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Convergence problem while simulating a degaussing process

Posted 2015年2月27日 GMT-5 09:31 Low-Frequency Electromagnetics, Studies & Solvers Version 4.3 2 Replies

Rook Jameson
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Hello,
I'm currently running 3-D simulations of ferromagnetic materials that are being degaussed. When I use the "Magnetic Fields" node it works quite well, however, then everything depends on the magnetic flux B, which physically doesn't really make sense.
So I would rather have everything depend on the magnetic field H, which is why I am trying to run my simulations using the "Magnetic Field Formulation" node. Unfortionately, so far it hasn't worked. The problem is, I always get the error message:

Nonlinear solver did not converge.
Maximum number of Newton iterations reached.
There was an error message from the linear solver.
The relative error (4e+02) is greater than the relative tolerance.
Time : 4.358435242653585e-07
Last time step is not converged.

I have attached the model. Any Ideas what the problem might be?

Thanks in advance,
Rook



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2 Replies Last Post 2015年9月9日 GMT-4 04:13
COMSOL Moderator

Hello Rook Jameson

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Aden
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Posted: 9 years ago 2015年9月8日 GMT-4 04:42
Hey Rook

Have you found the reason behind that error??

Regards
Hey Rook Have you found the reason behind that error?? Regards
Rook Jameson
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Posted: 9 years ago 2015年9月9日 GMT-4 04:13
Kinda. I guess the reason that it doesn’t work is a flaw in my logic. I was thinking, H is given by the external coils, so I should have a function dependent of H. But what you give Comsol is actually a differential equation, not a function. So now Comsol tries to solve the equation for H, even though H is already given. This causes the problem I guess.
When I use the magnetic field node and let my differential equation solve for B, then it works pretty well.

Regards
Kinda. I guess the reason that it doesn’t work is a flaw in my logic. I was thinking, H is given by the external coils, so I should have a function dependent of H. But what you give Comsol is actually a differential equation, not a function. So now Comsol tries to solve the equation for H, even though H is already given. This causes the problem I guess. When I use the magnetic field node and let my differential equation solve for B, then it works pretty well. Regards

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