Output Voltage-Excitation Frequency Characteristics of Magnetic Anisotropy Sensor

The magnetic anisotropy sensor (MAS) is a stress sensor that detects internal stresses induced by the inverse magnetostrictive effect. In this study, the sample is a cold rolled steel plate used in a car body. For flux penetration depths greater than the sample thickness (0.75 mm), the MAS detects the average of the internal stress distribution, producing an output voltage related to the internal stress distribution. The flux density distribution in the sample caused by skin effect varies with the excitation frequency. This paper shows that the internal stress distribution can be estimated from the output voltage vs. excitation frequency characteristic.