Carbon fiber-reinforced polymer (CFRP) composites are widely used in aviation thermal insulation layers due to their high strength-to-weight ratio and excellent high-temperature performance. However, challenges remain regarding their structural integrity and durability under extreme conditions. This study first employed finite element simulation to model the damage evolution of CFRP laminated plates under axial tensile loads and their thermal decomposition behavior in high-temperature environments, providing a theoretical reference. Subsequently, experimental research was conducted on CFRP laminated plates embedded with fiber Bragg grating (FBG) sensors. In the tensile tests, FBG sensors accurately monitored the entire process from elastic deformation to damage propagation and eventual failure. In the high-temperature tests, despite a 75% reduction in tensile strength, FBG sensors effectively monitored damage evolution. Conclusively, the results demonstrate that FBG sensors possess reliable monitoring capabilities under complex conditions, making them a promising solution for the long-term structural health monitoring of aviation thermal insulation materials and paving the way for future developments in this area.

Carbon fiber reinforced polymer (CFRP) composites are prone to developing localized material loss defects during long-term service, which can severely degrade their mechanical properties and structural reliability. To address this issue, this study proposes a multi-sensor synchronous monitoring method combining embedded fiber Bragg grating (FBG) sensors and surface-mounted electrical resistance strain gauges. First, finite element simulations based on the three-dimensional Hashin damage criterion were performed to simulate the damage initiation and propagation processes in CFRP laminates, revealing the complete damage evolution mechanism from initial defect formation to progressive failure. The simulations were also used to determine the optimal sensor placement strategy. Subsequently, tensile test specimens with prefabricated defects were prepared in accordance with ASTM D3039, and multi-sensor monitoring techniques were employed to capture multi-parameter, dynamic data throughout the damage evolution process. The experimental results indicate that embedded FBG sensors and surface-mounted strain gauges can effectively monitor localized material loss defects within composite laminate structures. Strain gauge measurements showed uniform strain distribution at all measuring points in intact specimens (with deviations less than 5%). In contrast, in defective specimens, strain values at measurement points near the notch edge were significantly higher than those in regions farther from the notch, indicating that the prefabricated defect disrupted fiber continuity and induced stress redistribution. The combined use of surface-mounted strain gauges and embedded FBG sensors was demonstrated to accurately and reliably track the damage evolution behavior of defective CFRP laminates.

The load/strain time–history experienced by aircraft structures during service is crucial original input data for structural life reliability design, life extension, and health monitoring management. Accurately and reliably measuring the strain time–history of aircraft structures and their corresponding loading states is key. Aiming to improve upon the shortcomings of traditional airborne strain measurement methods, this paper proposes a key strain airborne measurement method suitable for load-bearing structures based on the characteristics and requirements of a certain type of aircraft load-bearing structure. An airborne multi-channel synchronous sampling test and acquisition system is designed and integrated for airborne measurement and acquisition of key strains and corresponding loading states of load-bearing structures. The main factors affecting the output of aircraft structure strain airborne measurements are summarized. Based on this, an uncertainty evaluation model for the airborne strain testing system is established, and the uncertainty of the output strain is quantitatively given using multivariate fuzzy evaluation. The key strain time–history of the load-bearing structure is obtained through flight measurement data collection and processing, and the collected strain history is analyzed in combination with simultaneously collected flight parameters. The results show that the proposed airborne strain measurement method and the integrated airborne strain measurement and acquisition system can reliably measure and reproduce the real loading history of the structure, providing reliable data support for structural damage estimation and life prediction management. It also provides an effective and practical reference for strain measurement of other aircraft structures.

A three-dimensional load regression system based on fiber Bragg grating strain sensor is proposed to meet the load monitoring requirements of the main landing gear of an aircraft during take-off and landing. The FBG sensors, featuring a strain resolution of 1 με and a strain sensitivity of 1.18 pm/με, were selected to ensure precise strain acquisition. Through three-dimensional modeling and static simulation of the main landing gear, the strain response trend of the structure under this load state is obtained as a reference for sensor placement. On this basis, the sensor networking scheme is designed, and the ground static load of the main landing gear is calibrated. The strain–load regression matrix model for the measured main landing gear is constructed through the collected strain data, and the reliability of its prediction is verified. The results show that the system can effectively monitor the structural load, and the error between the back-calculated regression load and the applied load is within 4%.