Experimental detection of debonding of piezoelectric sensors with the segmented electrode

Abstract

The piezoelectric transducers (PZT) are bonded to smart structures by means of an intermediate adhesive layer, with the main objectives of applying methodologies of structural health monitoring, nondestructive evaluation, nondestructive inspection and structural control to the structures. However, the application of these methodologies depends on the health of the adhesive joint that couples mechanically the PZT with the structure. This research shows an experimental technique based on the segmentation of electrodes of a PZT patch in sheet form. One electrode is segmented in three equal parts (end left, middle and end right) to obtain three electrical signatures of a PZT. The electrical signatures (voltage) of the end electrodes are related to the middle electrode voltage. Three experiments were carried out in this study: two static cases and one dynamic case. For the static case, the left end (first case) and the right end (first case) were debonded. In the dynamic case, only one side was debonded. The results show that the voltage relations present linear behavior and the changing in the slope of the voltage ratio allows identifying which electrode is debonded. This technique showed to be effective in the three studied cases of debonding and it could be used to identify debonding in real time.