TY - JOUR
T1 - Transition between solid and liquid state of yield-stress fluids under purely extensional deformations
AU - Varchanis, Stylianos
AU - Haward, Simon J.
AU - Hopkins, Cameron C.
AU - Syrakos, Alexandros
AU - Shen, Amy Q.
AU - Dimakopoulos, Yannis
AU - Tsamopoulos, John
N1 - Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/6/9
Y1 - 2020/6/9
N2 - We report experimental microfluidic measurements and theoretical modeling of elastoviscoplastic materials under steady, planar elongation. Employing a theory that allows the solid state to deform, we predict the yielding and flow dynamics of such complex materials in pure extensional flows. We find a significant deviation of the ratio of the elongational to the shear yield stress from the standard value predicted by ideal viscoplastic theory, which is attributed to the normal stresses that develop in the solid state prior to yielding. Our results show that the yield strain of the material governs the transition dynamics from the solid state to the liquid state. Finally, given the difficulties of quantifying the stress field in such materials under elongational flow conditions, we identify a simple scaling law that enables the determination of the elongational yield stress from experimentally measured velocity fields.
AB - We report experimental microfluidic measurements and theoretical modeling of elastoviscoplastic materials under steady, planar elongation. Employing a theory that allows the solid state to deform, we predict the yielding and flow dynamics of such complex materials in pure extensional flows. We find a significant deviation of the ratio of the elongational to the shear yield stress from the standard value predicted by ideal viscoplastic theory, which is attributed to the normal stresses that develop in the solid state prior to yielding. Our results show that the yield strain of the material governs the transition dynamics from the solid state to the liquid state. Finally, given the difficulties of quantifying the stress field in such materials under elongational flow conditions, we identify a simple scaling law that enables the determination of the elongational yield stress from experimentally measured velocity fields.
KW - Elastoviscoplastic materials
KW - Extensional flow
KW - Viscoplastic materials
KW - Yield strain
KW - Yield stress
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U2 - 10.1073/pnas.1922242117
DO - 10.1073/pnas.1922242117
M3 - Article
C2 - 32434919
AN - SCOPUS:85086169998
SN - 0027-8424
VL - 117
SP - 12611
EP - 12617
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 23
ER -