Non-linear demagnetization curve input for magnet material
Posted: 04 Jan 2024, 20:08
Hi,
I am trying to use Elmer to calculate demagnetisation behaviour of a magnet, in order to do so I need to input a demagnetisation curve (where its knee point is at B>0 and H are negative values). I changed the PM material section according to this post :https://www.elmerfem.org/forum/viewtopic.php?t=7042
Specifically these few lines:
So my PM material input is
However the Elmer result is not sensible(as shown in the first image below) and it is different from Ansys Maxwell's result (as shownin the second image below)
By changing the PM material code in the .sif file I also find that:
1. Elmer simulation doesn't want to converge when my input of Magnetization is Smaller than the Hc of the BH data (For example Magnetization 2 = 700000 and this Hc = -519435 ).
2. Changing the Relative Permeability value doesn't impact the result. Even if I delete the complete line of Relative Permeability.
3. Both of changing magnitude of BH curve and Magnetization 1 or 2 can vary the simulation result.
So my question is , what is the correct input when I have a non-linear demagnetisation curve for magnet material?
Kind regards,
Eric
I am trying to use Elmer to calculate demagnetisation behaviour of a magnet, in order to do so I need to input a demagnetisation curve (where its knee point is at B>0 and H are negative values). I changed the PM material section according to this post :https://www.elmerfem.org/forum/viewtopic.php?t=7042
Specifically these few lines:
Code: Select all
Material 2
Name = "N52"
Relative Permeability = 1.05
Magnetization 1 = 956180
Electric Conductivity = 0.667
H-B Curve = Variable "nonlin"
include HB_N52
End
End
Code: Select all
Material 4
Name = "PM"
Relative Permeability = 1.05
Electric Conductivity = 0
Magnetization 1 = 0
Magnetization 2 =519435
H-B Curve = Variable "nonlin"
Real Monotone Cubic
0.000843 -519435
0.056154 -516384
0.092699 -515317
0.131122 -512802
0.169682 -511050
0.201866 -508916
0.233615 -506782
0.26288 -504542
0.293817 -501448
0.33042 -498247
0.362566 -493980
0.392992 -489179
0.421125 -483312
0.450756 -475310
0.478149 -465175
0.5016 -453973
0.521266 -442238
0.538269 -430503
0.554577 -418767
0.571002 -407032
0.58731 -395297
0.60304 -383561
0.618886 -371826
0.633342 -360091
0.649535 -348355
0.665265 -336620
0.680763 -324885
0.694873 -313149
0.710834 -301414
0.727258 -289679
0.742525 -277943
0.757445 -266208
0.773753 -254473
0.78902 -242737
0.804287 -231002
0.818744 -219267
0.834705 -207531
0.84974 -195796
0.865818 -184061
0.881663 -172326
0.89774 -160590
0.912313 -148855
0.928968 -137120
0.944814 -125384
0.960312 -113649
0.974653 -101914
0.989689 -90178.3
1.00484 -78442.9
1.021727 -66707.6
1.035605 -54972.3
1.051219 -43237
1.066717 -31501.6
1.081405 -19766.3
1.097019 -8030.99
1.108842 -557.999
End
End
By changing the PM material code in the .sif file I also find that:
1. Elmer simulation doesn't want to converge when my input of Magnetization is Smaller than the Hc of the BH data (For example Magnetization 2 = 700000 and this Hc = -519435 ).
2. Changing the Relative Permeability value doesn't impact the result. Even if I delete the complete line of Relative Permeability.
3. Both of changing magnitude of BH curve and Magnetization 1 or 2 can vary the simulation result.
So my question is , what is the correct input when I have a non-linear demagnetisation curve for magnet material?
Kind regards,
Eric