[Getdp] Permanent magnet in GetDP
Jasper
funkybob at gmail.com
Wed Aug 9 16:37:12 CEST 2017
Hi Gilles,
Your suggestion is typically the way I've done it in the past, specify by
HcB and mu_r. From my understanding, in a NdFeB magnet at low temperatures
this linear relation should be valid and the results have appear plausible
so far :-)
Keep in mind that once the relatively small difference between e.g. N40 and
N42 starts to matter in your simulation you should really consult your
magnet supplier as the magnets typically have tolerances and are also not
completely homogenous etc...
Best regards,
Jasper
On Wed, Aug 9, 2017 at 11:55 AM, gilles quemener <quemener at lpccaen.in2p3.fr>
wrote:
> 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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