Enhanced modeling of magnetic impedance sensing system for damage detection

摘要

There has been recent interest in utilizing the magneto-mechanical coupling characteristics of a magnetic transducer to perform impedance-based damage detection of electrically conductive structures. This approach is non-contact in nature and has potential advantages in many applications. One important parameter in this approach is the lift-off distance, i.e. the distance from the transducer to the structure monitored, the change of which changes the magneto-mechanical coupling. In the past, the magneto-mechanical coupling is extracted completely or partially from experiment in an ad hoc manner. A predictive capability of magneto-mechanical coupling under given lift-off distance would play a significant role in damage detection practice and in sensor design/optimization. In this research, we formulate detailed first-principles-based modeling of a magnetic impedance transducer. In particular, the complete electrical effect of the structure is explicitly taken into consideration. Comprehensive analyses and experiments are carried out, which validate the underlying hypothesis as well as the accuracy of the new model proposed for impedance response prediction.