碳纤维随机填充橡胶复合材料导热性能的数值模拟

Numerical Simulation of Thermal Conductivity of Rubber Composite with Randomly Distributed Carbon Fibers

运用随机顺序添加算法RSA(Random sequential addition method),基于均匀化理论建立了碳纤维填充橡胶复合材料代表体积单元RVE(Representative volume element)模型,利用有限元方法数值模拟研究了碳纤维对橡胶复合材料导热性能的影响。结果表明:在相同的填充分数下,碳纤维根数对复合材料导热性能的影响较小;合理安排碳纤维空间分布及纤维取向能有效提高复合材料的导热性能;复合材料的导热性随着碳纤维填料含量及长径比的增加而增大;与理论模型相比,基于碳纤维填料随机分布模型所得模拟结果与实验值较接近,尤其在高填充分数时与实验值吻合较好,可以更好地预测纤维填料填充复合材料的导热性能,对制备具有高填充分数的高导热复合材料具有一定的指导意义。

A representative volume element(RVE)that contained randomly distributed carbon fibers in rubber matrix was built by random sequential addition method(RSA)and the homogenization theory.Finite element method was used to investigate the thermal properties of the composite.The results showed that fiber numbers had little effect on the thermal conductivity at the same filling fraction.Carbon fibers could greatly improve the thermal conductivity of composite when their spatial distribution and orientation are reasonably arranged.Thermal conductivity of the compo site increased with the fiber filler content and aspect ratio.Compared to theoretical prediction,numerical results showed a good agreement with experimental results especially at high filling fraction.It is better to predict the thermal conductivity of carbon fiber filled composite using the random distribution model,which has guiding significance on the production of high thermal conductive composite.