Reusable Miniature Piezo-Magnetic Sensor for Rapid Application of Electro-Mechanical Impedance Technique on Steel Structures

Abstract In the last two decades, the electro-mechanical impedance (EMI) approach has been established as an effective technique for structural health monitoring (SHM) of civil structures. When employed in the EMI technique, piezo sensors exhibit extremely high sensitivity towards structural damage. However, the instrumentation of piezo sensors to a structure requires permanent bonding, which increases the complexity and possibility of deterioration over time. Additionally, large structures require numerous sensors, which disturb the monitoring economics. This demands an urgent development of reusable piezo sensors for an economical and effective monitoring setup. Accordingly, this paper focuses on developing magnetic reusable piezo sensors for damage monitoring using the EMI technique. In this study, three variants of the advanced reusable piezo sensor using a magnet is fabricated and investigated for damage detection and localisation on the steel plate specimen. The repeatability of all the piezo-magnetic sensors is evaluated by estimating the coefficient of correlation. Root mean square deviation (RMSD) is estimated between the healthy and damaged states to locate the damage. All the variants of piezo magnetic sensor are effectively able to capture the damage with good sensitivity.