Influence of piezoelectric parameters on admittance diagnostic signals for structural health monitoring: a numerical study

The electromechanical impedance (EMI) technique for structural health monitoring (SHM) relies on the analysis of the electrical admittance response, known as the admittance signature, of a piezoelectric ceramic (PZT) chip bonded on or embedded within a structure. Damage in the structure alters its mechanical impedance. Owing to the dynamic coupling that exists between the mechanical impedances of the structure and the PZT chip, this is in turn reflected in the changed admittance signature. The changes in the admittance signature due to deterioration of the PZT characteristics need to be distinguished from those due to structural damage for effective SHM. This paper presents the results of a numerical study carried out to understand the influence of PZT material parameters and geometric characteristics on the admittance signature, which may be useful for effective analysis of diagnostic signals for SHM purposes.