Percolation study of orientated short-fiber composites by a continuum model

We present a percolation study of a two-dimensional crossbar networks and investigate the percolation behavior in fiber-reinforced composites. A modified model of sticks with a finite width is proposed for predicting percolation threshold of volume fraction of the fiber-reinforced composites. Based on the presented model and Monte Carlo simulations, the influences of fiber aspect ratio and orientation on the percolation behavior were investigated. It was found that the percolation threshold had a linear dependence with aspect ratio more than 40 in double-logarithmic plot. The percolation threshold had larger dependence on the orientation angle less than 30∘. In terms of a model considering the tunneling effect, furthermore, the composite system filled with carbon nanotubes predicted to obtain lower percolation threshold. For lower fiber aspect ratios, fiber ends strongly affected the connection of crossbar networks.