Effective moduli of two-layered spherical inclusions reinforced composites

A model is proposed to evaluate the effective moduli of a composite reinforced by two-layered spherical inclusions. This model is based on the localization problem of a two-layered spherical inclusion embedded in an infinite matrix. The interactions of the reinforced phases are taken into account by using the average matrix stress concept. When the external layer vanishes, the proposed model reduces to the classical Mori-Tanaka's model for spherical inclusions. Theoretical results for the composite of polyester matrix filled by hollow glass spheres and voids show excellent agreement with experimental results.