Magnetic hysteresis and magnetic flux patterns measured by acoustically stimulated electromagnetic response in a steel plate

Abstract

Magnetic hysteresis loops are measured by ultrasonic techniques and used in visualizing the magnetic-flux distribution in a steel plate. The piezomagnetic coefficient determines the amplitude of acoustically stimulated electromagnetic (ASEM) fields, yielding the hysteresis behavior of the intensity of the ASEM response. By utilizing the high correspondence of the ASEM response to the magnetic-flux density, we image the specific spatial patterns of the flux density formed by an artificial defect in a steel plate specimen. Magnetic-flux probing by ultrasonic waves is thus shown to be a viable method of nondestructive material inspection.

Phase-sensitive detection of acoustically stimulated electromagnetic response in steel

“…The hysteresis behavior is almost the same as the results reported in our earlier studies. 13) The minimum observed at ±H min = ±4 kA=m indicates a demagnetized condition. 00 ðHÞ is almost absent in the whole applied magnetic field region.…”

“…[14][15][16] In this paper, we focus on the magnetic hysteresis curve of ASEM signals in steel. In our earlier study, 13) the hysteresis curve was obtained by measuring the amplitude of ASEM waves. Namely, the phase delay was neglected.…”

Flaw Detection for Thin Sheet Using Acoustic Stimulated Electromagnetic Wave Technique

“…Based on these advantages, we have previously demonstrated the detection of an artificial defect (a through hole 1 mm in diameter) using the ASEM wave technique. 4) In addition, the detection of a smaller defect (0.3 mm in diameter) has been also reported. 9) In this paper, we improve the signal-to-noise ratio (SNR) using a small coil antenna and detect a through hole 0.1 mm in diameter.…”

“…The magnetic properties of steel are changed by strain, 6) and the relationship between the ASEM response signal and the B − H characteristics have been reported previously. 4,5) The ASEM waves are observed even if there are no flaws or defects. The magnetic field dependence of the ASEM signal intensity is shown in Fig.…”

“…[1][2][3] Biomedical applications have been investigated and industrial applications are also promising. 4,5) In biological tissues such as bone, the electric field modulation due to piezoelectricity generates the ASEM waves. In ferromagnetic metals such as steel, the magnetic field modulation due to piezomagnetism (or magnetostriction) 6) is an important factor in the ASEM wave generation.…”