关键词: 太阳能电池阵, 碳纤维增强环氧树脂（CF/EP）, 曲线坐标, 固体传热, 弹性变形

Abstract: In this paper, carbon fiber reinforced epoxy (CF/EP) composite plates for solar arrays were prepared by molding technology, and the macrostructure and microstructure were characterized by optical and scanning electron microscopy. Based on the above characterization results, a three-dimensional geometric model of CF/EP composite plates was constructed and substituted into the subsequent heat transfer and mechanical numerical model for solution. Firstly, based on the multi-physics field coupling calculation software Comsol, the solid heat transfer numerical model of CF/EP composite plates was established to reveal the mechanism of the influence of carbon fibers′ anisotropy on the heat transfer behavior of the composite plates. Through the curve coordinate system conversion algorithm, the relevant geometric model was converted from the three-dimensional Cartesian coordinate system to a curve coordinate system which is more suitable to describe the axial/longitudinal properties of carbon fibers, and can simplify the calculation. The actual heat transfer behavior of CF/EP was simulated with the boundary conditions such as surficial heat source region and surface air convection area. A constant temperature area and a thermal insulation area were set to reduce the difficulty of the solution. The above mathematical models were further solved based on the finite element method. Based on the calculated temperature field diagram and the heat vector in CF/EP composite plates, it is found that heat was transmitted preferentially along the axial direction of carbon fibers during heating. However, the thermal conductivity of the fiber in the radial direction was low. The mechanism of carbon fibers in improving the thermal conductivity of CF/EP composite plates was thus revealed. 
Further, the CF/EP three-dimensional geometric model was substituted into the mechanical numerical model, and the axial stress-strain model of CF/EP was established based on the finite element calculation software Abaqus. The research shows that, in the uniaxial tensile test along the fiber axis, the stress concentration occurs preferentially at the bonding interface between the carbon fiber and the resin matrix. The stress-strain relationship of CF/EP composite plates is calculated. It is found that during the initial elastic deformation of CF/EP, the carbon fibers arranged along the direction parallel to the stress bear most of the stress. When the strain rate rises to 1%, the internal stress of the axial carbon fibers can reach 54.1MPa at most. It can be seen that the strengthening effect of carbon fiber reinforcement on the mechanical properties also presents obvious anisotropy. 
In conclusion, based on the three-dimensional geometric model of the actual CF/EP composite plate, the anisotropic heat transfer and elastic deformation behavior model of CF/EP was constructed by combining the physical properties of carbon fibers and epoxy resins. The finite element method was used to solve the above models. The strengthening mechanism of carbon fibers on the heat transfer and mechanical properties of the epoxy resin matrix was revealed. This work can serve as a positive theoretical significance for the subsequent production, preparation and performance optimization of high-performance CF/EP composites and other carbon fiber-reinforced composites.

Key words: solar array, CF/EP, curve coordinate, solid heat transfer, elastic deformation