Automated generation of 3D orthogonal woven composites RVEs including yarn cross-section variations

This contribution presents an approach to generate unit-cell models of 3D orthogonal woven non-crimp fabric composites with the ability to incorporate cross-section variations in the weft and binder yarns. The approach starts from an initial loose-state configuration of the fiber-bundles, in which each fiber-bundle is represented by a single discretised line. The discretised lines are shaped in a step-wise generation process by geometrical operations. During the generation procedure, the surface weft yarns and the binder yarns are transformed into a boundary- or inner-line configuration, respectively, to account for their cross-section variation in subsequent steps. The fiber volume fraction and fiber direction to be used subsequently in simulations are modelled on cross-sections in a post-processing step. The shape of the surface weft yarn cross-section and binder yarn cross-sections and centerline for different binder contents, diameter and tensioning can be automatically accounted for. The geometrical models are then transformed into finite element models by an automated meshing procedure to investigate how the binder yarn, and cross-section variations in the surface weft and binder yarns alter the stiffness and damage initiation levels