The weakly nonlinear response and nonaffine interpretation of the Johnson-Segalman/Gordon-Schowalter model

Nabil Ramlawi, N. Ashwin Bharadwaj, Randy H. Ewoldt

Research output: Contribution to journalArticlepeer-review

Abstract

We derive new analytical solutions for the nonaffine Johnson-Segalman/Gordon-Schowalter (JS/GS) constitutive equation with a general relaxation kernel in medium-amplitude oscillatory shear (MAOS) deformation. The results show time-strain separable (TSS) nonlinearity, therefore providing new physically meaningful interpretation to the heuristic TSS nonlinear parameter in MAOS [Martinetti and Ewoldt, Phys. Fluids 31, 021213 (2019)]. The upper-convected, lower-convected, and corotational Maxwell models are all subsets of the results presented here. The model assumes that the microscale elements causing stress in the material slip compared to the continuum deformation. We introduce a visualization of the nonaffine deformation field that acts on stress-generating elements to reinforce the physical interpretation of the JS/GS class of models. Finally, a case study is presented where previously published results, from fitting TSS models to MAOS data, can be reinterpreted based on the concept of nonaffine motion of the JS/GS framework.

Original languageEnglish (US)
Pages (from-to)1409-1424
Number of pages16
JournalJournal of Rheology
Volume64
Issue number6
DOIs
StatePublished - Nov 1 2020

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'The weakly nonlinear response and nonaffine interpretation of the Johnson-Segalman/Gordon-Schowalter model'. Together they form a unique fingerprint.

Cite this