Experimental and analytical identification of a delamination using isolated PZT sensor and actuator patches

ABSTRACT: Delaminations in laminated composite structures are usually invisible or difficult to detect by visual inspection, and thus, cost-effective and reliable non-destructive techniques and approaches need to be developed to detect such failures for structural health monitoring. In this study, a dynamic analytical model is developed to detect a through-the-width delamination embedded in a cantilever laminated composite beam. This beam is surface-bonded with an isolated piezoelectric lead-zirconate-titanate (PZT) sensor and a PZT actuator. The PZT actuator located near the fixed end of the composite beam is used to excite the beam system using a sinusoidal input voltage. The PZT sensor with a striped electrode pattern is bonded on the top surface of the beam section embedded with a delamination and is used to monitor the output voltages recorded from the electrode strips. To study the feasibility of the present model for delamination identification, an experimental investigation is conducted to detect an embedded delamination using this PZT sensor and actuator setup. A comparison of the first three frequencies and the output voltage distribution for the case of the first frequency between the predicted and measured results is carried out, and good agreement between them is noted. Numerical study using the present analytical model reveals that the output voltage distribution along the PZT sensor is closely related to the magnitude and frequency of the sinusoidal input voltage. KEY WORDS: dynamic analytical model, delamination identification, composite beam, output voltage distribution, piezoelectric lead-zirconate-titanate (PZT) sensor and actuator