B(H) curve of a material: about
Introduction
The user has the possibility to visualize the magnetic properties (curve B(H)) of a material corresponding to the defined model.
This is translated in Flux by a new type of entity named: 2D curve (Material)
If the user wishes to visualize a B(H) curve he must create this curve by using the command New 2D curve (Material) B(H).
This command is available before or after solving. It is necessary that the application be defined to activate the command.
Command access
The command New 2D curve (Material) B(H) is accessible by various ways*:
- from the menu Curve by pointing on 2D curve (Material)
- from the menu Physics by pointing on Material
* It is also possible to access the command New 2D curve (Material) B(H) by the contextual menus starting from the data tree by the node Material in Physics or by the node 2D curve (Material) in Post processing
2D curve (Material): structure
The structure of a 2D curve (Material) is standard; it is independent of the material model. It is defined by:
- Minimum value for H (A/m) and Maximum value for H (A/m): these parameters define the displayed interval of the curve B(H), in A/m.
- Temperature (°C): list of temperature values for which the user wishes to visualize the B(H) curves (only for the models with material properties depending on the temperature).
- Equivalent uniaxial stress (MPa): list of mechanical stress values for which the user wishes to visualize the B(H) curves (only for materials containing a magneto-mechanical property B(Stress) and described by the B(H) magnetic property of type Isotropic analytic saturation + knee adjustment (arctg, 3 coef.).
The field «Temperature (°C)»
The table below describes the operation modes of the field Temperature (°C):
| Material property depending on T | The field is active |
Empty field
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Field containing temperature values The B(H) curves corresponding to the temperature values provided by the user are displayed. |
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| Material property independent of T | The field is inactive | This field is disregarded. |
The field «Equivalent uniaxial stress (MPa)»
The table below describes the operation modes of the field Equivalent uniaxial stress (MPa):
| Material containing a magneto-mechanical property B(Stress) and a B(H) magnetic property of type Isotropic analytic saturation + knee adjustment (arctg, 3 coef.) | The field is active |
Empty field
|
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Field containing mechanical stress values The B(H) curves corresponding to the mechanical stress values provided by the user are displayed. |
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| Material without a magneto-mechanical property B(Stress) or not containing a B(H) magnetic property of type Isotropic analytic saturation + knee adjustment (arctg, 3 coef.) | The field is inactive | This field is disregarded |
Displaying the equivalent B(H) curve of a material in a Steady State AC application
In Steady State AC applications, and in the case of materials of with a B(H) property of types:
- Isotropic analytic saturation,
- Isotropic analytic saturation + knee adjustment and
- Isotropic spline saturation,
the user may ask Flux to use an equivalent B(H) curve determined from the original B(H) curve while creating his material. The use of an equivalent B(H) curve ensures an energy equivalence between the magneto harmonic computation results (which are obtained based on an implicit linearity hypothesis between the magnetic flux density B and the magnetic field intensity H) and the real non-linear behavior of the material, as discussed in the user guide chapter Models approximation in Steady state AC Magnetic applications.
Under such circumstances, if the user decides to use and equivalent B(H) curve while describing a material (i.e., by selecting an option other than Curve not modified in the Type of equivalent B(H) curve drop down menu), displaying the material curve with the New 2D curve (Material) B(H) command will not only display the original B(H) curve described by the user, but will also display the equivalent curve determined by Flux.