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Optical Fiber Sensors for Aircraft Structural Health Monitoring.

García I, Zubia J, Durana G, Aldabaldetreku G, Illarramendi MA, Villatoro J - Sensors (Basel) (2015)

Bottom Line: Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors.Several practical applications for structures and engines we have been working on are reported in this article.With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

View Article: PubMed Central - PubMed

Affiliation: Department of Communications Engineering, E.T.S.I. of Bilbao, University of the Basque Country UPV/EHU, Alda. Urquijo s/n Bilbao 48013, Spain. iker.garciae@ehu.eus.

ABSTRACT
Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

No MeSH data available.


Related in: MedlinePlus

Calibration curve of the sensor showing the two possible regions of measurement: region I (front-slope) in blue and region II (back-slope) in red.
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sensors-15-15494-f018: Calibration curve of the sensor showing the two possible regions of measurement: region I (front-slope) in blue and region II (back-slope) in red.

Mentions: The central fiber guides the light from a laser module connected at leg 1 to the probe end, so that the blades of the turbine are illuminated. This fiber is surrounded by two rings of receiving fibers which collect the reflected light from the blades. The set of receiving fibers corresponding to the first ring (6 fibers) and the second ring (12 fibers) are gathered in bundle legs 2 and 3, respectively. At the end of these legs two photodetectors are connected to convert the optical signals into voltage. The distance from the sensor tip to the blade is calculated from the quotient of these voltages to minimize the effects of fluctuations of the light source or variations in the reflectivity of the surface [68,69]. Detailed information about the configuration of the sensor and the set-up to perform the measurements is provided in [70]. The calibration curve of the sensor is depicted in Figure 18. Previous works carried out the measurements using the front-slope region (region I), whereas our sensor operates in the back-slope region (region II). In this region, there is a trade-off between the sensitivity of the sensor and its linear range, so that the TC can be measured for larger distances but with lower sensitivity.


Optical Fiber Sensors for Aircraft Structural Health Monitoring.

García I, Zubia J, Durana G, Aldabaldetreku G, Illarramendi MA, Villatoro J - Sensors (Basel) (2015)

Calibration curve of the sensor showing the two possible regions of measurement: region I (front-slope) in blue and region II (back-slope) in red.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541841&req=5

sensors-15-15494-f018: Calibration curve of the sensor showing the two possible regions of measurement: region I (front-slope) in blue and region II (back-slope) in red.
Mentions: The central fiber guides the light from a laser module connected at leg 1 to the probe end, so that the blades of the turbine are illuminated. This fiber is surrounded by two rings of receiving fibers which collect the reflected light from the blades. The set of receiving fibers corresponding to the first ring (6 fibers) and the second ring (12 fibers) are gathered in bundle legs 2 and 3, respectively. At the end of these legs two photodetectors are connected to convert the optical signals into voltage. The distance from the sensor tip to the blade is calculated from the quotient of these voltages to minimize the effects of fluctuations of the light source or variations in the reflectivity of the surface [68,69]. Detailed information about the configuration of the sensor and the set-up to perform the measurements is provided in [70]. The calibration curve of the sensor is depicted in Figure 18. Previous works carried out the measurements using the front-slope region (region I), whereas our sensor operates in the back-slope region (region II). In this region, there is a trade-off between the sensitivity of the sensor and its linear range, so that the TC can be measured for larger distances but with lower sensitivity.

Bottom Line: Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors.Several practical applications for structures and engines we have been working on are reported in this article.With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

View Article: PubMed Central - PubMed

Affiliation: Department of Communications Engineering, E.T.S.I. of Bilbao, University of the Basque Country UPV/EHU, Alda. Urquijo s/n Bilbao 48013, Spain. iker.garciae@ehu.eus.

ABSTRACT
Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

No MeSH data available.


Related in: MedlinePlus