Mohammad Kazem Hassanzadeh-Aghdam

In this study, a hierarchical micromechanics-finite element modeling framework is developed to predict the effective elastic constants and thermal expansion coefficients (TECs) of epoxy-based ternary composites reinforced with graphite fibers and montmorillonite (MMT) clay nanofillers. At the nanoscale, representative volume elements (RVEs) are constructed by randomly dispersing MMT platelets within the epoxy matrix to capture their thermomechanical response. The homogenized properties obtained from the nanoscale RVEs are subsequently employed as the matrix phase in microscale RVEs, where continuous graphite fibers are embedded in the MMT nanoclay-filled epoxy matrix. The present modeling approach is validated through comparison with established analytical models and data reported in the literature. Parametric investigations are conducted to evaluate the effects of nanoclay volume fraction and aspect ratio, interphase region properties, and graphite fiber content on the elastic moduli, Poisson’s ratios, and TECs of the composite system. Results reveal that the incorporation of MMT nanoclay improves the thermo-elastic properties of the fibrous epoxy composites specifically in the transverse direction. In general, the engineering constants of the graphite fiber-reinforced epoxy composites containing MMT nanoclay fillers can be tuned by the microstructural features.

In this study, a comprehensive finite element (FE) modeling framework is developed to predict the effective Young’s modulus, Poisson’s ratio, and coefficient of thermal expansion (CTE) of a multi-phase nanocomposite comprising MXene nanoplatelets, spherical SiO ₂ nanoparticles, and an epoxy matrix. Representative volume elements (RVEs) are constructed to explicitly capture the morphology, spatial distribution, and size of both nanofillers, while interphase regions surrounding the MXene and SiO ₂ are incorporated as distinct phases to account for the interaction between the polymer and nanofillers. The FE simulations are performed under thermo-mechanical loading to evaluate the sensitivity of the hybrid nanocomposite properties to the interphase region, nanofiller percentage, MXene aspect ratio, SiO ₂ diameter, and nanofiller non-uniform dispersion. The results demonstrate that at the same content of nanofillers, the introduction of SiO ₂ nanoparticles into the MXene/epoxy nanocomposite leads to a decrease in its effective CTE. Also, the formation of interphase can improve the effective Young’s modulus and CTE of the MXene/SiO ₂ /epoxy nanocomposites. The proposed modeling approach offers a predictive pathway for optimizing multifunctional nanocomposite designs and provides quantitative insights into the synergistic role of hybrid nanofillers in tailoring advanced polymer nanocomposites for thermal-mechanical applications.