I hope COMSOL can provide what we are looking for (The magnetic field density H inside a ferromagnetic material) Best regards

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Edgar J. Kaiser Certified Consultant
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Posted: 6 years ago May 29, 2018, 9:06 a.m. EDT

Comsol solves for the magnetic scalar potential Vm or the magnetic vector potential A and the nonlinear material model is respected by the solver. The magnetic field H is made available as the gradient of Vm or the curl of A.

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Comsol solves for the magnetic scalar potential Vm or the magnetic vector potential A and the nonlinear material model is respected by the solver. The magnetic field H is made available as the gradient of Vm or the curl of A.

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