An experimental investigation into strain distribution in 2D and 3D textile composites

Analytical models for textile materials are typically unit cell abstractions, which are incapable of assessing the effects of common fiber architecture defects. Experimental characterization of common defects is thought to be a way to assess the relative importance of a feature for inclusion in more complex analytical models. This paper addresses moiré interferometry experiments on idealized textile samples of decreasing abstraction (increasing reality of local features). Since interferometry measures displacements (strains) at a free surface, one must be careful to separate the effects due to textile architecture from those due to free-edge effects. Moiré interferometry techniques are shown to be ineffective for testing edges (surfaces which include interlaminar boundaries) of most real-world (non-idealized) textiles due to the inability to characterize the mechanical response due to local variations in microstructure. Thus, there is a need for fabricating samples of a very idealized nature.