学位論文

バルクハウゼン信号の高次周波数ゆらぎ解析

The Higher Order Frequency Fluctuation Analysis of the Barkhausen Signals

jpn

2014-03-24

Not Applicable (or Unknown)

2014-03-24

修士(工学)

工学研究科電気工学専攻; 指導教授: 齊藤兆古

Ferromagnetic materials are widely used for a lot of artificial products such as cars, trains, ships and so on. Because of its mechanical property, iron steel is most popular in use for the frame materials. Nondestructive testing of iron steel is an extremely important way to maintain their mechanical reliability. As is well known fact that Barkhausen signal is possible to emit from only the ferromagnetic materials having magnetic domain structures. And also, this signal changes its property depending upon their past mechanical as well as radioactive stress histories. In the present paper, we have applied the frequency fluctuation analysis method to the Barkhausen signals emitted from the steels and its composite materials to detect the mechanical stress difference among them. Surprisingly, it has been succeeded in clarifying that apply the frequency fluctuation analysis to the Barkhausen signal makes it possible to detect the mechanical stress difference. This fact has been confirmed by applying our method to the 30 test ferromagnetic materials. Further, environmental noise problem essentially accompanying the Barkhausen signal measurements has been taken into account by the frequency fluctuation analysis.

Thesis