Multiscale analysis of graphene-enhanced fiber-resin interfaces: effects of structural parameters on mechanical performance

The interfacial properties between carbon fiber (CF) and resin matrix play a crucial role in determining the mechanical performance of composite materials. While graphene modification is widely studied, there is still a need for a multiscale framework to analyze how the structural parameters govern interfacial mechanical properties and influence the overall mechanical performance of composite. In this study, a multiscale modeling framework integrating molecular dynamics (MD) and finite element modeling (FEM) was developed to link the nanoscale graphene structure to macroscale composite performance through cohesive zone modeling (CZM). Through MD simulations, the traction-separation (T-S) responses under tensile, shear, and mixed-mode failure were obtained. The simulation results reveal that the addition of graphene layers enhances interaction between fiber surface and resin matrix by increasing fiber surface area. However, excessive graphene height or density leads to reduced interfacial mechanical performance. Furthermore, a uniform graphene layer alignment significantly improves interfacial fracture performance. These atomic derived insights were subsequently incorporated into a cohesive zone model, enabling FEM to evaluate how structure parameters impact macroscale mechanical performance. The results show that the improved interfacial mechanical properties translate into improved composite strength by enhancing macroscale load transfer efficiency. This study provides a fundamental understanding of how fiber surface modifications influence composite performance and establishes a versatile computational framework that can be applied to optimize nanomaterial-based interfacial engineering in advanced composite materials.