Comparison of electrical mixture rules for composites

摘要: Firstly the basic theoretical methods of calculating dielectric properties heterogeneous mixtures are discussed. These mean field and effective medium theories integral methods. Formulae presented for systems containing parallel oriented ellipsoids randomly ellipsoidal systems. Theoretical formulae divided into two sub-groups: symmetric equations statistical asymmetric matrix-inclusion type composites. In former case only relative amount components is important, in second phase inversion results a change properties. compared numerically using spherical spheroidal with sharply different (permittivity ratio 1 ∶ 100). effect studied as well. Percolation behaviour predicted by demonstrated Functional shapes relation to differences. Finally, experimental data results, advantages drawbacks various For simplest formula yields somewhat worse values than or equations. The Looyenga equation does not work very well if permittivity difference high. nonspherical fit better general, even works satisfactorily. shape independence theory conflict data.