Shear thickening properties of nano SiO2/PEG dispersion system under impact loading

Shear thickening Fluid (STF) has a wide application in the field of protection due to its unique shear curing properties. However, the influences of particle content, constraint conditions, impact velocity and shear thickening properties of STF remain unclear. Therefore, SiO2 and PEG400 with a particle size of 100 nm were used as dispersoids and dispersants in the paper. The free drop of steel rod with different lengths have been conducted under the same speed and free boundary conditions. The dynamic mechanical behavior of the STF with fixed constraints at different speeds have been developed by using the Split Hopkinson Pressure Bar (SHPB). The experiment of free fall shows that the energy absorption of STF can be divided into three stages, namely, the entry stage, the equilibrium stage, and the recovery stage. During the entry stage, STF absorbs the external energy, and the equilibrium stage lasts about 3–4 ms. However when the mass fraction of dispersed in STF is 36%, the maximum loading distance of 400 mm steel bar is 1.4 mm at recovery stage. The SHPB experiment shows that the duration of the first response of STF is 20–25μs, and the wave velocity of STF is about 592.49 m/s.