Recent advances in the use of piezoelectric wafer active sensors for structural health monitoring
by
Victor Giurgiutiu
Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA
Coauthors: Dustin Thomas, John Welter, John Barnes, Air Force Research Lab, NDE Branch, Wright-Patterson AFB, OH 45433-7817, USA

Piezoelectric-wafer active sensors (PWAS) are small, inexpensive, non-invasive, elastic wave generators/receptors that can be easily affixed to a structure. Piezoelectric-wafer active sensors are wide-band non-resonant devices. They can be wired into sensor arrays and connected to data concentrators and wireless communicators. They have the potential to bring about a revolution in structural health monitoring, damage detection, and non-destructive evaluation just as significant as ultrasonic inspection did 50 years ago. However, its development is not yet complete, and a number of issues have still to be resolved. This paper will present recent advancements obtained by the authors in using the PWAS for structural health monitoring. Two directions will be explored: (a) the tuned traveling Lamb waves approach using the pitch-catch and the pulse echo methods, and (b) the broadband standing Lamb wave approach using the high-frequency electromechanical (E/M) impedance method.

In the tuned traveling Lamb-waves approach we will present resent results obtained in the detection of cracks with the pulse-echo method and the detection of corrosion with the pitch-catch method. For crack detection, tuned S0 Lamb waves were used, since this wave type seems to be more sensitive to through-the-thickness cracks. For corrosion detection, tuned A0 Lamb waves were used, since these type of waves seems to be more sensitive to thickness changes due experienced during corrosion progression. For the same reason, tuned A0 Lamb modes were found useful in the detection of disbonds and delamination. Another result of the traveling Lamb-waves approach to be presented is the embedded ultrasonics structural radar (EUSR). Recent advances in this direction encompasses advanced signal processing and the verification of its applicability to curved shell panels. In the broadband standing Lamb-waves approach, we will present the E/M impedance technique in the near-field detection of crack, corrosion, and delaminations.

The paper will finish with a summary of the presented work and a perspective for further research and industrial implementation.

Date received: November 13, 2003

Copyright © 2003 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cama-60.