[Getdp] Permanent magnet in GetDP
gilles quemener
quemener at lpccaen.in2p3.fr
Wed Aug 9 11:55:06 CEST 2017
Hi,
Following my previous message, I digged more into the .pro files of GetDP demos magnet.xxx
and it seems that one could perhaps use both Hc and µ_r to distinguish between NdFeB magnets grades.
In GetDP demos, the permanent magnets material could be defined as in MaterialDatabase.pro w/
the following lines :
// NdFeB magnet N45
Materials() += Str[ "NdFeB_Grade_N45" ];
NdFeB_mur = 1.172; // Br = 1370 mT, Hcb = 930000 A/m and µ_r = Br / Hcb / µ_o
NdFeB_sigma = 2e5;
NdFeB_hc = 930000;
where µ_r and Hcb values have been taken from the ttypical table below.
Could anyone confirm or infirm this approach ?
Remanence
coercivity
coercivity
product
Br
Hcb
Hcj
B H max
µ = Br / Hcb µ_r= µ / µo
mT
kA/m
kA/m
kJ/m3
T/A/m
min typ min typ min min typ °C
N-35 1170 1120 870 920 955 263 279 80 1.217391E-06 0.969
N-38 1220 1260 870 920 955 279 303 80 1.369565E-06 1.090
N-40 1260 1300 870 920 955 303 318 80 1.413043E-06 1.124
N-42 1300 1330 870 920 955 318 334 80 1.445652E-06 1.150
N-45 1330 1370 900 930 955 334 358 80 1.473118E-06 1.172
N-48 1370 1410 900 930 875 358 382 80 1.516129E-06 1.206
N-50 1410 1440 830 850 875 382 398 80 1.694118E-06 1.348
N-52 1430 1480 820 840 875 398 422 80 1.761905E-06 1.402
N-33M 1140 1170 830 859 1114 239 263 100 1.362049E-06 1.084
N-35M 1170 1220 870 891 1114 263 279 100 1.369248E-06 1.090
N-38M 1220 1260 900 915 1114 279 303 100 1.377049E-06 1.096
N-40M 1260 1300 930 915 1114 303 318 100 1.420765E-06 1.131
N-42M 1300 1330 950 915 1114 318 334 100 1.453552E-06 1.157
N-45M 1330 1370 980 915 1114 334 358 100 1.497268E-06 1.191
N-48M 1370 1410 1010 980 1114 358 382 90 1.438776E-06 1.145
N-50M 1410 1440 1030 980 1114 382 398 90 1.469388E-06 1.169
N-30H 1080 1140 810 810 1353 223 239 120 1.407407E-06 1.120
N-33H 1140 1170 830 830 1353 239 263 120 1.409639E-06 1.122
N-35H 1170 1220 870 870 1353 263 279 120 1.402299E-06 1.116
N-38H 1220 1260 900 900 1353 279 303 120 1.400000E-06 1.114
N-40H 1260 1300 930 930 1353 303 318 120 1.397849E-06 1.112
N-42H 1300 1330 950 950 1353 318 334 120 1.400000E-06 1.114
N-44H 1330 1360 970 970 1353 334 350 120 1.402062E-06 1.116
N-46H 1360 1380 980 980 1353 350 366 120 1.408163E-06 1.121
N-48H 1380 1410 1010 1060 1353 366 382 120 1.330189E-06 1.059
N-30SH 1080 1140 810 860 1592 223 239 150 1.325581E-06 1.055
N-33SH 1140 1170 830 880 1592 239 263 150 1.329545E-06 1.058
N-35SH 1170 1220 870 920 1592 263 279 150 1.326087E-06 1.055
N-38SH 1220 1260 900 950 1592 279 303 150 1.326316E-06 1.055
N-40SH 1260 1300 930 980 1592 303 318 150 1.326531E-06 1.056
N-42SH 1300 1330 950 1000 1592 318 334 150 1.330000E-06 1.058
N-44SH 1330 1360 970 1020 1592 334 350 150 1.333333E-06 1.061
N-28UH 1040 1080 770 810 1989 199 223 180 1.333333E-06 1.061
N-30UH 1080 1140 810 860 1989 223 239 180 1.325581E-06 1.055
N-33UH 1140 1170 830 880 1989 239 263 180 1.329545E-06 1.058
N-35UH 1170 1220 870 920 1989 263 279 180 1.326087E-06 1.055
N-38UH 1220 1260 900 950 1989 279 303 180 1.326316E-06 1.055
N-40UH 1250 1280 900 950 1989 302 326 180 1.347368E-06 1.072
N-28EH 1040 1080 770 810 2387 199 223 200 1.333333E-06 1.061
N-30EH 1080 1140 810 860 2387 223 239 200 1.325581E-06 1.055
N-33EH 1140 1170 830 880 2387 239 263 200 1.329545E-06 1.058
N-35EH 1170 1220 870 920 2387 263 279 200 1.326087E-06 1.055
N-38EH 1220 1260 900 950 2387 279 303 200 1.326316E-06 1.055
N-25AH 970 1020 730 770 2787 180 200 220 1.324675E-06 1.054
N-28AH 1040 1080 770 810 2787 203 218 220 1.333333E-06 1.061
N-30AH 1080 1140 810 860 2787 220 250 220 1.325581E-06 1.055
N-25BH 950 1000 710 750 3000 170 190 230 1.333333E-06 1.061
Data upto temperature column from :
http://www.goudsmitmagnets.com/magnets-assemblies/permanent-magnets/neodymium-magnets-ndfeb/neodymium-magnets-ndfeb
Cheers,
Gilles
> De: "Gilles Quéméner" <quemener at lpccaen.in2p3.fr>
> À: "getdp" <getdp at onelab.info>
> Envoyé: Mercredi 9 Août 2017 10:21:31
> Objet: Permanent magnet in GetDP
> Hi,
> When simulating permanent NdFeB magnets in a homemade BEM program, I use a
> permeability of 1.05 and a remanent magnetization/field
> depending on the magnet grade as given for instance in the following table :
> Minimum Values
> Grade Br Hc (Hcb) Hci (Hcj) BHmax
> (T) (kA/m) (kA/m) (kJ/m³)
> N27 1.030 796 955 199
> N30 1.080 796 955 223
> N33 1.130 836 955 247
> N35 1.170 867 955 263
> N38 1.210 899 955 287
> N40 1.240 923 955 302
> N42 1.280 923 955 318
> N45 1.320 875 955 342
> N48 1.380 836 875 366
> N50 1.400 796 875 382
> N52 1.430 796 875 398
> Looking closer to the magnet.xxx files in the GetDP demos folder, I cannot
> figure out how the
> remanent magnetization is taken into account as only Hc seems to be used in the
> material definition.
> I would think that both Hc and Br should be used.
> How would one distinguish between N40 and N42 grades which have the same Hc
> values ? How the fact
> that an N50 magnet has a larger remanent field than an N40 one is accounted for
> in GetDP when
> Hc(N50) is smaller than Hc(N40) and equal to Hc(N27) ?
> Thanks a lot for any hints,
> Gilles
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