Viscoelastic experimental characterization of flax/epoxy composites

This work presents an experimental characterization of the mechanical behavior of unidirectional composites based on flax fibers and (bio-)epoxy resins. The study focuses on the viscoelastic and the pseudo-plastic response on the composites. Specimens have been produced through a LRTM process and tested in pure monotonic tension, and cyclic tension. The effect of the strain rate has been also investigated. This is found to have a strong influence due to the very high creep sensitivity of the material. Finally, intra-laminate variability of the mechanical properties has been also investigated. Results show that the mechanical properties of flax-based composites might show either good repeatability or high dispersion, based on the supplier quality of the rough materials. However, results show a defined transition point between E1 and E2, and a strain-based failure criterion. (C) 2018 The Authors. Published by Elsevier B.V.