DEFORMABILITY OF A FLAX REINFORCEMENT FOR COMPOSITE MATERIALS

In this work, the deformability of a flax fabric adopted as composite reinforcement is experimentally investigated. The fabric (commercialized as FLAXPLY UD 180 by LINEO) is a quasi-unidirectional woven fabric with thin weft yarns connecting thick slightly twisted warp using satin weave interlacing pattern. The study is dedicated to the understanding and measurement of the main deformation mechanisms occurring during forming processes. The deformation during extension is investigated under uniaxial and biaxial loading in the in-plane tow directions (i.e. warp and weft). Particular attention is dedicated to the behavior during shear loading because this is considered the primary deformation mechanism in the reinforcement forming. Uniaxial bias extension and picture frame tests are adopted to measure the shear deformation. The tests are assisted by digital image correlation (DIC) technique to have a continuous measurement of the local deformation in the fabric plane during loading.