2021/08/16 by Omer Sedes, Sedes, Omer, Bulbul Chakraborty +5 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Granular flow and fluidized beds #Material Dynamics and Properties #Soft Condensed Matter (cond-mat.soft) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.2108.07261
openalex publication_date 2021/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Shear thickening of suspensions is studied by discrete-particle simulation, accounting for hydrodynamic, repulsive, and contact forces. The contact forces, including friction, are activated when the imposed shear stress σ is able to overcome the repulsive force. The simulation method captures strong continuous and discontinuous shear thickening (CST and DST) in the range of solid volume fraction 0.54 ≤ ϕ≤ 0.56 studied here. This work presents characteristics of the contact force network developed in the suspension under shear. The number of frictional contacts per particle Z is shown to have a one-to-one relationship with the suspension stress, and the conditions for simple percolation of frictional contacts are found to deviate strongly from those of a random network model. The stress is shown to have important correlations with topological invariant metrics of the contact network known as k-cores; the k-cores are maximal subgraphs (`clusters') in which all member particles have k or more frictional contacts to other members of the same subgraph. Only k≤ 3 is found in this work at solid volume fractions ϕ≤ 0.56. Distinct relationships between the suspension rheology and the k-cores are found. One is that the stress susceptibility, defined as ∂ σ/∂ γ where γ is the shear rate, is found to peak at the condition of onset of the 3-core, regardless of whether the system exhibits CST or DST. A second is that the stress per particle within cores of different k increases sharply with increase of k at the onset of DST; in CST, the difference is mild.