Deformability of 3D woven orthogonal non-crimp glass reinforcements

The deformability of a single layer E-glass non-crimp 3D orthogonal woven reinforcement is experimentally studied. The deformation during extension is investigated under biaxial loading in the in-plane tows directions (i.e. warp and weft). The biaxial tensile tests provide information on the initial nonlinear stiffening due to the low crimp in the tows. The effect of different strain rate ratios is also investigated. Particular attention is dedicated to the behavior during shear loading because this is considered the primary deformation mechanism in the reinforcement shaping. The mechanism occurs when the material is subjected to in-plane shear is studied by two different tests: bias and picture frame. The nonlinear response of the material from both tests is compared in term of macroscopic shear force vs. shear strain. The shear deformation is observed and measured at the macroscale, to have the initiation of wrinkling phenomenon, as well as at the unit cell level to study sliding and rotation of the tows. For these purposes, the tests are assisted by digital image correlation technique. Investigation at the unit cell level of the sheared geometry for different shear angle is performed by micro-CT observations. The obtained results represent an initial data set for the simulation of a forming process with such 3D reinforcement.