Saturation H-B curve problem

Numerical methods and mathematical models of Elmer
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felipe_andrade
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Joined: 08 Aug 2023, 16:36
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Saturation H-B curve problem

Post by felipe_andrade »

]Hi all,
I`m facing a issue during the simulation. Probably I`m doing something wrong.
My electromagnetic problem is respect of a switch where the objective is calculate the closing magnetic force between the components. The expected result is about 15-17 mN.
When I plot in Paraview the material did not get the saturation.

Code: Select all

! This is a 3D version. To increase accuracy the "Mesh Levels" may be
! increased (1 to 3). Also "quadratic approximation" could be used.
!
! P.R. 30.1.2020

$mu0=4*pi*1.0e-7 ! permeability of vacuum



Header
  CHECK KEYWORDS Warn
  Mesh DB "." "Mesh_Pantry"
  Include Path ""
  Results Directory "Results_Switch"
End

Simulation
  Max Output Level = 5
  Coordinate System = "Cartesian 3D"
  Coordinate Mapping(3) = 1 2 3
  !Coordinate Scaling = 1.0e-3 
  Simulation Type = Steady  State
  Steady State Max Iterations = 10
  Output Intervals(1) = 1
  Timestepping Method = BDF
  BDF Order = 2
  Solver Input File = Reed2.sif
  Post File = case.vtu
End

Constants
  Gravity(4) = 0 -1 0 9.82
  Stefan Boltzmann = 5.67e-08
  Permittivity of Vacuum = 8.8542e-12
  Permeability of Vacuum = 1.25663706e-6
  Boltzmann Constant = 1.3807e-23
  Unit Charge = 1.602e-19
End

Body 1
  Name = String "Magnet"
  Target Bodies(1) = 1
  Equation = 4
  Material = 2
  Body Force = 1
End

Body 2
  Name = String "Reed_1"
  Target Bodies(1) = 2
  Equation = 2
  Material = 3
End

Body 3
  Name = String "Box"
  Target Bodies(1) = 3
  Equation = 3
  Material = 1
End

Body 4
  Name = String "Reed_3"
  Target Bodies(1) = 4
  Equation = 2
  Material = 3
End

Body 5
  Name = String "Reed_4"
  Target Bodies(1) = 5
  Equation = 2
  Material = 3
End

Body 6
  Name = String "Reed_2"
  Target Bodies(1) = 6
  Equation = 2
  Material = 3
End

Equation 1
  Name = "MgDyn for iron"
  Active Solvers(3) = 1 2 3 4
End 

Equation 2
  Name = "MgDyn for switch"
  Active Solvers(3) = 1 2 3 4
End 

Equation 3
  Name = "MgDyn for air"
  Active Solvers(2) = 1 2 3
End 

Equation 4
  Name = "MgDyn for Magnet"
  Active Solvers(2) = 1 2 3
End 

Material 1
  Name = "Air"
  Relative Permeability = Real 1.0
  Relative Permittivity = Real 0.0
End

Material 2
  Name = "N50M"
  Relative Permittivity = Real 1.00
  Relative Permeability = Real 1.08632
End

Material 3
  Name = "Iron"
  H-B curve = Variable coupled iter
    real 
      INCLUDE BH_Iron_New.dat
  End
End

Body Force 1
  Name = "Magnetization"
  Magnetization 1 = Real 0.0
  Magnetization 2 = Real 0.0
  Magnetization 3 = Real -923000
End

Boundary Condition 1
  Name = String "InfinityBC"
  Target Boundaries(1) = 1
  AV re = real 0.0
  AV im = real 0.0
  AV re {e} = real 0.0
  AV im {e} = real 0.0 
  Magnetic Flux Density 1 = Real 0
  Magnetic Flux Density 2 = Real 0 
  Magnetic Flux Density 3 = Real 0
End

Component 1
  Master Bodies(1) = 4
  Calculate Magnetic Force = Logical True
End

Component 2
  Master Bodies(1) = 5
  Calculate Magnetic Force = Logical True
End


Solver 1
  Equation = MgDyn3D
  Procedure = "MagnetoDynamics" "WhitneyAVSolver"
  Exec Solver = After Timestep
  Variable =  String "AV"
  
  Exec Solver = Always
  Optimize Bandwidth = True
  Steady State Convergence Tolerance = 1.0e-5
  Nonlinear System Convergence Tolerance = 1.0e-5
  Nonlinear System Max Iterations = 20
  Nonlinear System Newton After Iterations = 3
  Nonlinear System Newton After Tolerance = 1e-3
  Nonlinear System Relaxation Factor = 1
  Linear System Solver = Iterative
  Linear System Iterative Method = BiCgstabl
  Linear System Max Iterations = 2500
  Linear System Convergence Tolerance = 1.0e-8
  Linear System Robust = Logical True
  BiCGstabl polynomial degree = 2
  Linear System Preconditioning = ILU06
  Linear System ILUT Tolerance = 1.0e-3
  Linear System Abort Not Converged = False
  Linear System Residual Output = 10
  Linear System Precondition Recompute = 1
  
End


Solver 2
  Equation = MgDynPost
  Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
  Exec Solver = Always
  Stabilize = True
  Potential Variable = String "AV"
  Calculate Magnetic Field Strength = True
  Separate Magnetic Field = Logical True
  Use Piola Transform = true
  Steady State Convergence Tolerance = 1.0e-5
  
  Optimize Bandwidth = True
  Calculate Elemental Fields = True Component 1
  
  Nonlinear System Convergence Tolerance = 1.0e-10
  Nonlinear System Max Iterations = 20
  Nonlinear System Newton After Iterations = 3
  Nonlinear System Newton After Tolerance = 1e-3
  Nonlinear System Relaxation Factor = 1
  Linear System Solver = Iterative
  Linear System Iterative Method = BiCgstabl
  Linear System Max Iterations = 2500
  Linear System Convergence Tolerance = 1.0e-8
  BiCGStabl Polynomial Degree = 6
  Linear System Preconditioning = ILU0
  Linear System ILUT Tolerance = 1.0e-6
  Linear System Abort Not Converged = False
  Linear System Residual Output = 10
  Linear System Precondition Recompute = 1
  
  Discontinuous Bodies = Logical True
  
  Calculate Magnetic Force = Logical True
  Calculate Magnetic Field Strength = Logical True
  Calculate Magnetic Flux Density = Logical True
  Calculate Nodal Forces = True
  Calculate Magnetic Vector Potential = Logical True
  
End

Solver 3
  Exec Solver = "after saving"
  Equation = "ResultOutput"
  Procedure = "ResultOutputSolve" "ResultOutputSolver"
  Output File Name = case_res_qd
  Vtu format = Logical True
  Binary Output = Logical True
  Discontinuous Bodies = Logical True
  Save Elemental Fields = Logical True
  Save Geometry Ids = True
  Save Bulk Only = True
End

Solver 4
  Exec Solver = After All
  Equation = SaveScalars
  Procedure = "SaveData" "SaveScalars"
  Filename = "force.dat"
  Save Component Results = logical true
End



! consistency norms
Solver 1 :: Reference Norm = 1.62837615E-08
Solver 3 :: Reference Norm = 1.83305239E-02
Last edited by felipe_andrade on 28 Nov 2023, 16:45, edited 1 time in total.
vencels
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Re: Saturation H-B curve problem

Post by vencels »

Could you share a BH curve or even better an entire case as it is not clear where magnets are?
felipe_andrade
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Re: Saturation H-B curve problem

Post by felipe_andrade »

Hi,
The problem is described bellow, also I`m sharing the BH curve
Attachments
BH_Iron_New.dat
(592 Bytes) Downloaded 44 times
gforti
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Re: Saturation H-B curve problem

Post by gforti »

What material is the one defined by this BH curve?
felipe_andrade
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Re: Saturation H-B curve problem

Post by felipe_andrade »

gforti wrote: 09 Aug 2023, 16:53 What material is the one defined by this BH curve?
The switch is represented by the curve (Bodies 2,4,5,6 - Material 3) and the magnet by Body 1 - Material 2.
gforti
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Re: Saturation H-B curve problem

Post by gforti »

I meant the actual material, is it magnetic steel (silicon steel)?
felipe_andrade
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Re: Saturation H-B curve problem

Post by felipe_andrade »

gforti wrote: 09 Aug 2023, 17:07 I meant the actual material, is it magnetic steel (silicon steel)?
Ah ok my apologies. It`s a specific NiFe magnetic steel.
vencels
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Re: Saturation H-B curve problem

Post by vencels »

Extend your BH curve into the saturation region or at least for higher H values.
It might be that Elmer is linearly extrapolating your curve.
Screenshot_3.png
(49.99 KiB) Not downloaded yet
felipe_andrade
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Re: Saturation H-B curve problem

Post by felipe_andrade »

Excelent Vencels,
It is working, thank you so much for you help
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