Stress fluctuations and shear thickening in dense granular suspensions

Abstract

forces 27,28 . The second regime is at high stresses (τ τ c ), where almost all particles come into direct, frictional contacts, and the viscosity (and also the normal stresses) diverge at a volume fraction φ µ J < φ 0 J that depends on the interparticle friction coefficient µ. With increasing stress τ , the crossover between these two rate independent regimes results in the shear thickening behavior. Thus, a complete description of the dynamics of dense granular

Shear thickening in dense suspension: A master-curve and “roll” of friction

“…, Egres [11]), Latex [12], and Glass [13] particles in different solvents. Particle size here spans almost an order of magnitude.…”

“…7. Literature experimental data sets: Typical shear-thickening behavior observed across diverse experimental systems ranging from PMMA (James et al [8], D'Haene et al[9]), Silica (Royer et al[10], Egres[11]), Latex[12], and Glass[13] particles in different solvents. Particle size here spans almost an order of magnitude.…”

Stress-activated Constraints in Dense Suspension Rheology

“…In Fig. 2 we compare the shear thickening behavior across a series of suspension types and volume fractions: sterically stabilized poly(methyl methacrylate) (PMMA) particles in dioctyl phthalate [38], charge stabilized silica particles in aqueous glycerol [39] or PEG-200 [40], glass beads in poly(dimethylsiloxane) (PDMS) [41], and carboxylate-coated particles in aqueous solutions [12,28]. While the differences in particle size and solvent/surface chemistries do affect the onset stress σ on for shear thickening (see Table I), plotting the reduced viscosity η r , i.e., η normalized by the viscosity of the suspending liquid, as a function of σ scaled by σ on reveals remarkably similar behavior at each volume fraction, with only a few minor deviations.…”

Geometric Pressure Minimisation of a Theoretical Die for Ceramic Extrusion

“…This does however highlight one obvious drawback with this method -that it makes no prediction of how the die geometry has an effect on the final extruded material. In certain materials, the extrusion process can have a direct impact on the alignment of the microstructure [13,14,15,16,17,18] or, in more general cases, cause agglomerate breakdown of ceramic components and agglomeration of defects such as air bubbles [19,20]. The exact purpose that the internal holed structure has may depend on the type of material wanted for extrusion and therefore you easily consider any layout an acceptable pressure loss.…”