Smart Composites Manufacturing and Testing by Insertion of Fiber Bragg Gratings Sensors

The development of aerospace systems requires to consider the complex challenge of having a wide network of sensors capable of ensuring high performance even in hostile environments. Fiber Bragg Grating (FBG) optical sensors effectively meet this goal, providing immunity to electromagnetic interference, minimal invasiveness, sensitivity to various physical parameters and a high operating temperature range. In particular, the minimal cable size of optical fiber lets the integration of optical sensing directly during the part manufacturing phase. This innovative approach could ensure the development of smart components, capable of autonomously providing fundamental data for the development of control algorithms, diagnostics, and predictive maintenance. This article describes the procedure for the fabrication and thermal testing of a composite material specimen, where the FBG was directly positioned during the lamination phase. Once successfully prepared, the specimen was tested in a climatic chamber through repeated thermal cycles. The measurements proved excellent thermal sensitivity, with a well-linear calibration curve unaffected by the lamination process. Moreover, the experimental campaign allowed for the calculation of the thermal flux trend within the specimen through-out the thermal cycle. The study, therefore, enhanced the huge potential of this method, from real-time monitoring to be data source for Artificial Intelligence or Augmented Reality.