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Damage detection in concrete structures using a simultaneously activated multi-mode PZT active sensing system: numerical modelling

In this study, a structural health monitoring approach that integrates both electromechanical admittance (EMA) and guided wave (GW) techniques is presented. More specifically, the EMA technique is used for local damage identification, by employing a piezoelectric transducer (PZT) as admittance sensor. Simultaneously, the same admittance sensor is disturbed by selected elastic GWs launched by another PZT to monitor the damages located beyond the sensing area of the admittance sensor. The validation of the integrated approach is achieved by identifying the changes in electrical admittance signatures as measured on the surface electrodes of PZTs. These changes occur when damage alters the mechanical impedance of the examined concrete structure and when propagating GWs encounter structural damage. Finite element models of damages occurring in conventional unreinforced, steel-reinforced or fiber reinforced plastics-reinforced concrete specimens are investigated. Results illustrate that the proposed integrated technique is an efficient approach for damage identification of concrete structures.