In-orbit thermal deformation monitoring for composite laminated structures of remote sensing satellites using temperature self-decoupling fiber optical system and inverse finite element method

The phased array radar antennas of microwave remote sensing satellites can experience thermal deformation at extreme space temperatures, leading to a negative impact on image quality. This paper proposes a method for monitoring thermal deformation using Fiber Bragg Grating (FBG) sensing and the inverse Finite Element Method (iFEM). This study analyzes how the layout of FBG sensors affects the accuracy of reconstruction. It aims to optimize the topology of the FBG sensor network. Additionally, a strain transfer coefficient correction (STCC) algorithm is proposed to reduce the effect of strain transfer inaccuracies on the reconstruction result measurements. A Carbon Fiber Reinforced Polymer (CFRP) laminate is used as the simulation object for the radar antenna structure, and an experimental system is set up to monitor thermal deformation. The experimental results demonstrate that the maximum root mean square error (RMSE) is 0.038 mm under the temperature variation condition from 30 °C to 110 °C, which represents 5.4% of the maximum thermal deformation. The results indicate that the monitoring method is highly accurate in measuring the thermal deformation of critical structures in remote sensing satellites while in orbit. This method also shows great potential for a wide range of applications.