Paper Number
NF18
Session
Non-Newtonian Fluid Mechanics & Flow Instabilities
Title
Transient dynamics of the yielding transition in soft materials
Presentation Date and Time
October 17, 2018 (Wednesday) 11:30
Track / Room
Track 7 / Plaza II
Authors
- Donley, Gavin J. (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)
- de Bruyn, John R. (University of Western Ontario, Physics and Astronomy)
- McKinley, Gareth H. (Massachusetts Institute of Technology)
- Rogers, Simon A. (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)
Author and Affiliation Lines
Gavin J. Donley1, John R. de Bruyn2, Gareth H. McKinley3, and Simon A. Rogers1
1Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; 2Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7, Canada; 3Massachusetts Institute of Technology, Cambridge, MA 02139
Speaker / Presenter
Rogers, Simon A.
Text of Abstract
A rigorously-defined metric that maps the transient yielding response of elastoviscoplastic materials is proposed and investigated. Motivated by linear viscoelastic theory for oscillatory deformations, the method utilizes the motion of an instantaneous phase angle between the stress and strain of the rheological response within deformation space to quantify the yielding transition. Principal component analysis demonstrates that this phase angle velocity is based on the natural description for a material response in deformation space. The responses of the Carreau model in its plastic-like state, and a Carbopol microgel are investigated as theoretical and experimental model yield stress fluids. Use of the phase angle velocity clearly identifies the yield transition as being gradual and distributed across the microstructural deformation mechanisms within the material. This approach provides a physically-motivated understanding of the processes occurring during yielding of elastoviscoplastic materials.