The Rules of Mixture on Physical Properties of Composite Materials with Network Structure

Abstract

Functionally Gradient Material (FGM) is, especially, focused as a new heat-resistant material because of its thermal stress relaxation ability. In the design of FGM, estimation methods of physical property distributions, i.e. rules of mixture on physical properties, are required, because FGM has different composition in each region.
In this paper, thermal conductivity, Young's modulus and thermal expansion coefficient of composite materials with dispersive and/or network structure are calculated by finite element method (FEM) analyses. The results of the analyses were formulated with the volume fraction and a newly proposed geometric parameter which is correlated with the connectivity between perticles in the network structure. Thermal conductivity predicted by this formula had a good agreement with experimental value of SiO₂/Fe composite materials.