Experimental Study on Yarn Pullout Test of STF Modified Fabric

Shear thickening fluid (STF) solution with SiO2 as dispersing phase and ethylene glycol as dispersing medium was prepared by ball milling, Kevlar49 plain woven fabrics impregnated with SFT were prepared. The impact resistance and shear deformation of the STF modified fabrics were studied by single-yarn pull-out tests and digital image correlation (DIC). The experimental results show that a dynamic slippage of yarns makes the STF attached to the yarn surface appear shear thickening effect, so the sliding friction between the yarn is higher than the static friction due to the increased viscosity. Therefore, the bigger pull-out force of the STF-fabrics increases the energy absorption capacity of the fabrics. The DIC results show that the maximum shearing angle and the residual shearing angle of the STF modified fabrics are larger than those of the pure fabrics, indicating that the STF will increase the friction between the yarns without affecting the fabric flexibility. (paper)