Abstract
This study concerns adhesion failure detection of bonded parts by utilizing a sensitive baseline-free structural health monitoring methodology referred to as nonlinear piezoelectric impedance modulation method. According to the progress of adhesion technologies, adhesion joints have been used more often replacing conventional mechanical joints such as bolted and riveted joints. Thus, a nondestructive technique which can detect and monitor the development of adhesive failures in-situ to investigate the health state of adhesive joints would be required. This technique evaluates failures in the structure under the pump eχcitation at low frequency, by demodulating the current response in amplitude and phase when a PZT patch on the surface is driven by a high frequency probe voltage source. It has distinctive features of being sensitive to incipient defects inside the structure and theoretically baseline-free because no modulation exists in a structure which has no defect. In this study, thin plate specimens with bonded parts in healthy and incomplete conditions are subjected to the probe and pump excitations, and the resultant damage evaluation indices are investigated in terms of the probe amplitudes as well as probe excitation frequencies.
