Reluctivity characteristics in nonlinear finite element analysis of magnetostatic fields

In the finite element analysis of nonlinear magnetic materials, it is commonly convenient [1] to model reluctivity ν, the inverse of permeability µ, ask_{1} \exp (k_{2}B^{2}) + k_{3}. The constantsk_{1}, k_{2}and k3are derived by trial and error [1]. We communicate a faster and more accurate way of computing these constants systematically, by applying the Newton process to the equations for the constants. Experience with this and the other standard reluctivity curve model using spline fits [2], in finite element analysis, is also commented on.