Stress Measurement Using a Magnetic Anisotropy Sensor Utilizing AC Demagnetization

The magnetic anisotropy sensor (MAS) is capable of non-contact measurement of the mechanical stress of ferromagnetic materials. This paper deals with the physical meaning of hysteresis phenomena in the MAS output voltage vs. stress characteristics of specimens (cold rolled steel). Experimental results revealed that the hysteresis of the MAS output voltage vs. stress characteristic is removed by the effect of ac demagnetizing at a field intensity HD about sixty times as large as the specimen coercivity Hc.