Diagnostic Model of Hysteresis for Condition Monitoring of Large Construction Structures

The conception of diagnostics, based on passive magnetic field measurements is being presented. It was shown that the transformation of the signal to the appropriate form of hysteresis, creates new potential for identifying changes in signal parameters that correspond to specific physical phenomena. Model supported analysis of changes in the magnetic field, made it possible to obtain diagnostic parameters characterizing magnetomechanical hysteresis, which can be used in determining the state of the material strain on the object structure subjected to variable loads. Suitable model of hysteresis was elaborated and conditions in which it could be applied were stated. Obtained by authors diagnostic parameter confirm the validity of the hysteresis model used for this case. The chapter concludes that state of polarization of the magnetic structure (the distribution of magnetization) is carrier of diagnostic information about the level of effort and the progressive degradation of the material structure. It is possible to obtain the diagnostic information through a remote, non-contact measurement of magnetic field near the test structure.