Magnets snapping
Two magnets covered by a layer of insulator material (stiff plastic) are coming into contact with each other (snapping) due to electromagnetic forces. This example shows how magnets can be simulated using the EM solver and how dynamic motion due to magnetic forces can be simulated. It uses the FEM-BEM monolithic magnetostatics solver (used for zero-conductivity ferromagnetic materials) and a AMS preconditionner.
https://www.dynaexamples.com/em/eddycurr/magnetsnap
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Magnets snapping
Two magnets covered by a layer of insulator material (stiff plastic) are coming into contact with each other (snapping) due to electromagnetic forces. This example shows how magnets can be simulated using the EM solver and how dynamic motion due to magnetic forces can be simulated. It uses the FEM-BEM monolithic magnetostatics solver (used for zero-conductivity ferromagnetic materials) and a AMS preconditionner.
Two magnets covered by a layer of insulator material (stiff plastic) are coming into contact with each other (snapping) due to electromagnetic forces. This example shows how magnets can be simulated using the EM solver and how dynamic motion due to magnetic forces can be simulated. It uses the FEM-BEM monolithic magnetostatics solver (used for zero-conductivity ferromagnetic materials) and a AMS preconditionner.
*CONTROL_TERMINATION *CONTROL_TIMESTEP *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *EM_CIRCUIT *EM_CONTROL
*EM_CONTROL_COUPLING *EM_CONTROL_TIMESTEP *EM_MAT_001
*EM_MAT_002
*EM_OUTPUT
*EM_PERMANENT_MAGNET
*EM_SOLVER_BEM
*EM_SOLVER_BEMMAT
*EM_SOLVER_FEM
*EM_SOLVER_FEMBEM_MONOLITHIC *END *KEYWORD *MAT_RIGID *PARAMETER *PART *SECTION_SOLID *TITLE
*keyword
$ ****************************************************************************
$ electromagnetism
$ ****************************************************************************
*EM_CONTROL
$--------1---------2---------3---------4---------5---------6---------7---------8
$ emsol numls dt
1 &emdt &em_femmtx&em_bemmtx
*EM_CONTROL_COUPLING
,2
*EM_SOLVER_FEM
$--------1---------2---------3---------4---------5---------6---------7---------8
$ reltol maxiter stype precon uselast ncyclfem msglvlFem
1.e-4 10000 1 1 1 0
*EM_SOLVER_BEM
$--------1---------2---------3---------4---------5---------6---------7---------8
$ reltol maxiter solvetype precon uselast ncyclbem
&btol 10000 2 2 1
$*EM_SOLVER_FEMBEM
$$--------1---------2---------3---------4---------5---------6---------7---------8
$$ reltol maxiter forcon
$ 1.e-6 50 3
*EM_SOLVER_BEMMAT
$--------1---------2---------3---------4---------5---------6---------7---------8
$ matId relTol
1 &ptol
*EM_SOLVER_BEMMAT
$--------1---------2---------3---------4---------5---------6---------7---------8
$ matId relTol
2 &qtol
*EM_SOLVER_BEMMAT
$--------1---------2---------3---------4---------5---------6---------7---------8
$ matId relTol
3 &wtol
*EM_PERMANENT_MAGNET
$--------1---------2---------3---------4---------5---------6---------7---------8
$ ID Part ID - North South M=0.38/mu0
1 1 1 2 9.e5
*DEFINE_CURVE
100,
0,9.e5
5e-3,9.e5
1.,9.e5
*EM_PERMANENT_MAGNET
$--------1---------2---------3---------4---------5---------6---------7---------8
$ ID Part ID - North South M=0.38/mu0
3 3 3 4 9.e5
*EM_MAT_002
$ Magnetic material 1
$ mid mtype sigma eosid murel eosmu
1 4 0. 0 &murel1
$ 1 4 &sigma1 0 &murel1
*EM_MAT_002
$ Magnetic material 2
$--------1---------2---------3---------4---------5---------6---------7---------8
$ mid mtype sigma eosid murel eosmu
3 4 0. 0 &murel3
$ 3 4 &sigma3 0 &murel3
*EM_MAT_001
$ Dummy coil material
$--------1---------2---------3---------4---------5---------6---------7---------8
$ mid mtype sigma eosid
2 1
*EM_MAT_001
$ Dummy coil material
$--------1---------2---------3---------4---------5---------6---------7---------8
$ mid mtype sigma eosid
4 1
*EM_OUTPUT
$--------1---------2---------3---------4---------5---------6---------7---------8
$ matS matF solS solF mesh memory timing d3plotAsc
2 2 2 2 0 0 0
$ mf2 gmv d3plotFor timeHist
0 1 0
*EM_SOLVER_FEMBEM_MONOLITHIC
$--------1---------2---------3---------4---------5---------6---------7---------8
$ COUPLING KSP_TYPE KSP_ATOL KSP_RTOL KSP_MAXIT GMRES_RST FEM_PC DEBUG
0 1.e-9 1.e-5 100000 1
$--------1---------2---------3---------4---------5---------6---------7---------8
$ FORCE NEWT_STOL NEWT_ATOL NEWT_RTOL NEWT_MAXI
1.e-9 1.e-9 1.e-5
$--------1---------2---------3---------4---------5---------6---------7---------8
$ LS_ON LS_FTOL LS_GTOL LS_RTOL LS_SAMPL LS_NUM_SP LS_MAXFUN
1 1.e-9 0.01 1.e-5 30000
$--------1---------2---------3---------4---------5---------6---------7---------8
$$USE_ENERG STOP_ERR WIDTH_ERR XTRAPF
$
*EM_EOS_PERMEABILITY
$ eostype=1 --> B = B(H), eostype=2 --> H = H(B)
$--------1---------2---------3---------4---------5---------6---------7---------8
$ eosid eostype lcid
101 2 102
*DEFINE_CURVE
$ Dummy current
$ LCID SIDR SFA SFO OFFA OFFO DATTYP
$--------1---------2---------3---------4---------5---------6---------7
999 0.0
0.000,0.00
9.000,0.00
$
*define_curve
$B=B(H)
101
0.0,0.00000
1757.0,0.01287
3515.0,0.14758
4173.0,0.15738
5894.0,0.16830
8640.0,0.18008
12348.0,0.19246
16935.0,0.20516
22297.0,0.21789
28313.0,0.23036
34847.0,0.24230
41751.0,0.25343
48870.0,0.26350
138035.0,0.38115
227200.0,0.49880
316364.0,0.61645
405529.0,0.73410
494694.0,0.85175
583859.0,0.96940
673024.0,1.08705
762188.0,1.20470
851353.2,1.32235
940518.0,1.43999
$
*define_curve
$ H=H(B)
102
0.0,0.00000
0.01287,1757.0
0.14758,3515.0
0.15738,4173.0
0.16830,5894.0
0.18008,8640.0
0.19246,12348.0
0.20516,16935.0
0.21789,22297.0
0.23036,28313.0
0.24230,34847.0
0.25343,41751.0
0.26350,48870.0
0.38115,138035.0
0.49880,227200.0
0.61645,316364.0
0.73410,405529.0
0.85175,494694.0
0.96940,583859.0
1.08705,673024.0
1.20470,762188.0
1.32235,851353.2
1.43999,940518.0
$
*DEFINE_CURVE
333
0.,1.
0.04,1.
0.04001,-1.
1.,-1.
*end
