Frequency Analysis of Time Domain One Dimensional Signals and Its One Application
Satoshi NOJIMA, Yoshifuru SAITO · Journal of the Visualization Society of Japan · 2009
Ferromagnetic materials, i.e., iron steel and its composites, are widely used as the frame parts of various artificial products and constructions such as a building, bridge and so on.Because of its mechanical property, iron steel is most popular in use for the frame materials to maintain their mechanical strength.On the other side, nondestructive testing of iron steel is an extremely important way in order to keep their mechanical reliability.One of the deterministic differences between the ferromagnetic and nonmagnetic materials is that all of the ferromagnetic materials when applying external magnetic field attracts major magnetic fields; and also magnetization process of ferromagnetic materials always accompanies with the Barkhausen effect.The Barkhausen effect is a phenomenon caused by movement of the magnetic domains accompanying with the discontinuous magnetizations.In order to carry out the nondestructive testing of iron steels with high reliability, this paper proposes one of the signal cognition methodologies based on the fluctuation frequency characteristics of the Barkhausen signals.