Nonlinear ferromagnetic shield modelling by the thin-shell approximation

In the present paper, the case of nonlinear behaviour of the material that constitutes the shield is considered. Considering a thin layer of thickness s, having electrical conductivity s and first magnetisation or hysteretic curve B=sigmav(H), and introducing the Fixed Point technique, the values of the magnetic field inside the shield thickness can be written as a function of the values on the two faces of the shell (respectively sides (a) and (b)), plus a residual term to be iteratively computed. In Eqn. (1) [D] and [E] are constant column vectors, while [F] is a column vector including the residual nonlinearities to be updated during the iterative process.