Magnet (unidirectional): spline demagnetization curve

Presentation

This model ( Nonlinear magnet described by a spline ) defines a magnet with a nonlinear B(H) characteristic starting from experimental B, H values.

The definition of the B(H) behavior law with this model is a little longer than with the analytic models, but the experimental curve is modeled more accurately.

Main characteristics:

  • the mathematical model and the direction of magnetization are dissociated
  • a single material for description of several regions

Mathematical model

In the direction of magnetization the model is constructed in the following manner:

  • entry of experimental B, H values
  • interpolation by a spline function
The shape of the B(H) dependence in the direction of magnetization is given in the opposite figure.

In transversal directions , one can write:

B⊥(H)= μ0μr⊥H⊥

where μr⊥ is the transverse relative permeability