Physical modeling of composite materials utilizing 2D and 3D impedance networks

The ac and dc electrical properties of composite materials have been investigated by 2D and 3D impedance network simulations. The materials consist of an insulating matrix filled with moderately conducting particles. Different methods for distributing the conducting particles and separate types of contacts between them have been considered. Comparisons to measurements illustrate that the calculations reproduce the general characteristics of the experimental results. A distinctive percolation behavior is seen in the filler dependence of the dc conductivity and a universal relaxation is shown in the frequency dependence of the complex permittivity.