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Flight Tests of Fiber-Optic Interferometric Strain Gauges for Load Monitoring of Aircraft Structures

  • Norbert Fürstenau
  • Douglas D. Janzen
  • Walter Schmidt

Abstract

A large number of fiber optic interferometric strain gauge concepts has been investigated during recent years (e.g. 1,2,3), however only little experience exists up to now with respect to aerospace applications under real world conditions4,5. In this paper we report inflight dynamic load monitoring of plates made from carbon fiber composites, which are screwed to the main wing spar of a Cessna C207A. Several flight tests have been performed with four different sensors since June 92. The fringe counting readout of passive quadrature demodulated double-polarization Michelson interferometers with balanced interferometer arms (OSG)3 is compared to the strain indicated by conventional resistive strain gauges (ESG). Of particular interest is the response of the interferometric sensor to the quasistatic maneuver-dependent load variations given strong simultaneous structural vibrations due to engine and aerodynamic effects.

Keywords

Flight Test Carbon Fiber Composite CFRP Plate Flight Test Data Quadrature Demodulation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
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    N. Fürstenau, W. Schmidt, H.-C. Goetting, Simultaneous interferometric and Polarimetric strain measurements on composites using a fiber-optic strain gauge, Appl. Opt. 31:2987(1992)CrossRefGoogle Scholar
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    N. Fürstenau, D.D. Janzen, W. Schmidt, In-flight strain measurements on structurally integrated composite plates using fiber-optic interferometric strain gauges, Smart Mater. Struc. 2:2987 (1993)CrossRefGoogle Scholar
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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • Norbert Fürstenau
    • 1
  • Douglas D. Janzen
    • 1
  • Walter Schmidt
    • 1
  1. 1.Institute for Right GuidanceGerman Aerospace Research Establishment (DLR)BraunschweigGermany

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