Research on distributed fiber optic monitoring and field reconstruction of temperatures for aerospace vehicle shells

Accurate real-time identification of the temperature distribution on the fuel tank shell is critical for ensuring the safe operation of launch vehicles. This study proposes a method for reconstructing the temperature distribution using distributed fiber optic sensing. A finite element model and numerical simulations were used to obtain the temperature response characteristics of the shell. A temperature gradient evaluation method based on information entropy was introduced, combined with Bayesian optimization to refine the fiber sensing path. Additionally, a mutual information-based approach was developed to remove redundant information within the sensing path, significantly reducing the number of sensors required. A universal kriging-based reconstruction method was employed to estimate the temperature distribution in unmeasured regions of the shell. An OFDR-based distributed fiber optic sensing system was designed for monitoring the temperature of cylindrical structures. The proposed method reduced the root mean square error of temperature reconstruction and achieved near-global equivalent temperature measurements. The findings provide a technical foundation for thermal load monitoring, management, and control of critical aerospace structures.