Back stress in modeling the response of PEEK and PC

Wenlong Li, George Gazonas, Eric N. Brown, Philip J. Rae, Mehrdad Negahban

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


With the development of new methods for the characterization of equilibrium stress through cyclic loading, it is now possible to follow the evolution of back stress during the nonlinear deformation of polymers. Experiments on PEEK and PC below the glass-transition temperature indicate a back stress that may evolve with plastic deformation, and which is substantially different from that seen during the response in the rubbery range. In particular, the back stress during the response of PC shows the characteristic post-yield softening, possibly indicating that the observed post-yield softening in the response comes from the back stress. This is not seen in PEEK, which also shows no substantial post-yield softening. The equilibrium stress plays a central role in modeling both the quasi-static and dynamic response of PEEK.

Original languageEnglish (US)
Title of host publicationChallenges in Mechanics of Time Dependent Materials- Proceedings of the 2016 Annual Conference on Experimental and Applied Mechanics
EditorsJevan Furmanski, H. Jerry Qi, Alex Arzoumanidis, Alireza Amirkhizi, Meredith Silberstein, Hongbing Lu, Bonnie Antoun
PublisherSpringer New York LLC
Number of pages6
ISBN (Print)9783319415420
StatePublished - 2017
EventAnnual Conference and Exposition on Experimental and Applied Mechanics, 2016 - Orlando, United States
Duration: Jun 6 2016Jun 9 2016

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652


OtherAnnual Conference and Exposition on Experimental and Applied Mechanics, 2016
Country/TerritoryUnited States


  • Digital image correlation
  • Equilibrium stress
  • Mechanical modeling
  • Plastic flow
  • Thermal expansion

ASJC Scopus subject areas

  • General Engineering
  • Computational Mechanics
  • Mechanical Engineering


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