Hierarchical Multiscale Approach for Modeling the Deformation and Failure of Epoxy-Based Polymer Matrix Composites

Area of Science:

• Materials Science
• Computational Chemistry
• Polymer Science

Background:

• Polymer matrix composites (PMCs) are essential in various industries.
• Accurate modeling of their mechanical properties is crucial for design and performance.
• Traditional models often simplify the complex interface between matrix and reinforcement.

Purpose of the Study:

• To characterize the molecular structure and mechanical properties of the epoxy matrix near fiber interfaces in PMCs.
• To develop a more accurate computational model for PMC behavior.
• To compare the predictive capabilities of CG-MD-informed models versus conventional models.

Main Methods:

• Coarse-grained molecular dynamics (CG-MD) simulations were employed to analyze the epoxy matrix structure.
• Free-volume hole radius distribution was measured as a function of distance from the matrix-fiber interface.
• Correlations between mechanical properties, free volume, and cross-linking were established.
• Results were integrated into a finite element model (FEM) for upscaled analysis.

Main Results:

• Molecular structure analysis revealed variations in free-volume distribution near the interface.
• Established correlations between epoxy mechanical properties and free-volume characteristics.
• CG-MD-informed FEM predicted localized damage near the fiber-matrix interface.
• Conventional FEM overestimated PMC strength and predicted uniform damage evolution.

Conclusions:

• CG-MD simulations provide critical insights into the molecular-level behavior of the epoxy matrix.
• Upscaling CG-MD results into FEM leads to more accurate predictions of PMC mechanical response and damage.
• This approach highlights the importance of considering interfacial effects in composite modeling.