• Magnetic field simulation supports 4 categories of material properties:

  1. Linear "soft" magnetic materials - typically used in low saturation cases. A Relative Permeability is required. This may be constant, or orthotropic with respect to the coordinate system of the body (See Details view). Orthotropic properties are often used to simulate laminate materials.

  2. Linear "hard" magnetic materials - used to model permanent magnets. The demagnetization curve of the magnet is assumed to be linear. Residual Induction and Coercive Force are required.

  3. Nonlinear "soft" magnetic material - used to model devices which undergo magnetic saturation. A B-H curve is required. For orthotropic materials, you can assign the B-H curve in any of the orthotropic directions, while specifying a constant Relative Permeability in the other directions. (Specifying a value of "0" for Relative Permeability will make use of the B-H curve in that direction.)

  4. Nonlinear "hard" magnetic material - used to model nonlinear permanent magnets. A B-H curve modeling the material demagnetization curve is required.

• When using an Ansys license that includes the Emag license feature, only the following material properties are allowed: Isotropic Resistivity, Orthotropic Resistivity, Relative Permeability, Relative Permeability (Orthotropic), Coercive Force & Residual Induction, B-H Curve, B-H Curve (Orthotropic), Demagnetization B-H Curve. You may have to turn the filter off in the Engineering Data tab to suppress or delete those material properties/models that are not supported for the license.

• Conductor bodies require a Resistivity material property. Solid source conductor bodies can be constant or orthotropic with respect to the coordinate system of the body. Stranded source conductor bodies can only be modeled as isotropic materials.

• For convenience, a library of common B-H curves for soft magnetic material is supplied with the product. Use the Import tool in Engineering Data to review and retrieve curves for use.

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Note:  In a magnetostatic analysis, you can orient a polarization axis for a Linear or Nonlinear Hard material in either the positive or negative x direction with respect to a local or global coordinate system. Use the Material Polarization setting in the Details view for each body to establish this direction. The Material Polarization setting appears only if a hard material property is defined for the body. For a cylindrical coordinate system, a positive x polarization is in the positive radial direction, and a negative x polarization is in the negative radial direction.

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There are no specific considerations for a magnetostatic analysis.

Mechanical does not support Rigid Bodies in Magnetostatic analyses. For more information, see the Stiffness Behavior documentation for Rigid Bodies.

Connections are not supported in a magnetostatic analysis.

• Although your body is automatically meshed at solve time, it is recommended that you select the Electromagnetic Physics Preference in the Details view of the Mesh object folder.

• Solution accuracy is dependent on mesh density. Accurate force or torque calculations require a fine mesh in the air regions surrounding the bodies of interest.

• The use of pyramid elements in critical regions should be minimized. Pyramid elements are used to transition from hexagonal to tetrahedral elements. You can eliminate pyramid elements from the model by specifying Tetrahedrons using a Method mesh control tool.

For a Magnetostatic Analysis, the basic Analysis Settings include:

Step Controls for Static and Transient Analyses

Step Controls are used to specify the end time of a step in a single or multiple step analysis.

Multiple steps are needed if you want to change load values, the solution settings, or the solution output frequency over specific steps. Typically you do not need to change the default values.

Solver Controls

Solver Controls enable you to select either a direct or iterative solver. By default the program will use the direct solver. Convergence is guaranteed with the direct solver. Use the Iterative solver only in cases where machine memory is an issue. The solution is not guaranteed to converge for the iterative solver.

Nonlinear Controls

Nonlinear Controls enable you to modify convergence criteria and other specialized solution controls. These controls are used when your solution is nonlinear such as with the use of nonlinear material properties (B-H curve). Typically you will not need to change the default values for this control. CSG convergence is the criteria used to converge the magnetic field. CSG represents magnetic flux. AMPS convergence is only used for temperature-dependent electric current conduction for solid conductor bodies. AMPS represents current.

Output Controls

Output Controls enable you to specify the time points at which results should be available for postprocessing. A multi-step analysis involves calculating solutions at several time points in the load history. However you may not be interested in all of the possible results items and writing all the results can make the result file size unwieldy. You can restrict the amount of output by requesting results only at certain time points or limit the results that go onto the results file at each time point.

Analysis Data Management

The Analysis Data Management settings enable you to save solution files from the magnetostatic analysis. The default behavior is to only keep the files required for postprocessing. You can use these controls to keep all files created during solution or to create and save the Mechanical APDL application database (db file).

There is no initial condition specification for a magnetostatic analysis.

• You can apply electromagnetic boundary conditions and excitations in the Mechanical application. See Electromagnetic Boundary Conditions and Excitations for details.

• Boundary conditions may also be applied on symmetry planes via a Symmetry. A Symmetry folder allows support for Electromagnetic Symmetry, Electromagnetic Anti-Symmetry, and Electromagnetic Periodicity conditions.

The Solution Information object provides some tools to monitor solution progress in the case of a nonlinear magnetostatic analysis.

Solution Output continuously updates any listing output from the solver and provides valuable information on the behavior of the structure during the analysis. Any convergence data output in this printout can be graphically displayed as explained in the Solution Information section.

Adaptive mesh refinement is available for magnetostatic analyses.

A magnetostatic analysis offers several results for viewing. Results may be scoped to bodies and, by default, all bodies will compute results for display. For Inductance or Flux Linkage, define these objects prior to solution. If you define these after a solution, you will need to re-solve.