An enhanced piezoelectric impedance approach for damage detection with circuitryintegration

Abstract

Due to their two-way electromechanical coupling, piezoelectric transducers can be used forimpedance or admittance-based damage detection, in what is hereafter referred to as thepiezoelectric impedance-based approach. Such an approach has been recognized as beingsensitive to small-sized damage, as the piezoelectric impedance or admittance can bemeasured at relatively high frequencies. In an earlier work we have demonstrated thatintegrating a tunable inductor with the piezoelectric transducer to form an inductiveresonant circuit can amplify both the admittance measurement magnitude and thedamage-induced admittance anomaly. In this research, we investigate furtherenhancing the piezoelectric impedance approach for damage detection by means ofcircuitry integration. In particular, we introduce a negative capacitance element intothe inductive circuitry, and then explore an alternative circuitry topology. It isdemonstrated that the negative capacitance can broaden the measurement amplificationeffect due to the circuitry resonance to a much wider frequency range, therebyincreasing the damage detection accuracy and sensitivity. It is also verified that,compared to the previous serial connection between the inductor and the resistor(used to facilitate the admittance measurement), a parallel connection of thesetwo elements can amplify the voltage drop across the resistor, which increasesthe signal-to-noise ratio in the sensor measurement. Extensive numerical andexperimental studies are carried out to illustrate the effectiveness of our proposedenhancements.