NUMERICAL ANALYSIS OF THE ORTHOTROPIC TRANSVERSE STRENGTH OF NCF REINFORCED COMPOSITES

A finite element model has been developed for strength predictions in the transverse plane of Non-crimp fabric (NCF) reinforced composites. The numerical model considers a simplified representative volume element (RVE) description of the composite. The RVE consists of two material phases – the impregnated fibre bundle and the surrounding matrix material. The model considers competing failure modes initiating either in the fibre bundle or the surrounding matrix material. Intrabundle failure initiation in the homogenized fibre bundle is predicted with Mohr-Coulomb criterion, whereas failure initiation in the surrounding matrix material is predicted with the Raghava yield criterion. The aim of this study is to analyse the influence of fibre bundle geometry imperfections and the competing failure modes on the orthotropic performance in the transverse plane for NCF composites.Failure envelopes for multi-axial loading are generated by a superposition technique, which is very fast but limited to a linear response. Consideration of bundle geometry imperfections allows for prediction of the low out-of-plane tensile strength of the NCF composite observed in experiments