Non-parametric damage detection and characterization using smart piezoceramic material

The detection of damages by modal analysis and similar vibration techniques depends upon the knowledge and estimation of various modal parameters. In addition to the associated difficulties, such low-frequency dynamic response based techniques fail to detect incipient damages. Smart piezoelectric ceramic (PZT) transducers, which act both as actuators and sensors in a self-analyzing manner, are emerging to be effective in non-parametric health monitoring of structural systems. In this paper we present the results of an experimental study for the detection and characterization of damages using PZT transducers on aluminum specimens. The method of extracting the impedance characteristics of the PZT transducer, which is electromechanically coupled to the host structure, is adopted for damage detection. Three types of damage are simulated and assessed by the bonded PZT transducers for characterization. We present the effectiveness of PZT transducers in the detection and characterization of incipient damages without the need to know the modal parameters. The PZT transducers are found to have a significantly large sensing area for detecting even small incipient damages. The possibility of replicating the pristine state signatures of different transducers under similar conditions of bonding and geometrical location is also explored. For appropriate characterization of damages, a few statistical signature pattern recognition techniques are evaluated.