Finite element analysis of unbounded non-linear transient magnetic fields

This paper presents an iterative FEM procedure for the solution of unbounded non-linear transient magnetic field problems. The boundlessness of the domain is dealt with by introducing a fictitious boundary defining a bounded region. At each discrete time, by assuming a first guess for the Dirichlet condition on such a boundary a standard FEM solution for the bounded non-linear transient problem is carried out; the results of the FEM analysis are used to update the Dirichlet condition on the fictitious boundary; the above steps are then iterated until a solution to the unbounded problem is reached. The procedure is rapidly convergent, accurate and easy to implement.