Products: Abaqus/Standard Abaqus/CAE
A material's magnetic permeability:
must be defined for “Eddy current analysis,” Section 6.7.5, and “Magnetostatic analysis,” Section 6.7.6;
can be specified directly for linear magnetic behavior or through one or more B–H curves for nonlinear magnetic behavior;
can be isotropic, orthotropic, or (in the case of linear behavior) fully anisotropic;
can be specified as a function of temperature and/or field variables; and
can be specified as a function of frequency in a time-harmonic eddy current procedure.
Linear magnetic behavior is defined by direct specification of magnetic permeability.
Isotropic, orthotropic, or fully anisotropic magnetic permeability can be defined. For non-isotropic magnetic permeability a local orientation for the material directions must be specified (“Orientations,” Section 2.2.5).
For isotropic magnetic permeability only one value of magnetic permeability is needed at each temperature and field variable value. Isotropic magnetic permeability is the default.
| Input File Usage: | *MAGNETIC PERMEABILITY, TYPE=ISOTROPIC |
| Abaqus/CAE Usage: | Property module: material editor: Electrical/Magnetic |
For orthotropic magnetic permeability three values of magnetic permeability (
, 
, 
) are needed at each temperature and field variable value.
| Input File Usage: | *MAGNETIC PERMEABILITY, TYPE=ORTHOTROPIC |
| Abaqus/CAE Usage: | Property module: material editor: Electrical/Magnetic |
For fully anisotropic magnetic permeability six values (, 
, 
, 
, 
, ) are needed at each temperature and field variable value.
| Input File Usage: | *MAGNETIC PERMEABILITY, TYPE=ANISOTROPIC |
| Abaqus/CAE Usage: | Property module: material editor: Electrical/Magnetic |
Magnetic permeability can be defined as a function of frequency in a time-harmonic eddy current analysis.
| Input File Usage: | *MAGNETIC PERMEABILITY, FREQUENCY |
| Abaqus/CAE Usage: | Property module: material editor: Electrical/Magnetic |
Nonlinear magnetic behavior is characterized by magnetic permeability that depends on the strength of the magnetic field. The nonlinear magnetic material model in Abaqus is suitable for ideally soft magnetic materials (without any hysteresis effects) characterized by a monotonically increasing response in B–H space, where B and H refer to the strengths of the magnetic flux density vector and the magnetic field vector, respectively. Nonlinear magnetic behavior is defined through direct specification of one or more B–H curves that provide B as a function of H and, optionally, temperature and/or predefined field variables, in one or more directions. Nonlinear magnetic behavior can be isotropic, orthotropic, or transversely isotropic (which is a special case of the more general orthotropic behavior). More than one B–H curve is needed to define the nonlinear magnetic behavior if it is not isotropic.
Isotropic, orthotropic, or transversely isotropic nonlinear magnetic behavior can be defined. For non-isotropic nonlinear magnetic behavior a local orientation for the material directions must be specified (“Orientations,” Section 2.2.5).
For isotropic nonlinear magnetic response only one B–H curve is needed at each temperature and field variable value. Isotropic magnetic permeability is the default. Abaqus assumes that the nonlinear magnetic behavior is governed by
| Input File Usage: | You define  through a B–H curve: |
*MAGNETIC PERMEABILITY, NONLINEAR, TYPE=ISOTROPIC *NONLINEAR BH, DIR=direction The B–H curve in any direction (i.e., the nonlinear behavior in global direction 1, 2, or 3) will suffice as the nonlinear magnetic behavior is assumed to be the same in all directions. |
| Abaqus/CAE Usage: | Nonlinear magnetic behavior is not supported in Abaqus/CAE. |
For orthotropic nonlinear magnetic response three B–H curves (one curve to define the behavior in each of the local directions 1, 2, and 3) are needed at each temperature and field variable value. Abaqus assumes that the nonlinear magnetic behavior in the local material directions is governed by
refers to a diagonal matrix.Transversely isotropic nonlinear magnetic behavior is a special case of orthotropic behavior, in which the behavior in any two directions is the same and is different from that in the third direction.
| Input File Usage: | You define  ,  , and  , respectively, through three independent B–H curves, one in each of the directions 1, 2, and 3: |
*MAGNETIC PERMEABILITY, NONLINEAR, TYPE=ORTHOTROPIC *NONLINEAR BH, DIR=1 … *NONLINEAR BH, DIR=2 … *NONLINEAR BH, DIR=3 … |
| Abaqus/CAE Usage: | Nonlinear magnetic behavior is not supported in Abaqus/CAE. |
Magnetic material behavior is active only in electromagnetic elements (see “Choosing the appropriate element for an analysis type,” Section 27.1.3).
