End-to-End FE Based Homogenization of Woven Composites

Whereas prediction of elastic properties of woven is a standard in the industry, prediction of their non-linear behavior remains a challenge. Accurate prediction of the non-linear behavior is the key for a successful modeling of woven composites solicited by off-axis loading. Woven composites are represented by interlacing yarns impregnated by a resin matrix. Yarns are made of a resin matrix reinforced by continuous fibers. Homogenization of woven composites therefore requires two levels of homogenization, the one of the yarn and the one of the ply. Finite element (FE) based homogenization at the ply level can be combined with mean-field homogenization at the yarn to predict the mechanical behavior of a single ply. The main difficulty of this approach lies in the generation of representative volume element (RVE) of a single ply. An end-to-end FE based homogenization of woven composites was developed in Digimat®. The developed set of tools allows running finite element simulations on single ply woven RVE with the use of mean-field homogenization at the yarn level. Generated RVEs are meshed with voxels to avoid meshing troubles in resin rich pockets between yarns or close to yarn crossings. The local fiber orientation used in the yarn homogenization is function of the yarn curvature. A fully analytical framework based on mean-field homogenization has also been developed. The particularity of this framework is that it takes yarn curvature into account. The developed tools will be presented and the FE based and mean-field homogenization predictions of linear and non-linear properties will be compared to experimental measurements on plain weave and 5HS carbon epoxy woven composites.