Elastoviscoplastic rheology and aging in a simplified soft glassy constitutive model

Fielding, Suzanne M.

Abstract

Yield stress fluids display a rich rheological phenomenology. Beyond the defining existence of a yield stress in the steady state flow curve, this includes, in many materials, rather flat viscoelastic spectra over many decades of frequency in small amplitude oscillatory shear; slow stress relaxation following the sudden imposition of a small shear strain; stress overshoot in shear startup; logarithmic or sublinear power-law creep following the imposition of a shear stress below the yield stress; creep followed by yielding after the imposition of a shear stress above the yield stress; richly featured Lissajous–Bowditch curves in large-amplitude oscillatory shear; a Bauschinger effect, in which a material’s effective yield strain is lowered under straining in one direction, following a preceding strain in the opposite direction; hysteresis in up-down shear rate sweeps; and (in some materials) thixotropy and/or rheological aging. A key challenge is to develop a constitutive model that contains enough underlying mesoscopic physics to have meaningful predictive power for the full gamut of rheological behavior just described, with only a small number of model parameters, yet is simple enough for use in computational fluid dynamics to predict flows in complicated geometries, or complicated flows that arise due to spontaneous symmetry breaking instabilities even in simple geometries. Here, we introduce such a model, motivated by the widely used soft glassy rheology model, and show that it captures all the above rheological features.

Citation

Fielding, S. M. (2020). Elastoviscoplastic rheology and aging in a simplified soft glassy constitutive model. Journal of Rheology, 64(3), Article 723. https://doi.org/10.1122/1.5140465

• Journal Article Type: Article
• Acceptance Date: Feb 29, 2020
• Online Publication Date: Apr 9, 2020
• Publication Date: May 31, 2020
• Deposit Date: Apr 29, 2020
• Publicly Available Date: Apr 9, 2021
• Journal: Journal of Rheology
• Print ISSN: 0148-6055
• Electronic ISSN: 1520-8516
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 64
• Issue: 3
• Article Number: 723
• DOI: https://doi.org/10.1122/1.5140465
• Public URL: https://durham-repository.worktribe.com/output/1271923