New analysis and correlation between steady and oscillatory tests in fumed silica-based shear thickening fluids

Abstract

In recent years, the non-Newtonian behavior of shear thickening fluids (STFs) has motivated a sharp increase in the number of studies related to their use for engineering applications. For this reason, rheological characterization of STFs is crucial in order to develop and design new devices based on these novel smart fluids. Typically, different experiments have been carried out for the rheological characterization of STFs to prove their shear/strain thickening behavior. In order to find an empirical relationship between steady and oscillatory experiments, the modified Cox-Merz rule has been recently used to correlate the results with enormous controversy between authors due to the disparity in the correlations achieved. In this paper, we present an improvement in the correlation between the results obtained in steady and oscillatory tests in STFs using fumed silica-concentrated suspensions. The proposed method with the use of strain sweep oscillatory tests has improved the correlation in all STF regimes (pre-transition, transition, and post-transition) in comparison with the results obtained using the modified Cox-Merz rule, which uses oscillatory frequency sweep tests. This improvement has been experimentally validated using concentrated colloidal suspensions with different concentrations of fumed silica (from 12.5 wt % to 25 wt %).

Fumed Silica-Based Suspensions for Shear Thickening Applications: A Full-Scale Rheological Study

“…According to previous studies, the critical shear rate (shear rate at which shear thickening takes place) increases as the particle size decreases. 1,16,21,81 Brownian stress is inversely related to particle size. Hence, as the particle size decreases, increased Brownian forces induce greater repulsive forces between the dispersed particles and the critical shear rate shifts to a higher value.…”

“…Suspensions of silica nanoparticles in a dispersant liquid can form a stable sol, a weakly flocculated gel, and a strongly flocculated gel. − Nonflocculated suspensions of silica can transform into shear thickening fluids when the shear rate exceeds a certain threshold . Various parameters affect the shear thickening behavior of silica-based suspensions, such as surface characteristics and concentration of particles, surfactants, temperature, interaction forces, and suspending medium. ,− Although several studies have examined the rheological behavior of fumed silica suspensions, very few have explored the shear thickening response and underlying mechanisms.…”

Stab and yarn pull-out resistance of shear thickening fluids (STFs)/E-glass based on PEG modification and modeling yarn pull-out behavior with artificial intelligence

“…[6][7][8] Due to own the thickening phase, this fluid is mostly considered to boost the ballistic and low-velocity impact resistance of fabrics utilized in armor applications. [2][3][4][5] One of the most common failure 1 School of Computer and Information, Qiannan Normal University for Nationalities, Duyun, China modes in textile structures such as armors is stab [8][9][10] and ballistic damage. 11,12 Stab damages are categorized into two classifications: cut and puncture.…”

“…Moreover, over a critical shear rate by increasing the shear rate the viscosity increases (thickening phase) and achieves a peak viscosity value because of nanoparticle hydrocluster formation by nanoparticles. [2][3][4][5] STFs exhibit a unique potential for use in a wide range of applications from mechanical platforms and smart structures to effective protective fabrics. [6][7][8] Due to own the thickening phase, this fluid is mostly considered to boost the ballistic and low-velocity impact resistance of fabrics utilized in armor applications.…”

Nonlinear vibration model of sandwich beam with a shear thickening fluid core

“…Shear thickening fluid is a non-Newtonian fluid and often is a dense suspension of nanoscale particles dispersed in a polar medium (An et al, 2019). At a certain critical shear strain rate, due to the build-up of large hydro-clustering (Wagner and Brady, 2009) or the friction between particles (Mari et al, 2014), its viscosity and shear modulus will suddenly jump to a higher level, exhibiting reversible shear thickening behavior (Moron et al, 2019). This makes constitutive model of STF highly nonlinear (Galindo-Rosales et al, 2011).…”