Dual piezoelectric transducer based electromechanical impedance measurement for health monitoring of large structures

Abstract

This study presents an electromechanical (EM) impedance measurement technique using a dual piezoelectric transducer for continuous monitoring of large structures. The dual piezoelectric transducer, composed of two separate but concentric lead zirconate titanate (PZT) segments, can effectively measure the small response of the host structure, since it is not influenced by the excitation-induced PZT strain. The proposed EM impedance measure-ment technique shows high signal-to-noise ratio (SNR) and good repeatability from the measured impedance signals in massive structures. At the same time, the proposed technique allows low-cost and fast measurement of the impedance signatures. In this study, the dual PZT impedance measurement is formulated theoretically and verified numerically. Then, a series of experimental validation were carried out on a laboratory-size specimen and full-scale bridge and building structures. The experimental results show that the proposed technique successfully measures the EM impedance signals with high SNR and good repeatability from massive structures even in which the conventional techniques fail to do so.