Low Cost Impedance Monitoring Using Smart Materials

摘要

This paper presents the current research on the impedance-based structural health monitoring technique at Center for Intelligent Material Systems and Structures. The basic principle behind this technique is to apply high frequency structural excitations (typically higher than 30 kHz) through the surface-bonded piezoelectric transducers, and measure the impedance of structures by monitoring the current and voltage applied to the piezoelectric transducers. Changes in impedance indicate changes in the structure, which in turn can indicate that damage has occurred. Although many proof-of-concept experiments have been performed using the impedance methods, the impedance-measuring device is still bulky and expensive. Therefore, we have developed an operational amplifier-based turnkey device that can measure and record the electric impedance of a PZT. The performance of this miniaturized and portable device has been compared to our previous results and its effectiveness has been demonstrated. Data collected from the tests demonstrate the capability and the effectiveness of this technology to monitor the conditions of various civil structures.