Elucidating the G? overshoot in soft materials with a yield transition via a time-resolved experimental strain decomposition

Gavin J. Donley, Piyush K. Singh, Abhishek Shetty, Simon A. Rogers

Research output: Contribution to journalArticlepeer-review

Abstract

Materials that exhibit yielding behavior are used in many applications, from spreadable foods and cosmetics to direct write threedimensional printing inks and filled rubbers. Their key design feature is the ability to transition behaviorally from solid to fluid under sufficient load or deformation. Despite its widespread applications, little is known about the dynamics of yielding in real processes, as the nonequilibrium nature of the transition impedes understanding. We demonstrate an iteratively punctuated rheological protocol that combines strain-controlled oscillatory shear with stress-controlled recovery tests. This technique provides an experimental decomposition of recoverable and unrecoverable strains, allowing for solidlike and fluid-like contributions to a yield stress material's behavior to be separated in a time-resolved manner. Using this protocol, we investigate the overshoot in loss modulus seen in materials that yield. We show that this phenomenon is caused by the transition from primarily solid-like, viscoelastic dissipation in the linear regime to primarily fluid-like, plastic flow at larger amplitudes. We compare and contrast this with a viscoelastic liquidwith no yielding behavior, where the contribution to energy dissipation from viscous flow dominates over the entire range of amplitudes tested.

Original languageEnglish (US)
Pages (from-to)21945-21952
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number36
DOIs
StatePublished - Sep 8 2020

Keywords

  • Elastoviscoplastic materials
  • Oscillatory shearing
  • Payne effect
  • Recoverable strain
  • Yield stress

ASJC Scopus subject areas

  • General

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