Bias-extension of woven composite fabrics

Woven-fabric reinforced composites have gained a significant attention from both industrial and academic fields, due to their high specific strength and stiffness as well as their supreme formability characteristics. In this work, the challenges in woven composites forming, from material variations, experimental material characterization methods to numerical modeling is reviewed and results on material shear behavior from bias-extension tests are presented. Three different types of fabrics (plain, balanced twill, and unbalanced twill weaves) were tested using various aspect ratios. From force-displacement curves, shear angles and normalized shear forces were theoretically determined and test data from different aspect ratios were compared with each other. Additionally, real-time shear angles were measured using the IcaSoft image correlation software developed at INSA-Lyon and compared with manually measured shear angles.