History data free piezoelectric based non-destructive testing technique for debonding detection of composite structures

In this study, a possibility of detecting debonding of composite structures without an onsite reference signature is presented. The approach is based on the electromechanical impedance (EMI) technique which can be created into a compact system, light and reliable enough to be equipped even onto an unmanned aerial vehicle (UAV). To make this idea possible, the piezoelectric (PZT) materials was modified to be able to attach and re-attach temporarily onto a structure surface. Although that reattaching the PZT transducer caused the signature to changed, it was found that the peak amplitude height of the impedance signatures were similar for certain thickness composites. From this, it was possible to propose an idea of creating a process of detecting debonding of composites without the need for the onsite reference impedance signature. Both experimental and simulation results are obtained to verify the presented concept where promising outcome has been shown.