Shear deformation and energy absorption analysis of flexible fabric in yarn pullout test

The friction level between yarns significantly affects the ballistic performance of flexible fabrics. In this study, single yarn pullout tests of Kevlar 49 plain weave fabric under different preloads and different yarn pullout rates were carried out. The in-plane shear deformation of the fabric was measured using a digital image correlation method to determine the global shear strain and shear modulus. In addition, based on the stick-slip phenomenon in the process of yarn pulling, a bilinear stress transfer model between yarns was developed. The energy absorption mechanism and interface shear stiffness were theoretically analyzed, and the yarn interface parameters were inversely obtained from the experimental data. The analytical results of the proposed stress transfer model are consistent with the experimental load-displacement curve.