Shear thickening materials flow curve

Shear thickening materials show an increase in viscosity with increasing shear strain rate. An idealized flow curve is presented in Fig. 6, and the viscosity as a function of shear strain rate is depicted in Fig. 7. The shear thinning region usually extends only over about one decade of shear rate (power law index n > 1) in contrast to shear thinning, which usually covers at least two or three decades. Also, in many cases, shear thickening is preceded by a short phase of shear thinning at low shear strain rates. ° ... 

In some cases the very act of deforming a material can cause rearrangement of its microstructure such that the resistance to flow increases with an increase of shear rate. In other words, the viscosity increases with appHed shear rate and the flow curve can be fitted with the power law. Equation (20.3), but in this case n> 1. The shear thickening regime extends over only about a decade of shear rate. In almost all cases of shear thickening, there is a region of shear thinning at low shear rates. 

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