Hi all,
I was wondering if anyone with some experience with Zirka materials can let me know if this is a bug or I am missing something. This is a simple case of a coil and a piece of metal (Low frequency, no eddy currents, metal conductivity =0). Case with single BH curve works as expected, but when I switch to a Zirka material things get weird. Other than the overall BH curve not following the input curve, the evolution of the BH curve also seems weird. I used values from the elmer tests. I could trace some of the input parameters to the Zirka paper but others were not that easy to find. For instance, I am not sure why we need to specify a relative permeability (it crashes if it is not included)
Zirka hysteresis model
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Re: Zirka hysteresis model
The answer changes with
element="p:2"
which means mesh quality, density, and order matters.
element="p:2"
which means mesh quality, density, and order matters.
Re: Zirka hysteresis model
Hi Kevin,
Thanks for the suggestion. I added the line to the sif file and results did change, but just a little bit. The outstanding issues remain. In my opinion, there are two:
1. The evolution of the BH curve is not correct 2. Shape is not close to input.
I am not sure why 1 is happening. For 2, the problem seems to come from CalcFields (if relative permeability is not defined in the material, as it is derived from the BH curve). MagnetDynamics2D runs well without a relative permeability input.
I wonder if this is the reason (CalcField.F90, line 1790):
Cheers,
Thanks for the suggestion. I added the line to the sif file and results did change, but just a little bit. The outstanding issues remain. In my opinion, there are two:
1. The evolution of the BH curve is not correct 2. Shape is not close to input.
I am not sure why 1 is happening. For 2, the problem seems to come from CalcFields (if relative permeability is not defined in the material, as it is derived from the BH curve). MagnetDynamics2D runs well without a relative permeability input.
Code: Select all
MagnetoDynamicsCalcFields: ------------------------------
MagnetoDynamicsCalcFields: Computing postprocessed fields
MagnetoDynamicsCalcFields: Using potential variable: az
MagnetoDynamicsCalcFields: Number of components to compute: 13
InitializeToZero: Initializing the linear system to zero
ERROR:: GetReluctivityC: Give > Relative Permeability < or > Reluctivity < for material!
STOP 1
Code: Select all
IF ( (ASSOCIATED(MFS) .OR. ASSOCIATED(EL_MFS)) ) THEN
! Don't really know how to compute MFS with Zirka
! Skipping it will certainly cause errors since k becomes invalid
!IF(.NOT. HasZirka) then
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- Posts: 2362
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Re: Zirka hysteresis model
Just adding element="p:2" doesn't mean the mesh is converged. Depending on how you created the sif means that elmer could output an solution that is not a converged solution. Check especially if the non-linear iterations are actually converging.
Re: Zirka hysteresis model
Hi Kevin,
Thanks again for helping. Nonlinear iterations are converging, even without the relative permeability input as expected
if the BH curve is provided.
Cheers,
Thanks again for helping. Nonlinear iterations are converging, even without the relative permeability input as expected
if the BH curve is provided.
Cheers,