Approaching representative volume element size in interpenetrating phase composites

Uniform representative volume element (RVE) size for the effective electrical conductivity of interpenetrating graphite/aluminum (C/Al) composites were investigated using computer models of these composites. Results indicate that the uniform RVE size in these composites is very large, and that one can not rely on commonly employed single estimate numerical results using current computer models. It was found that it is at present impossible to make rational numerical predictions for these composites based on a single microstructure of a size. It was observed that all the individual predictions lie within the two Hashin-Shtrikman bounds and the smallest simulation cells the largest and the lowest predicted values differ by a factor of about 15.