Composite Carbon-Epoxy Tubes for Space Structures: Ground Vacuum Radiant Experiments and Structural Behavior Analysis

The utilization of composite carbon-epoxy tubes for space structures, such as antennas and solar arrays, has attracted considerable attention in recent decades due to their high strength-to-weight ratio and multifunctional applications. Among complex space environmental factors, thermal effects induced by uneven solar irradiance could generate temperature stress, cause thermal behavior and affect the guidance and control of spacecraft structures. In this paper, a series of temperature experiments for the identification of material properties and ground vacuum radiant experiments for the determination of the structural behavior of a composite carbon-epoxy tube are carried out with respect to space environments. Moreover, numerical models on the basis of experimental observations are developed to investigate corresponding thermal and structural behavior. It is found that the specific heat and thermal conductivity of two typical specimens increase linearly with temperature rise and are dependent on carbon directions. For thermal and structural experiments, a significant temperature difference of 30°C exists between top and bottom surfaces resulting from different radiation and heat conduction. A temperature difference of 8.7°C is found in the thick direction on the bottom surface, which could result in noticeable shear deformation during the service period. Average strains on top and bottom surfaces are -1,526 and -1,310 μϵ, respectively. Furthermore, numerical temperatures on the top surface are in good agreement with experimental results, while those on the bottom surface are higher than experimental temperatures due to the radiant effects of the chamber and complex interactions between the tube and tracks. A further numerical analysis on the thermal and structural behavior of the supporting frame could provide guidance for designing future corresponding structures.