Characterization and local phenomenological model of Barkhausen noise under mechanical and magnetic excitations.

Post-treatment and rescaling, it is possible to plot local hysteresis cycles from the measurement of local magnetic Barkhausen noise. If the material is homogeneous and if similar excitation conditions are imposed, the local hysteresis cycles obtained are comparable to the classical magnetic hysteresis cycles B(H)(the cross-section magnetic average induction B as a function of the surface tangential excitation field H). These local Barkhausen noise hysteresis cycles give interesting clues about the evolution of the microstructure of the magnetic material (internal stresses, level of degradation etc.). This makes it an indispensable tool for the non-destructive evaluation of ferromagnetic steels. In this paper, a phenomenological modeling of the Barkhausen noise from the local modeling of B subjected to an excitation field H and/or a uni-axial mechanical stress T is proposed. The objective is to provide an absolute quantification of the internal residual stresses because of the Barkhausen noise measurements.