Open Access Open Access  Restricted Access Subscription Access

Growth Monitoring of Delamination and Adhesive Debonding of CFRP Structures by Rayleigh Scatting-Based Distribution Sensors



Since delamination of CFRP laminates is generated by impact or fatigue in aircraft operation, identification method of the delamination is a very important technology to ensure safety of aircraft. Recently, built-in sensors are paid attention as a real-time monitoring method of initiation and growth of delamination. Optical fiber sensors are promised as built-in sensors of FRP due to their high strength, durability and embeddability. In this paper, we applied a Rayleigh scattering-based distribution sensor to detect delamination and debonding of CFRP structures. This optical fiber sensor can measure strain distribution along a fiber with wide area range, high spatial and strain resolutions. The optical fiber sensors attached on the surface of laminates were used to detect delamination and adhesive debonding of DCB, ENF and SLJ (single lap joint) specimens. Pre-crack were formed by inserting a Teflon films between the layers or the laminate and adhesive layer during manufacturing. The experimental results of DCB tests showed that the position of delamination edge could be identified precisely from the measured sharp peak of strain distribution. From the results of ENF tests, it appeared that the strain distribution showed the maximum at the delamination edge and the detected delamination edge positions agreed very well with the observed positions. The measured strain distributions were almost same as simulated results by FEM. From the tensile test results of SLJ specimen, it appeared that strain distribution showed extremum at debonding edge. It was also shown that the measured strain distribution agreed well with simulated results by FEM. From the above results, it appeared that the open delamination and debonding could be easily identified from surface strain distribution measured by the Rayleigh scattering-based sensor.


Full Text:



Fukuda, T. and Kosaka T. 2002. “Cure and Health Monitoring,†Encyclopedia of Smart Materials,

Wiley, pp.291-318.

Konstantopoulos, S., Fauster, E. and Schledjewski, R. 2014. “Monitoring the production of FRP

composites: A review of in-line sensing methods,†eXPRESS Polymer Letters, 8(11), pp. 823–840.

Minakuchi, S., Takeda, N., Takeda S., Nagao Y., Franceschetti, A. and Liu, X. 2011. “Life cycle

monitoring of large-scale CFRP VARTM structure by fiber-optic-based distributed sensing,â€

Composites Part A, 42(6), pp.669-676.

Luyckx, G., Voet, E., Lammens, N. and Degrieck, J. 2011. “Strain measurements of composite

laminates with embedded fiber Bragg gratings: Criticism and opportunities for researchâ€,

Sensors,.11(1), pp.384-408

Kosaka, T.. 2018. “Cutting Edge of Molding Techniques of Composite Materials. Ⅲ Recent in-situ

monitoring methods of FRP molding process and their applicationsâ€, J. Soc. Mater. Sci., Japan,

(8), pp.819-825.

Di Sante, R. 2015 “Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite

Structures: Recent Advances and Applications,†Sensors, 15 ,pp.18666-18713.

Froggatt, M. and J. Moore. 1998. “High-spatial-resolution distributed strain measurement in optical

fiber with Rayleigh scatterâ€, Applied Optics, 37(10), 1735-1740.

Bao, X. and Wang., Y. 2021. “Recent Advancements in Rayleigh Scattering-Based Distributed

Fiber Sensors,†Adv. Devices & Instrumentation, 2021, Article ID 8696571.


  • There are currently no refbacks.