Investigation of the conductivity of random networks

This work presents the results of numerical simulations concerning the electrical conductivity of two-component random resistor networks in d=3 as a model of composite media. Finite difference calculations have been carried out for several system sizes, conductance ratios and occupation numbers. Using an electric analogy an equation is developed empirically which fits the data at conductivity ratios of f=0.5–0.01. At f=0.001 enhanced deviations occur which are diminished by introducing an additional parameter in the epirical equation. The percolation threshold was determined to be about p*=0.25.