Electromechanical impedance based intelligent corrosion sensing and monitoring method for steel structures

Abstract Corrosion induced steel loss is the primary cause for the failure and destruction of steel structures. The electromechanical impedance (EMI) based circular piezoelectric-metal transducer as corrosion sensor, featuring corrosion-sensitivity in its resonance, has been proven to be promising corrosion sensing technique. In this paper, the comprehensive performance testing in terms of sensitivity, sensor encapsulation, temperature compensation, low-cost wireless monitoring system and its integration, and in-situ application, were examined. Firstly, based on the linear piezoelectric elasticity theory and the Kirchhoff thin plate assumption, a theoretical model of EMI for the circular piezoelectric-metal laminated structure was derived. Secondly, finite element analysis and experiments were carried out to validate the corrosion sensing mechanism and investigate its response under accelerated corrosion tests. Thirdly, to achieve high durability, the packaging structure of the sensor was designed and tested. Lastly, a wireless impedance monitoring system (WIMS) was developed and its performance was examined in in-situ corrosion monitoring of a steel structure. The results demonstrated that the proposed new corrosion sensor and the WIMS enable linear, quantitative, and online corrosion sensing and monitoring.