Paper Number
PO31
Session
Poster Session
Title
Late-stage creep dynamics of colloidal gels prior to yield
Presentation Date and Time
October 12, 2022 (Wednesday) 6:30
Track / Room
Poster Session / Riverwalk A
Authors
- Cho, Jae Hyung (Massachusetts Institute of Technology, Mechanical Engineering)
- Bischofberger, Irmgard (MIT)
Author and Affiliation Lines
Jae Hyung Cho and Irmgard Bischofberger
Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
Speaker / Presenter
Cho, Jae Hyung
Keywords
colloids; gels
Text of Abstract
Colloidal gels under constant moderate stress can undergo prolonged solid-like creep deformations prior to macroscopic yield. We experimentally investigate tertiary creep, the final stage of deformation that precedes yielding, using two types of gels: a strain-softening and a strain-hardening gel. We find that the shear rate the leads up to yield exhibits a slower temporal increase for the strain-hardening gel than for the strain-softening gel. In addition, in-situ optical imaging reveals that for the strain-hardening gel, cracks nucleate throughout the sample well before the onset of tertiary creep, while for the strain-softening gel, no macroscopic cracks are observed until just before yielding. The difference in the tertiary creep dynamics between the two systems may be understood in terms of distinct evolutions of their local yield stress distributions as local plastic events proliferate.