Limits...
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

Wavelength variations due to the strain in the tail boom provided by the first FBG during the three fatigue cycles.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4541841&req=5

sensors-15-15494-f010: Wavelength variations due to the strain in the tail boom provided by the first FBG during the three fatigue cycles.

Mentions: The results obtained by the POF elongation sensor for several load cycles can be observed in Figure 9. When a force of 0.75 kN or 0.5 kN is applied, the cycles are clearly detected by the sensor. However, for the case of 0.25 kN the noise makes it impossible to distinguish the stress cycles in the post-processed signal. The goal of these tests was to demonstrate the capability of the POF elongation sensor to detect the load cycles on the tail boom. Although this goal was achieved, more tests should be carried out to ensure the reliability of the sensor, and the quality of the output signal must be improved. The offset variations in the displacement signals are due to the drift of the modulation frequency provided by the VCO, which is interpreted by the phase comparator as a change in the phase of the received signals. Hence, the VCO performance must be optimized to stabilize the modulation frequency and avoid changes in the offset of the output signal. Another way to improve the POF elongation sensor would be to bond the reference fiber on the outer surface of the tail boom, so that the phase difference between the two optical signals would increase. Thus, increasing the sensitivity of the sensor. For the sake of comparison, the results obtained for one of the FBGs are plotted on Figure 10. The signals are obviously less noisy than those of the POF elongation sensor. The strain in the structure is represented by the changes of the reflected wavelength in the FBG for the three applied forces. As expected, the strain given by the FBG placed in the perpendicular direction of the tail boom is noticeably smaller than the ones provided by the FBG placed longitudinally.


Optical Fiber Sensors for Aircraft Structural Health Monitoring.

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

Wavelength variations due to the strain in the tail boom provided by the first FBG during the three fatigue cycles.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-15494-f010: Wavelength variations due to the strain in the tail boom provided by the first FBG during the three fatigue cycles.
Mentions: The results obtained by the POF elongation sensor for several load cycles can be observed in Figure 9. When a force of 0.75 kN or 0.5 kN is applied, the cycles are clearly detected by the sensor. However, for the case of 0.25 kN the noise makes it impossible to distinguish the stress cycles in the post-processed signal. The goal of these tests was to demonstrate the capability of the POF elongation sensor to detect the load cycles on the tail boom. Although this goal was achieved, more tests should be carried out to ensure the reliability of the sensor, and the quality of the output signal must be improved. The offset variations in the displacement signals are due to the drift of the modulation frequency provided by the VCO, which is interpreted by the phase comparator as a change in the phase of the received signals. Hence, the VCO performance must be optimized to stabilize the modulation frequency and avoid changes in the offset of the output signal. Another way to improve the POF elongation sensor would be to bond the reference fiber on the outer surface of the tail boom, so that the phase difference between the two optical signals would increase. Thus, increasing the sensitivity of the sensor. For the sake of comparison, the results obtained for one of the FBGs are plotted on Figure 10. The signals are obviously less noisy than those of the POF elongation sensor. The strain in the structure is represented by the changes of the reflected wavelength in the FBG for the three applied forces. As expected, the strain given by the FBG placed in the perpendicular direction of the tail boom is noticeably smaller than the ones provided by the FBG placed longitudinally.

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