Equivalent-inclusion approach and effective medium approximations for conductivity of coated-inclusion composites

•Effective conductivity of matrix-based coated-inclusion composite.•Equivalent inclusion constructed from a dilute solution result.•Effective medium approximations compared with finite element results.

Effective medium approximations are developed to estimate the macroscopic conductivity of inhomogeneous materials with coated-inclusion inhomogeneities. The two-phase coated inclusions are substituted by equivalent one-phase inclusions, with the help of an analytical dilute solution result. Then the available effective medium estimates can be applied to the simpler equivalent homogeneous-inclusion composites to estimate the effective conductivity of original composites. Numerical finite element results for a number of periodic structures illustrate the efficiency of the approach.