Describing and prescribing the constitutive response of yield stress fluids using large amplitude oscillatory shear stress (LAOStress)
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McKinley_Describing and prescribing.pdf
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Author(s)
Dimitriou, Christopher J.
Ewoldt, Randy H.
McKinley, Gareth H.
Date Issued
October 2012
Journal
Journal of Rheology
Publisher
Society of Rheology
Citation
Dimitriou, Christopher J., Randy H. Ewoldt, and Gareth H. McKinley. “Describing and Prescribing the Constitutive Response of Yield Stress Fluids Using Large Amplitude Oscillatory Shear Stress (LAOStress).” Journal of Rheology 57.1 (2013): 27.
Version
Author's final manuscript
Abstract
Large amplitude oscillatory shear (LAOS) is used as a tool to probe the nonlinear rheological response of a model elasto-viscoplastic material (a Carbopol microgel). In contrast to most recent studies, these large amplitude measurements are carried out in a stress-controlled manner. We outline a descriptive framework of characterization measures for nonlinear rheology under stress-controlled LAOS, and this is contrasted experimentally to the strain-controlled framework that is more commonly used. We show that this stress-controlled methodology allows for a physically intuitive interpretation of the yielding behavior of elasto-viscoplastic materials. The insight gained into the material behavior through these nonlinear measures is then used to develop two constitutive models that prescribe the rheological response of the Carbopol microgel. We show that these two successively more sophisticated constitutive models, which are based on the idea of strain decomposition, capture in a compact manner the important features of the nonlinear rheology of the microgel. The second constitutive model, which incorporates the concept of kinematic hardening, embodies all of the essential behaviors exhibited by Carbopol. These include elasto-viscoplastic creep and time-dependent viscosity plateaus below a critical stress, a viscosity bifurcation at the critical stress, and Herschel–Bulkley flow behavior at large stresses.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1122/1.4754023
