How do Integrated Programs Handle Nonlinear (Irreversible) Magnetic Materials?
Magnetic materials generally have a nonlinear and history dependent B-H magnetization characteristic, as illustrated in the generic hysteresis curve to the right. However, for practical purposes magnetic materials can usually be considered as one of two types: • Red curve: ferromagnets (e.g. steels), paramagnets, and diamagnets • Blue curve: permanent magnets The Material Editor screen capture to the right shows the material types for “Parameter: Permeability” corresponding to the descriptions above. Ferromagnets can be Linear (permeability only) or Nonlinear (B-H magnetization curve). Paramagnets and diamagnets are linear. They are specified by relative permeability or susceptibility. The input boxes are linked by formula as: χ = µr – 1 and µr = χ + 1 Many materials cross the second quadrant reversibly along a straight line. These can be modeled as shown to the right by inputting the axis points Br and Hc. In some other cases the behavior is linear and reversible enough over the range
