Effect of fiber transverse isotropy on effective thermal conductivity of metal matrix composites reinforced by randomly distributed fibers

The effective thermal conductivity of metal matrix composites (MMCs) reinforced by the randomly distributed transversely isotropic fibers is evaluated using the representative volume element (RVE) based finite element (FE) homogenization method. The modified random sequential absorption (RSA) algorithm is proposed to generate the periodic RVEs of MMCs and thus the periodic boundary conditions are introduced. The transversely isotropic thermal conductivity of fiber is considered and its numerical implementation in the FE analysis is detailed. The RVE based FE homogenization method to predict the effective thermal conductivity of MMCs reinforced by the randomly distributed fibers is verified by comparing against the experiment and the Hashin-Shtrikman bounds. The simulation results show that the effect of the transverse isotropy of fiber thermal conductivity on the effective thermal conductivity of MMCs reinforced by the randomly distributed fibers can be neglected owing to the large matrix/fiber thermal conductivity ratio. The effective thermal conductivity of MMCs reinforced by the randomly distributed fibers decreases with the increase of fiber volume fraction, while the effect of fiber aspect ratio on the effective thermal conductivity of MMCs reinforced by the randomly distributed fibers is not significant.