FBG Thermal Response Analysis for Electro-Mechanical Components Monitoring in Aerospace Systems

Electromechanical components are widely used in aerospace systems and must meet strict reliability, safety, and environmental requirements. On the other hand, Fiber Bragg Grating (FBG) sensors are particularly advantageous to monitor specific physical parameters, like temperature or strain, due to their small size, low weight, high sensitivity, electrical passivity, and immunity to electromagnetic interference. The current study examines the performances of FBGs, enhancing their ability to read short-term thermal transients and comparing it to that of a conventional thermal probe (PT100). At first, instrumentation was placed in a climatic chamber and subjected to different thermal cycles. Specifically, an experimental set-up was developed to compare FBG's sensitivity under different fiber integration strategies. The different solutions implemented considered sensors independently from supports influence and when placed in simple example of packaging. In a second time, both environmental and punctual thermal transients were considered. The performances of the various solutions adopted were duly compared and supported by statistical analysis. Tests have shown that optical sensors have an extremely high sensitivity and a much shorter reaction time if compared to the PT100 probe. Moreover, it resulted that when FBG are integrated in other material, they are able to detect their support's temperature de facto in real time. Data collected by this work allow to consider strategic the use of FBG for thermal monitoring using a minimally invasive and extremely accurate technology.

Keywords: Aerospace, Fiber Bragg Gratings, FBG, Onboard system, Optical fibers, Prognostics, Sensors network, Smart sensor, Temperature probe, Thermal measurements, Actuators, Electro-mechanics, Safety, Reliability.

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