Mechanical behaviour analysis of the interface in single hemp yarn composites: DIC measurements and FEM calculations

The present work aims to investigate the local deformation mechanisms around a yarn in an eco-composite. Different hemp yarn orientations and two types of epoxy resin were tested. Full-field measurements were realised with the digital image correlation technique on specific single yarn composites, either on the face of the specimens, or on the edge. The tensile tests were performed under an optical microscope to give sufficient precision, and a numerical model was developed. The experimental results showed high heterogeneities in strain fields which increase with the applied stress level. The comparison with the underlying microstructure and the numerical model enabled us to study the influence of the yarn on the mechanical behaviour. The local constitutive behaviour of the different constituents of the specimens could be approached by these analyses. These results constitute a complete and original database on hemp/epoxy interface mechanical behaviour.