APPLICATION OF PIEZOELECTRIC IMPEDANCETECHNOLOGY IN STRUCTURAL DAMAGE DETECTION

摘要

Recently, the impedance-based damage detection techniquehas been developed as a promising tool for real-timestructural damage assessments. The basic concept of thismethod is using the electromechanical coupling property, inwhich the electrical impedance of piezoelectric materials isdirectly related to the mechanical impedance of the hoststructure. Through detection the measured electricalimpedance and comparing it with a reference measurement,we can qualitatively determine structural damage is starting orhas already been occurred. However, it usually needs highquality impedance analyzer for detecting very small damage.Moreover, laboratory-type impedance analyzers are bulky,heavy, and relatively expensive. They can not easily carriedinto the field for on-site structural damage detection. In thispaper, we develop a field-portable small-size impedancemeasurement system for structural damage detection. Thesystem consists of a rectangle wave generator, computer, ADconverter and piezoelectric element. We present someexperimental results for testing the torque loose in the bolt fora truss structure. The results indicate that an accuracy of theimpedance measurement system proposed in this paper isalmost as accurate as the commercial multipurposeimpedance analyzer. It could be used on the structures fordamage detection, and for very small damage.