Wong, V.-K., Liu, M., Goh, W.-P., Chen, S., Zheng Wong, Z., Cui, F., & Yao, K. (2022). Structural health monitoring of fastener hole using ring-design direct-write piezoelectric ultrasonic transducer. Structural Health Monitoring, 147592172110739. https://doi.org/10.1177/14759217211073950
Fatigue cracks initiated from fastener holes are common in aircraft structures. Implementation of effective structural health monitoring (SHM) system to detect or monitor fatigue cracks near fastener holes is desired for realizing condition-based maintenance with improved aircraft safety at reduced cost. In this work, direct-write piezoelectric ultrasonic transducers were used for monitoring crack near fastener hole. Made of poly (vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)] film and annular array electrodes, the direct-write piezoelectric ultrasonic transducers were both directly coated and patterned around the fastener holes. A novel ring-design using annular array electrodes with small footprint was proposed to detect fatigue crack initiated in the vicinity of a fastener hole using pulse-echo and pitch-catch methods. The ring-design direct-write piezoelectric ultrasonic transducers were designed to operate with Lamb wave modes at 1.5 MHz. A numerical simulation study was conducted to investigate the interaction of Lamb wave modes with the fatigue crack. Experimental ultrasonic testing was performed with signal gates determined using wavelet analysis. Fatigue crack detection was demonstrated using an energy ratio method by comparing energy parameter of gated ultrasonic signal with baseline signal. Using the pulse-echo method, the direction of the fatigue crack was able to be determined. The pitch-catch method was found to have higher sensitivity in fatigue crack detection but could not determine the direction of the fatigue crack. These transducers made of thin films promise high conformability even on curved surface and around irregular objects with limited space, compared to conventional discrete ultrasonic transducers. The analysis and results showed that the ring-design direct-write piezoelectric ultrasonic transducers have great potential for fastener hole SHM.
This research / project is supported by the Agency for Science, Technology and Research (A*STAR) - RIE2020 AME Industry Alignment Fund - Pre-positioning Programme (IAF-PP)
Grant Reference no. : A20F5a0043
This research is supported by core funding from: RIE2020 AME Core Funds-SERC Strategic Funds
Grant Reference no. : A1718g0056
The Contribution has been accepted for publication in the journal. The article information as follows:
Wong, V.-K., Liu, M., Goh, W.-P., Chen, S., Zheng Wong, Z., Cui, F., & Yao, K. (2022). Structural health monitoring of fastener hole using ring-design direct-write piezoelectric ultrasonic transducer. Structural Health Monitoring, 147592172110739. (2022). https://doi.org/10.1177/14759217211073950