Optimization of sensor design for Barkhausen noise measurement using finite element analysis

Abstract

The effects of design parameters for optimizing the performance of sensors for magneticBarkhausen emission measurement are presented. This study was performed using finite element analysis. The design parameters investigated include core material, core-tip curvature, core length, and pole spacing. Considering a combination of permeability and saturation magnetization, iron was selected as the core material among other materials investigated. Although a flat core-tip would result in higher magnetic flux concentration in the test specimen, a curved core-tip is preferred. The sensor-to-specimen coupling is thereby improved especially for materials with different surface geometries. Smaller pole spacing resulted in higher flux concentration. KeywordsBarkhausen effects, Magnetic field sensors, Coils, Magnetic materials, Magnetic fields Disciplines Electromagnetics and Photonics CommentsThe following article appeared in Journal of Applied Physics 115 (2014) The effects of design parameters for optimizing the performance of sensors for magnetic Barkhausen emission measurement are presented. This study was performed using finite element analysis. The design parameters investigated include core material, core-tip curvature, core length, and pole spacing. Considering a combination of permeability and saturation magnetization, iron was selected as the core material among other materials investigated. Although a flat core-tip would result in higher magnetic flux concentration in the test specimen, a curved core-tip is preferred. The sensor-to-specimen coupling is thereby improved especially for materials with different surface geometries. Smaller pole spacing resulted in higher flux concentration. V C 2014 AIP Publishing LLC.[http://dx

Barkhausen Noise Probes and Modelling: A Review

“…The lower saturation magnetization of the ferrite core may be one reason for the differences in the observed pickup signal with different magnetizing yokes seen in the studies of Vértesy et al [25]. Prabhu Gaunkar et al [14] verified, by means of modelling, that the magnetic flux densities vary with different core materials. They [14] noticed that, among the materials that they studied, the 78 Permalloy had the highest and the iron core had the second highest magnetic flux density values.…”

“…In the U-shape yoke, the copper coil can be wrapped in the upper area of the core. Prabhu Gaunkar et al [14] studied the effect of core length on the magnetic field and concluded, based on their modelling, that the magnetic field strength decreases with increasing core length (path length from pickup to coil). Thus, in the magnetization unit, the copper coil for magnetizing has also been wrapped around both legs as demonstrated in Fig.…”

“…Thus, in the magnetization unit, the copper coil for magnetizing has also been wrapped around both legs as demonstrated in Fig. 1a, based on Prabhu Gaunkar et al [14][15][16], or wrapped around each of four magnetizing legs as in White's tetrapole probe [8]. However, for some special cases, for example in the magnetization of a wire sample, Capo-Sanchez et al [17] reported the use of a solenoid with 700 turns of copper wire.…”

“…As Stupakov [21] concluded, the yoke core is usually chosen to be magnetically softer than the core of the sample in order to allow the magnetic field to penetrate easily and produce magnetization. In some special cases, a magnetizing yoke core made of iron has been studied [13,14,25]. The magnetization yoke in the studies of Moorthy [13] had a solid pure iron core.…”

“…The magnetization yoke in the studies of Moorthy [13] had a solid pure iron core. The permeability values depend on the composition and, in the case of iron, on the impurities, but generally ferrite has lower relative permeability values compared with iron [14]. Another important difference between the different core materials is the saturation magnetization value.…”