Optimal Frequency Range Selection for PZT Transducers in Impedance-Based SHM Systems

TLDR

Piezoelectric PZT transducers are widely used in SHM systems based on electromechanical impedance, where damage is detected by measuring impedance over a suitable frequency range, but selecting that range is usually done by trial and error. This paper proposes a formal procedure to determine the frequency ranges in which PZT transducers are most sensitive for damage detection. The method derives optimal frequency ranges by analyzing the transducer’s impedance response and its sensitivity to structural damage. Tests on specimens of varying sizes showed a strong agreement between theoretical predictions and experimental measurements.

Abstract

Piezoelectric transducers of PZT (lead zirconate titanate) have been widely used in structural health monitoring (SHM) systems based on the electromechanical (E/M) impedance technique. In this technique, damages in the structure are identified by measuring the electrical impedance of the transducer in an appropriate frequency range. Usually, the selection of the correct frequency range to detect and evaluate damage is obtained by trial and error methods. In this paper, it is proposed a formal procedure to determine the frequency ranges in which the PZT transducers are more sensitive for damage detection. Tests were carried out on specimens with different sizes and there was a good match between the theoretical and practical results.