Re: [femm] GO Material

[David Meeker <dmeeker@xxxxxxxxxxxxxxxxx>]

fnent@xxxxxxx wrote:

> I tried assigning the x-y permeabilities but
> the answer was not affected as much as it should have been as your answer
> suggests.

One trick is that anisotropic permeabilities only work if you have not checked
the "Nonlinear B-H Curve" checkbox in the material properties dialog. Failing
that, the program ought to give you something reasonable. It may that in the
geometry that you were considering, the anisotropic permeability just didn't make
that much of a difference. This can happen especially with magnetic circuits
with air gaps. In this case, the reluctance of the air is so high relative to
any iron parts that the geometry of the air gaps almost entirely dictate the flux
distribution. It doesn't make much of a difference whether or not the iron in
the circuit is anisotropic, as long as it still has a relative permeability a lot
higher than 1 in all directions. However, if you make a magnetic circuit in which
the flux passes only through the anisotropic material (and there is a substantial
anisotropy), you will see an obvious qualitative difference in the results.

Dave.


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