Defining Electromagnetic Material Properties

In electromagnetic applications, you define the magnetic permeability $μ$ , which defines the relationship between the magnetic flux density $B$ and the magnetic field $H$ . In transient simulations, you also define the electrical conductivity $σ$ , which defines the relationship between the electric current density $J$ and the electric field $E$ according to Ohm's law.

For more information, see Eqn. (4220) and Eqn. (4234).

The following steps describe the general workflow for setting electromagnetic material properties. For details on the specific methods that are available for different magnetic vector potential models, see:

For instructions on defining material properties as a function of temperature, see Defining Temperature-Dependent Properties.

To define the magnetic permeability of a material:

Expand the relevant [physics continuum] > Models > [Material Model] > [Material] > Material Properties node.

Select the Magnetic Permeability node and set its Method based on the type of material that you want to model:


Material	Steps
Fluid	Set Method to either Constant or Field Function. Specify an appropriate value or field function under the Magnetic Permeability node.
Isotropic solid	For diamagnetic and paramagnetic solids, where the relationship between $B$ and $H$ is approximately linear, set Method to either Constant or Field Function, then specify an appropriate value or field function under the Magnetic Permeability node. For ferromagnetic solids, where the magnetization is a nonlinear process, set Method to Table(B,H). This method allows you to specify a nonlinear $B$ - $H$ curve using a table of $B, H$ values. For further instructions, see Defining the Magnetic Permeability Using a B-H Curve.
Non-isotropic solid (only available for the Finite Element Magnetic Vector Potential model)	Set Method to one of the following: For diamagnetic and paramagnetic solids, select one of the general methods for tensor profiles (Anisotropic, Orthotropic, or Transverse Isotropic). For more information, see Tensor Quantities. For ferromagnetic solids, select Table(B,H) Anisotropic. This method allows you to specify up to three different $B$ - $H$ curves (one for each axis of a specified coordinate system) using tables of $B, H$ values. Expand the Magnetic Permeability node and define the tensor components. When using the Table(B,H) Anisotropic method, you can define linear components using the Constant method and nonlinear components using the Table(B,H) method (see Defining the Magnetic Permeability Using a B-H Curve). For each anisotropic region, select the [Region] > Physics Values > Permeability Orientation node and select the local orientation with respect to which the tensor components are defined (see Orientation Manager and Local Orientations).

To define the electrical conductivity of a material:

Select the Material Properties > Electrical Conductivity node and choose the Method for defining $σ$ .

The available methods depend on the selected magnetic vector potential model. General guidelines and instructions are provided for the Electrodynamic Potential model (see Defining the Electrical Conductivity).
Specify the value of $σ$ as required by the selected method.