Mechanical impedance based embedded piezoelectric transducer for reinforced concrete structural impact damage detection: A comparative study

Electromechanical admittance (inverse of impedance) based nondestructive evaluation method has been extensively applied to damage detection and health monitoring of engineering structures. This paper proposed an innovative method of using the effective structural mechanical impedance (ESMI) to detect reinforced concrete (RC) structural damages. ESMI based method was first formulated based on a generic two-dimensional model for embedded piezoelectric (PZT) transducer interacting with a host structure. And structural mechanical impedance (SMI) based method using a typical one-dimensional PZT-structure interaction model was also briefly introduced. Validation of the proposed method was investigated in an experiment of testing a RC beam structure with different levels of impact damages, in which raw admittance signatures measured from three embedded PZT transducers were used for extracting ESMI and SMI signatures. Sensitivity of ESMI, SMI and admittance signatures was then qualitatively compared in detecting RC beam structural damages. Additionally, these three signatures based damage quantification was also conducted using two-types of statistical root mean square deviation (RMSD) indices. Results demonstrated that the ESMI signature exhibits well performance in detecting the RC beam structural impact damage. The proposed method provides a promising alternative for precise prediction of RC structural damage especially when the PZT transducers embedded inside structures.