Damage Identification in Aging Aircraft Structures with Piezoelectric Wafer Active Sensors

Abstract

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-R 2 ) 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.

Structural health monitoring by extraction of coherent guided waves from diffuse fields

“…SHM methods based on ultrasonic guided stress waves are particularly suitable for probing components with waveguide geometries, such as the skin panels of aircraft fuselage and wings (Rose, 1999;Giurgiutiu et al, 2004;Lanza di Scalea et al, 2007).…”

Enhanced Composites Integrity Through Structural Health Monitoring

“…The sensitivity of nonlinear methods in detecting damage (cracks, flaws) is reported to be far greater than that of linear acousto-ultrasonic methods (measures of wave speed and wave dissipation) [15][16][17]. The nonlinear methodologies also can coexist with Lamb wave based methods.…”

Damage assessment in concrete structures using piezoelectric based sensors

“…By comparing the impedance signature taken in the pristine state and at any other time, structural damage can be determined. Generally, both frequency and amplitude shifts are produced relative to the pristine state (without damage) (Ayres et al, 1998;Chaudhry et al, 1995;Sun et al, 1995;Park et al, 2000;Zagrai and Giurgiutiu, 2001;Giurgiutiu et al, 2002Giurgiutiu et al, , 2004Peairs et al, 2004;Narayanan and Subramaniam, 2016a). Application of EMI technique for damage detection in concrete structures requires a careful study of the changing compliance of the substrate for different forms of damage in the substrate material from the incipient to the visible stages.…”