Using an established simulation method [1] and motivated by recent findings of rapidly forming rigid structures in dense suspensions [2], we show that the number of contacts in the particle network increases with imposed shear stress but also fluctuates during flow. A brief overview of particle interactions and shear-thickening behavior is provided to contextualize the network evolution driving changes in rheology.
We then examine two-dimensional suspensions (monolayers), where minimally rigid structures emerge as the system approaches jamming at high stress. The onset of large rigid clusters displays critical behavior. Extensions to three dimensions and connections to prior work on critical scaling near shear thickening and jamming are also discussed.
Jeff Morris is Director of the Levich Institute and Professor of Chemical Engineering at the City College of New York (CUNY). His research focuses on the fluid mechanics and rheology of complex fluids, especially suspensions, exploring how hydrodynamic and frictional interactions influence flow behavior, shear thickening, and particle migration.
He is a Fellow of both the American Physical Society and the Society of Rheology, and has received major honors including the 2023 Bingham Medal, the 2022 Weissenberg Award, and the 2019 APS Stanley Corrsin Award. He is Vice-President of the Society of Rheology (President in 2026–2027) and Associate Editor of the Journal of Fluid Mechanics. Morris is also co-author of A Physical Introduction to Suspension Dynamics and a CNRS Fellow-Ambassador (2023–2026).