Paper Number
PO35 My Program
Session
Poster Session
Title
Not all recoverable strain is elastic
Presentation Date and Time
October 22, 2025 (Wednesday) 6:30
Track / Room
Poster Session / Sweeney Ballroom E+F
Authors
- Lee, Jiye (University of Illinois Urbana-Champaign)
- Rogers, Simon A. (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Jiye Lee and Simon A. Rogers
Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801
Speaker / Presenter
Lee, Jiye
Keywords
experimental methods; additve manufacturing; biomaterials; future of rheology; gels; granular materials; non-Newtonian fluids; rheometry
Text of Abstract
The phenomenon of strain recovery is well established as relating to elastic behaviors: when a stress is abruptly removed from a deformed material, it will recoil by an amount referred to as the recoverable strain or the elastic strain. The amount of deformation that remains unrecovered a long time after stress has been removed is associated with plasticity and has also been called ‘the permanent set’. In every rheological protocol, some strain can be said to have been acquired recoverably and some will be acquired unrecoverably. The rheology of yield stress fluids is important in numerous industrial, environmental, and biomedical applications owing to their ability to act as a solid or a liquid, or deform recoverably or unrecoverably, depending on the stress. The common conception of yield stress fluid rheology is that no unrecoverable strain is acquired below the yield stress. Here we study the process of recovery in brittle yield stress fluids via the KDR model with brittility [PNAS 121, 22 (2024) e2401409121]. While previous studies have assumed that all the strain recovered in a zero-stress step is elastic, we show that the process of recovery can induce plasticity that means more strain is recovered than would be expected by elasticity alone. That is, we show that yield stress fluids can transiently deform plastically even when the stress is zero. This extra amount of strain that is recovered has implications for experimental studies using recovery rheology principles. It is also qualitatively consistent with Lockwood and Fielding’s recent study of the Soft Glassy Rheology model [J. Rheol. 69, 329–341 (2025)], showing that both continuum and mesoscopic models predict the same phenomenon.