Integrated MD-FEA approach to investigate the mechanical behavior of effective carbon fiber/epoxy nanocomposites

D Bedi and R Gopi and S Sharma and SK Tiwari, MECHANICS OF ADVANCED MATERIALS AND STRUCTURES (2025).

DOI: 10.1080/15376494.2025.2489668

This study presents an integrated MD-FEA approach to predict the bulk elastic properties of epoxy nanocomposites reinforced with effective carbon fiber. Molecular dynamics simulations were conducted using LAMMPS to determine the elastic properties of carbon nanotubes, graphene (Gr), the epoxy matrix, and carbon nanotube/Gr-reinforced epoxy nanocomposites considering AIREBO and polymer consistent force field for interactions between the C-C atoms and the nanocomposites, respectively. These nanoscale findings were incorporated into finite element simulations in ABAQUS 2022 to evaluate the bulk mechanical properties of composites across varying effective carbon fiber volume fractions using representative volume element ensuring realistic composite modeling. The results demonstrate that reinforcing epoxy with carbon nanotubes and graphene significantly enhances the tensile strength and elastic modulus of the nanocomposites. A reduction in elastic properties was observed with increasing carbon nanotube diameters, highlighting the superior reinforcing effect of smaller-diameter carbon nanotubes. The strain rate influenced mechanical properties significantly, and an optimal strain rate of 10<^>9/s was identified, balancing mechanical improvement and computational efficiency. The multiscale model effectively predicts the impact of reinforcement on composite properties, revealing an increase in longitudinal and transverse Young's moduli and shear modulus with higher effective carbon fiber volume fractions. However, a critical threshold at 3% effective carbon fiber volume fraction was identified, beyond which mechanical properties declined, likely due to dispersion challenges. This integrated molecular dynamics-finite element approach provides a comprehensive understanding of the mechanical behavior of effective carbon fiber/epoxy nanocomposites across scales, offering valuable insights for designing advanced materials with tailored properties.

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