Bondline Integrity Monitoring of Adhesively Bonded Structures via an Electromechanical Impedance Based Approach

Author(s):  
YITAO ZHUANG ◽  
FOTIS KOPSAFTOPOULOS ◽  
FU-KUO CHANG
2017 ◽  
Vol 17 (5) ◽  
pp. 1031-1045 ◽  
Author(s):  
Yitao Zhuang ◽  
Fotis Kopsaftopoulos ◽  
Roberto Dugnani ◽  
Fu-Kuo Chang

Monitoring the bondline integrity of adhesively bonded joints is one of the most critical concerns in the design of aircraft structures to date. Due to the lack of confidence on the integrity of the bondline both during fabrication and service, the industry standards and regulations require assembling the primary airframe structure using the inefficient “black-aluminum” approach, that is, drill holes and use fasteners. Furthermore, state-of-the-art non-destructive evaluation and structural health monitoring approaches are not yet able to provide mature solutions on the issue of bondline integrity monitoring. Therefore, the objective of this work is the introduction and feasibility investigation of a novel bondline integrity monitoring method that is based on the use of piezoelectric sensors embedded inside adhesively bonded joints in order to provide an early detection of bondline degradation. The proposed approach incorporates (1) micro-sensors embedded inside the adhesive layer leaving a minimal footprint on the material, (2) numerical and analytical modeling of the electromechanical impedance of the adhesive bondline, and (3) electromechanical impedance–based diagnostic algorithms for monitoring and assessing the bondline integrity. The experimental validation and assessment of the proposed approach is achieved via the design and fabrication of prototype adhesively bonded lap joints with embedded piezoelectric sensors and a series of mechanical tests under various static and dynamic (fatigue) loading conditions. The obtained results demonstrate the potential of the proposed approach in providing increased confidence on the use of adhesively bonded joints for aerospace structures.


2018 ◽  
Vol 29 (16) ◽  
pp. 3214-3221 ◽  
Author(s):  
Piotr Fiborek ◽  
Paweł H Malinowski ◽  
Paweł Kudela ◽  
Tomasz Wandowski ◽  
Wiesław M Ostachowicz

The research focuses on the electromechanical impedance method. The electromechanical impedance method can be treated as non-destructive testing or structural health monitoring approach. It is important to have a reliable tool that allows verifying the integrity of the investigated objects. The electromechanical impedance method was applied here to assess the carbon fibre–reinforced polymer samples. The single and adhesively bonded samples were investigated. In the reported research, the electromechanical impedance spectra up to 5 MHz were considered. The investigation comprised of modelling using spectral element method and experimental measurements. Numerical and experimental spectra were analysed. Differences in spectra caused by differences in considered samples were observed.


2015 ◽  
Vol 51 (s1) ◽  
pp. 229-230 ◽  
Author(s):  
J zsef Sebastian Pap ◽  
Tom Schiefer ◽  
Irene Jansen

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