Low-cost electromechanical impedance testing damage detection of submerged civil structures

Electromechanical (E/M) impedance testing using piezoceramic (PZT) patches adhered to the surface of a substrate structure is regarded as a promising structural health monitoring (SHM) technique due to its ability to detect local and incipient damage in diverse types of structures. E/M impedance testing utilizes the direct/inverse piezoelectric effect, and the PZT patch acts as both sensor and actuator. Any damage done to the substrate structure will change its mechanical impedance, thus further changing the coupled electromechanical impedance of the patch-structure system, which can be measured using impedance analyzers. Research in this field so far has largely been laboratory-based in ideal environmental conditions with impedance measurements taken using bulky and expensive commercial impedance analyzers. Moreover, little has been done for structures submerged in water. This paper investigates the potential for using low-cost electromechanical impedance analyzers for damage detection in submerged civil structures. The goal is to close the critical gap between laboratory development of the E/M impedance testing method and its deployment in the field. A single-board computer (SBC), called Red Pitaya (RP), is used to make high-fidelity impedance measurements and wirelessly communicate with a PC. Damage detection tests are established on steel beams to test RP's efficacy as a SHM tool. Damage detection tests on beams are conducted on submerged specimens and the results demonstrate the potential of using RP for detecting damage in submerged civil structures using low-cost impedance testing.