The rheological performance of shear-thickening fluids based on carbon fiber and silica nanocomposite

Current available shear-thickening fluid (STFs) may suffer from issues such as unsatisfactory energy dissipation performance and unstable dynamic stability for practical engineering applications. This paper investigates the innovated compounded STFs which are fabricated by mixing needlelike carbon fiber powder (CFP) and silicon dioxide (SiO2) into polyethylene glycol (PEG) under proper synthesis conditions. The microstructure and rheological properties of the compounded STFs, namely, CFP-SiO2/PEG, are investigated. The interaction between CFP and SiO2 and the shear-induced microstructure are analyzed using scanning electron microscopy. Steady-state rheological tests reveal that compounded STFs with different mass ratios exhibit significant rheological behavior and shear-thickening effects. The peak viscosity is demonstrated to be increased from 51.59 (monodispersed STFs) to 574.74 Pa s (compounded STFs), and the critical shear rate decreased from 79.42 to 10.00 s−1 when the mass fraction of CFP is set at 0.2%. The peak viscosity of the compounded STFs is shown to be increased by 313.96% when the plate spacing is increased from 0.25 to 1.00 mm. The dynamic rheological analysis shows that the compounded STFs exhibit excellent energy dissipation capacity at different stages. More importantly, the modulus instability and shear-thinning problems of monodispersed STFs could be significantly improved. According to the results, the key performance index of the CFP/SiO2-PEG compounded STFs is demonstrated to be improved by ten times or even higher. This work presents a novel type of STFs with high energy dissipation capacity and high dynamic stability for the application of shear-thickening fluids composite in engineering practice.