Turbulence

Dilatant

Materials science

Shear (geology)

Shear velocity

Dynamical friction

Shear stress

Geology

Oceanography

Volume fraction

Physics

Condensed matter physics

Particle (ecology)

Composite material

Mechanics

Jamming

Physical Review Letters

Particle-based simulations of discontinuous shear thickening (DST) and shear jamming (SJ) suspensions are used to study the role of stress-activated constraints, with an emphasis on resistance to gear-like rolling. Rolling friction decreases the volume fraction required for DST and SJ, in quantitative agreement with real-life suspensions with adhesive surface chemistries and "rough" particle shapes. It sets a distinct structure of the frictional force network compared to only sliding friction, and from a dynamical perspective leads to an increase in the velocity correlation length, in part responsible for the increased viscosity. The physics of rolling friction is thus a key element in achieving a comprehensive understanding of strongly shear-thickening materials.

Shear Thickening and Jamming of Dense Suspensions: The “Roll” of Friction