Generalized combining rules for predicting transport properties of composite materials

Abstract

A general relationship is presented to predict the effective transport properties (electrical conductivity, thermal conductivity, dielectric constants, magnetic permeability, and diffusion coefficients) of composite materials in terms of the properties and concentration of the components and the internal microstructure. Numerous existing relationships are obtained as special cases. Filler shapes ranging from platelet, particulate, and short-fiber, to continuous fiber are consolidated within the relationship. Particular emphasis is given to isotropic composites containing particulate fillers. Simplifications appropriate for metal-filled polymers are presented. An interpretation of structural parameters is proposed which accounts for sharp transitions associated with percolation mechanisms.