Hong Wen, Xiao Peng, Luo Heng, Li Zhuan
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
Sci Rep. 2015 Oct 19;5:14927. doi: 10.1038/srep14927.
Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity.
采用浇注法制备了随机分布的碳纤维（CF）增强环氧树脂复合材料，并在8.2至12.4 GHz频率范围内对不同纤维含量和长度的CF复合材料的介电性能进行了研究。复合材料的复介电常数随纤维长度的增加而增大，这归因于去极化场的减小；随体积分数的增加而增大，这归因于极化的增强。基于雷诺兹 - 休理论提出了一个公式来计算CF复合材料的有效介电常数，并通过实验进行了验证。将所提出的公式进一步应用于推导CF的轴向介电常数，并分析纤维长度对轴向介电常数的影响。
