Yulei Xu

Study of the knife stab and puncture-resistant performance for shear thickening fluid enhanced fabric

This work developed a shear thickening fluid enhanced fabrics and the influence of the shear thickening fluid types on the knife stab and puncture resistance performance were investigated. The rheological properties of the shear thickening fluids were tunable by varying both the dispersing particles (silica, polymethylmethacrylate and polystyrene-ethylacrylate) and the mediums (ethylene glycol, polyethylene glycol 200 and polyethylene glycol 600). The mechanical properties of the shear thickening fluid reinforced fabrics were evaluated by the knife and spike drop tower testing, respectively. The hardness of the particles was the dominant factor for the knife stab resistance, while the inter-yarn friction played as the critical role for improving the puncture resistance. In comparison to neat fabric, the knife stab and puncture resistance of the shear thickening fluid-fabrics exhibited significant enhancement, which can be proven by the results of yarn pull-out testing and optical microscope images investigation. The enhancing effect was systematically discussed and the improving mechanism was analyzed. Because the influencing factors for the knife stab resistance and puncture resistance were different, the enhancing effect of the dispersing particles and the mediums for the shear thickening fluid-fabrics should be also different.

Shear Thickening Fluids Based on Additives with Different Concentrations and Molecular Chain Lengths

Shear thickening fluids (STFs) based on additives with different concentrations and molecular chain lengths were investigated. STF samples were prepared with silica and additive dispersed in polyethylene glycol (PEG) 400, where three types of additives with different molecular chain lengths of PEG4000, PEG6000, and PEG10000 were used. For PEG10000, different concentrations, including 0, 1%, 3%, and 5%, were selected to study the influences of additive concentrations. Rheological properties of the samples were measured with a rheometer. The results show that the shear thickening effect was significantly enhanced with the increase of the concentration and the molecular chain length of additives. The mechanism of enhancement was quantitatively explained with the formation of large particles clusters.