Optimal Molecular Dynamics System Size for Increased Precision and Efficiency for Epoxy Materials

Abstract

Molecular dynamics (MD) simulation is an important tool for predicting thermo-mechanical properties of polymer resins at the nanometer length scale, which is particularly important for efficient computationally driven design of advanced composite materials and structures. Because of the statistical nature of modeling amorphous materials on the nanometer length scale, multiple MD models (replicates) are typically built and simulated for statistical sampling of predicted properties. Larger replicates generally provide higher precision in the predictions but result in higher simulation times. Unfortunately, there is insufficient information in the literature to establish guidelines between MD model size and the resulting precision in predicted thermo-mechanical properties. The objective of this study was to determine the optimal MD model size of epoxy resin to balance efficiency and precision. The results show that an MD model size of 15,000 atoms provides for the fastest simulations without sacrificing precision in the prediction of mass density, elastic properties, strength, and thermal properties of epoxy. The results of this study are important for efficient computational process modeling and integrated computational materials engineering (ICME) for the design of next-generation composite materials for demanding applications.

LUNAR: Automated Input Generation and Analysis for Reactive LAMMPS Simulations

“…The models generated for both the DGEBF/DETDA system and the cyanate ester system were greater than 20,000 atoms; as Kashmari et al 73 have recently shown for an epoxy system, a minimum of 15,000 atoms was the ideal balance between computational efficiency and accuracy for thermomechanical property predictions. In total, six different packing methods were studied and are visualized in Figure 9 .…”