Damage Identification in Aging Aircraft Structures with Piezoelectric Wafer Active Sensors
Engineering, Mechanical Engineering
Piezoelectric wafer active sensors can be applied to aging aircraft structures to monitor the onset and progress of structural damage such as fatigue cracks and corrosion. Two main detection strategies are considered: (a) the wave propagation method for far-field damage detection; and (b) the electro-mechanical (E/M) impedance method for near-field damage detection. These methods are developed and verified on simple-geometry specimens, and then tested on realistic aging-aircraft panels with seeded cracks and corrosion. The specimens instrumentation with piezoelectric-wafer active sensors and ancillary apparatus is presented. The experimental methods, signal processing, and damage detection algorithms, tuned to the specific method used for structural interrogation, are discussed. In the wave propagation approach, the pulse-echo and acousto-ultrasonic methods were considered. Reflections from seeded cracks were successfully recorded. In addition, acoustic emission and low-velocity impact were also detected. In the E/M impedance method approach, the high-frequency spectrum is processed using overall-statistics damage metrics. The (1-R2 ) 3 damage metric, where R is the correlation coefficient, was found to yield the best results. The simultaneous use of the E/M impedance method in the near field and of the wave propagation method in the far field opens the way for a comprehensive multifunctional damage detection system for aging aircraft structural health monitoring.
Postprint version. Published in Journal of Intelligent Material Systems and Structures, Volume 15, Issue 6, 2004, pages 673-687.
© Journal of Intelligent Material Systems and Structures, 2004, SAGE Publications
Giurgiutiu, V., Zagrai, A., Bao, J. (2004). Damage Identification in Aging Aircraft Structures with Piezoelectric Wafer Active Sensors. Journal of Intelligent Material Systems and Structures, 15(6), 673-687.