Numerical methods to predict composite material properties have emerged as an alternative to analytical techniques, such as the Mori-Tanaka Method. In principal, these methods are of higher fidelity than traditional analytical methods, accounting for complex filler/microstructure geometries and capable of predicting nonlinear behavior. In this study, the finite element method was used to analyze a periodic, three-dimensional representative volume element (RVE) for variety of filler geometries. Periodic boundary conditions were imposed on the RVE and two different methods for bridging micro- and macroscopic length scales are tested; mean field homogenization and asymptotic expansion homogenization. The computed moduli were compared with experimental results and Mori-Tanaka predictions. The incorporation of an interfacial layer into the finite element model allows for a closer agreement with experimental results.