Abstract
The authors have proposed a corrosion damage evaluation method for corroded steel members to estimate rust layer and residual thickness. In this method, detected voltage signal obtained by a low frequency eddy current of 500 Hz or less was used as an index. In this research, in order to further advance the method and to simplify the measurement system, a more sophisticated method utilizing a phase characteristic which is considered to be able to simultaneously estimation of thickness information together with the detected voltage has been investigated. Firstly, to clarify the low frequency eddy current characteristics assuming the difference in damaged condition by numerical simulation was performed. Then evaluation method focusing on the phase between the detected voltage and the input current and the detected voltage as an index to capture the differences has investigated. Based on results of all process, a corrosion damage evaluation method focused on phase characteristics which can obtain information of rust layer and residual thickness simultaneously was proposed. Finally, the applicability of proposed method was clarified by experiment.
