Fracture and relaxation in dense cornstarch suspensions
Author(s)
Lilin, Paul
Elkhoury, Jean E
Peters, Ivo R
Bischofberger, Irmgard
Date Issued
December 21, 2023
Journal
PNAS Nexus
Publisher
Oxford University Press
Citation
Paul Lilin, Jean E Elkhoury, Ivo R Peters, Irmgard Bischofberger, Fracture and relaxation in dense cornstarch suspensions, PNAS Nexus, Volume 3, Issue 1, January 2024, pgad451.
Version
Final published version
Abstract
Dense suspensions exhibit the remarkable ability to switch dynamically and reversibly from a fluid-like to a solid-like, shear-jammed (SJ) state. Here, we show how this transition has important implications for the propensity for forming fractures. We inject air into bulk dense cornstarch suspensions and visualize the air invasion into the opaque material using time-resolved X-ray radiography. For suspensions with cornstarch mass fractions high enough to exhibit discontinuous shear thickening and shear jamming, we show that air injection leads to fractures in the material. For high mass fractions, these fractures grow quasistatically as rough cavities with fractured interfaces. For lower mass fractions, remarkably, the fractures can relax to smooth bubbles that then rise under buoyancy. We show that the onset of the relaxation occurs as the shear rate induced by the air cavity growth decreases below the critical shear rate denoting the onset of discontinuous shear thickening, which reveals a structural signature of the SJ state.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1093/pnasnexus/pgad451
