Fiber optic bragg gratings for structural health monitoring system of composite aerospace structures: limitations and engineering solutions. Review

The article presents a critical review of the application of fiber-optic Bragg gratings (FBGs) in structural health monitoring (SHM) systems for aerospace structures made of polymer composite materials. The physical principles of FBG operation are discussed, and existing experience in their use as strain, temperature, and structural integrity sensors within embedded sensing systems is summarized. Particular attention is paid to the key engineering limitations that hinder the widespread adoption of this technology, including the cross-sensitivity to strain and temperature, the influence of optical fiber embedding on the microstructure and durability of composite materials, challenges associated with the formation of reliable fiber input/output interfaces, as well as limitations related to the multiplexing capability and scalability of sensor networks for large-scale aerospace structures. The main approaches to mitigating these issues are analyzed, including the use of paired and modified gratings, optimization of fiber embedding schemes, application of specialized interfaces, and advanced interrogation techniques. The review is based on recent domestic and international studies as well as practical implementation cases. It is shown that the effectiveness of FBG‑based SHM systems is governed not by the individual characteristics of the sensors, but by the integrated engineering design of the sensing network, taking into account technological and operational constraints.