FEM analysis of the magnetic field for B-H relationship evaluation

The properties of some ferromagnetic materials are known by measurements made on samples using adequate instruments, and are offered by manufacturers or databases. The evaluation of unknown magnetic characteristics of ferromagnetic bodies cannot be directly made, due to the impossibility of collecting material samples. However, the B-H characteristics of these bodies influence the nearby field in the air. Thus one can pose the inverse problem of B-H relationship determination by making measurements of the magnetic flux density in the neighborhood of the piece. One must use a sensitive computation procedure in order to obtain accurate results. In this paper a device is proposed for evaluating the B-H characteristic. Several device geometries are considered in order to determine the one giving the most accurate results and having the best sensitivity.