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. 2017 Jan 3;10(1):32.
doi: 10.3390/ma10010032.

Monitoring the Damage State of Fiber Reinforced Composites Using an FBG Network for Failure Prediction

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Free PMC article

Monitoring the Damage State of Fiber Reinforced Composites Using an FBG Network for Failure Prediction

Esat Selim Kocaman et al. Materials (Basel). .
Free PMC article

Abstract

A structural health monitoring (SHM) study of biaxial glass fibre-reinforced epoxy matrix composites under a constant, high strain uniaxial fatigue loading is performed using fibre Bragg grating (FBG) optical sensors embedded in composites at various locations to monitor the evolution of local strains, thereby understanding the damage mechanisms. Concurrently, the temperature changes of the samples during the fatigue test have also been monitored at the same locations. Close to fracture, significant variations in local temperatures and strains are observed, and it is shown that the variations in temperature and strain can be used to predict imminent fracture. It is noted that the latter information cannot be obtained using external strain gages, which underlines the importance of the tracking of local strains internally.

Keywords: damage monitoring; fatigue; fibre Bragg grating; mechanical testing; polymer-matrix composites.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(a) The schematic drawing for stacking sequences together with the placement of FBG sensors and also the orientation of the cut test specimen indicated by the blue region where l, w and t indicate the length, width and the thickness of the manufactured composite plate; (b) L-shaped specimen that enables easy gripping of the test specimen by the testing system.
Figure 2
Figure 2
(a) Fatigue testing system with the data acquisition set-up; (b) the specimen E2with double axial extensometers; (c) failed specimens where failure locations are marked with the red circles and sensor locations are indicated by black vertical ticks.
Figure 3
Figure 3
Evolution of (a) temperature; (b) strain and (c) strain energy density for specimen L1 where temperature is monitored by thermocouples, while the strain data are obtained using both FBG and LVDT sensors. The letters B, M and T in subscripts refer to the sensor locations: bottom, middle and top, respectively.
Figure 4
Figure 4
Evolution of (a) temperature; (b) strain and (c) strain energy density for specimen L2.
Figure 5
Figure 5
Evolution of (a) temperature; (b) strain and (c) strain energy density for specimen L3.
Figure 6
Figure 6
Evolution of (a) temperature; (b) strain and (c) strain energy density for specimen E1.
Figure 7
Figure 7
Evolution of strain for specimen E2.
Figure 8
Figure 8
(a) Perpendicular and (b) longitudinal cross-sections of optical fibres around FBG regions.

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References

    1. Keulen C.J., Yildiz M., Suleman A. Damage Detection of Composite Plates by Lamb Wave Ultrasonic Tomography with a Sparse Hexagonal Network Using Damage Progression Trends. Shock Vib. 2014;2014:949671. doi: 10.1155/2014/949671. - DOI
    1. Cusano A., Cutolo A., Albert J. Fiber Bragg Grating Sensors: Recent Advancements, Industrial Applications and Market Exploitation. Bentham Science Publishers; Sharjah, UAE: 2011.
    1. Othonos A., Kalli K. Fiber Bragg Gratings: Fundamentals and Applications in Telecommunications and Sensing. Artech House; Norwood, MA, USA: 1999.
    1. Luyckx G., Voet E., Lammens N., Degrieck J. Strain measurements of composite laminates with embedded fibre Bragg gratings: Criticism and opportunities for research. Sensors. 2011;11:384–408. doi: 10.3390/s110100384. - DOI - PMC - PubMed
    1. Keulen C.J., Akay E., Melemez F.F., Kocaman E.S., Deniz A., Yilmaz C., Boz T., Yildiz M., Turkmen H.S., Suleman A. Prediction of fatigue response of composite structures by monitoring the strain energy release rate with embedded fibre Bragg gratings. J. Intell. Mater. Syst. Struct. 2016;27:17–27. doi: 10.1177/1045389X14560358. - DOI
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