Characterization of the Electromechanical Admittance Signatures of Piezo-Impedance Transducers based on its Location

Abstract

Abstract The Electromechanical Impedance method (EMI), using piezoelectric ceramics transducers such as Lead-Zirconate-Titanate (PZT), has applications in the fields of non-destructive evaluation (NDE) and structural health monitoring (SHM). The piezo-ceramic transducer chip (PZT) serves as an actuator supplying vibrational energy when it is bonded to the structure and subjected to harmonic voltage at ultrasonic frequency ranges. The electrical admittance of the PZT is known to be dependent on the dynamic coupling of the mechanical impedances of the PZT and the host structure. The admittance signature obtained over a frequency range serves as a diagnostic signal to monitor structural health. Any defect or damage changes the structure’s mechanical impedance which gets reflected in the admittance signature. This paper examines the changes in the admittance signatures of the same PZT transducer when it is bonded at different locations of a thin plate with cantilever type end conditions. The study is purely numerical using the coupled-field FE simulations in ANSYSTM, yet it gives better insight into admittance signature analysis, which is essential to assessing the structural health.