Monte Carlo simulations of effective electrical conductivity in short-fiber composites

The transport properties of conductive fiber composites are strongly dependent on the interactions between the conductive contents and their overall distribution, which is associated with the percolation and conduction of the relevant fibrous network. In this study, the fibers are modeled as randomly distributed three-dimensional cylinders with each cylinder consisting of a nonconductive core covered by a permeable conductive layer. By discretizing the interconnected surfaces of individual fibers, a finite element method is applied to evaluate the equivalent electrical conductivity of the entire system. Monte Carlo simulations are performed to quantify the relationships between the conductivity and the following factors: 1 the volume fraction, 2 the solidity of fibers, 3 the thickness of the coating layer, 4 the fiber aspect ratio, and 5 the distribution of the fiber orientation angles. In comparison with the model consisting of solid fibers, it has been shown that the coated structure can attain much higher conductivity. The associated percolation properties are also estimated from the computed conductivity, and the results show good agreement with those reported in the literature. These findings can be used as guidance in designing the next generation of multiscale conductive composites. © 2008 American Institute of Physics. DOI: 10.1063/1.2828180