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Published on: November 22, 2021
Subyield Dynamics in Yield-Stress Materials
Alice Woodbridge1, Kasra Amini2, Fredrik Lundell2
1The University of Manchester, Department of Physics and Astronomy and Manchester Centre for Nonlinear Dynamics, Oxford Road, Manchester M13 9PL, United Kingdom.
Physical Review Letters
|May 11, 2026
Summary
Yield-stress materials below their yield point exhibit nonlinear viscoelasticity, not flow. Experiments show bounded, periodic strain responses, challenging models that predict plastic flow or pure elasticity in this regime.
Area of Science:
- Rheology
- Materials Science
- Soft Matter Physics
Background:
- The mechanical response of yield-stress materials below the yield point is debated.
- Conflicting constitutive models exist: one allows plastic flow, another assumes viscoelasticity below yield.
Purpose of the Study:
- To investigate the subyield behavior of microgels and emulsions.
- To determine if these materials flow or exhibit elastic behavior below the yield point.
Main Methods:
- Parallel superposition rheometry was employed.
- Residual slip effects were carefully accounted for.
Main Results:
- Both microgel and emulsion samples showed bounded, periodic strain responses.
- Compelling evidence suggests no flow occurs in the studied subyield regime.
Conclusions:
- The subyield regime is characterized by nonlinear viscoelasticity.
- Improved constitutive relations are needed to capture subyield nonlinearities without equating yielding to nonlinearity.
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