Three-dimensional microscopic assessment of randomly distributed representative volume elements for high fiber volume fraction unidirectional composites

Generating realistic non-uniformly distributed three-dimensional representative volume element (RVE) for modeling the response of high fiber volume fraction composites is challenging. A novel rapid approach employing a random event-driven molecular dynamics simulation (EDMD) was proposed in this study for this purpose. Distributions of continuous unidirectional fibers in the RVEs were assessed using two approaches, namely Voronoi tessellations and radial distribution functions. The developed method was highly efficient in generating RVEs with realistic fiber dispersions. Furthermore, applying the corresponding periodic boundary conditions (PBCs) for finite element modeling is also arduous. A technique was developed within the commercial finite element software ABAQUS to rapidly produce required matching mesh patterns on opposite surfaces of the RVE, and to apply the corresponding PBCs using custom scripts. By coupling the EDMD approach and custom scripts within ABAQUS to rapidly generate and mesh RVEs with high fiber volume fractions, evaluation of the RVE response was greatly simplified. In-and out-of-plane elastic properties of unidirectional glass/epoxy composite in a range of 10-80% fiber volume fractions were determined and compared with analytical models, and available experimental data, with good correlation.