On the modelling of a Barkhausen sensor

Persson, Gert; Chalmers University of Technology; Sweden

Persson, G.; Chalmers University of Technology; Sweden

ID: ECNDT-0308-2018
Download: PDF
Session: Modeling and data processing Electromagnetic Techniques 2
Room: J2
Date: 2018-06-12
Time: 11:30 - 11:50

A numerical model of a plain Barkhausen sensor is studied by means of the finite element method. The three-dimensional sensor consists of a magnetizing yoke, modelled as an C-core electromagnet. The planar test object is modelled as a thin plate and consisting of two or three layers, indicating a situation with a hardened layer, a transition zone and a soft layer. Simulations for the magnetic field are made for different frequencies and material combinations in the frequency plane, corresponding to a harmonic excitation of the electromagnet. All materials, including the C-core, are modelled as magnetic isotropic having a linear magnetic permeability in the constitutive relation. The magnetic flux density is computed on both on the surfaces of the planar test object and as a function of depth. The effect of lift-off is studied.