Random Lattice Electrical Conductivity Calculations for a Graphite/Epoxy Ply of Finite Thickness

A single ply of unidirectional graphite/epoxy composite is modeled by both a two-dimensional Cartesian square and a close packed triangular lattice of fibers of infinite width and finite thickness. All fiber cross-sections are cir cular (of the same diameter) and those fibers with centers located at adjacent points on the lattice will contact at the midpoint. From these contacts con duction paths are formed across the latice. To generate randomness, the cir cular fiber cross-sections are removed at random from the lattice, leaving va cant sites of insulating matrix material, until a certain fiber fraction is reached. Lattice conductivities are calculated for both models at various fiber fractions and lattice thicknesses. Good agreement is obtained when the asymptotic conductivity versus thickness curves are compared with ex perimental data.