Heat transfer mechanism and thermal conductivity prediction in short carbon fiber reinforced polymer composites

• Analyzed the effects of uniform and non-uniform factors on the anisotropic thermal conductivity of SFRC . • Established a joint rapid analysis method of uniform unit cell and correction unit cell. • The joint rapid analysis method can accurately predict the anisotropic thermal conductivity range of SFRC . Carbon fiber is commonly used as a heat dissipation filler for composite materials in aerospace and electrical systems. Based on representative volume element (RVE) finite element simulation and mathematical analysis, the anisotropic thermal conductivity of short carbon fiber/polymer (SCF/polymer) composites under non-uniform factors was predicted and analyzed. A joint analysis method was proposed for uniform unit cell (UUC) model considering uniform factors and correction unit cell (CUC) model considering non-uniform factors. This article establishes a UUC model for SCF/polymer composites and investigates the effects of factors such as the thermal conductivity of the polymer matrix, the anisotropic thermal conductivity, aspect ratio, and deflection angle of SCF, and interfacial thermal resistance on the anisotropic thermal conductivity of the composite material. In order to study the influence of non-uniform factors, a CUC model of SCF/polymer composite materials was established, and the effects of position offset, angle deviation, and distribution ratio of SCF in different directions on the anisotropic thermal conductivity of composite materials were discussed. The results of the above non-uniform factors were analyzed, and the range of correction factors for three non-uniform factors was obtained. The accuracy of the joint analysis method of UUC and CUC in predicting the anisotropic thermal conductivity of SCF/polymer composites was verified by comparing experimental results.