Paper Number
PO67 

Session
Poster Session

Title
Anticipating edge fracture

Presentation Date and Time
October 12, 2022 (Wednesday) 6:30

Track / Room
Poster Session / Riverwalk A

Authors (Click on name to view author profile)

  1. Marsh, Maxwell C. (University of Illinois at Urbana-Champaign, Mechanical Science and Engineering)
  2. Gergely, Ryan C. (General Motors Company, Research and Development)
  3. Ewoldt, Randy H. (University of Illinois at Urbana-Champaign, Mechanical Science and Engineering)

Author and Affiliation Lines (in printed abstract book)
Maxwell C. Marsh1, Ryan C. Gergely2 and Randy H. Ewoldt1
1Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; 2Research and Development, General Motors Company, Warren, MI 48088

Speaker / Presenter 
Marsh, Maxwell C.

Keywords
experimental methods; theoretical methods; flow-induced instabilities; polymer melts; suspensions

Text of Abstract
Free surface edge fracture truncates the range of rotational rheometers, causing false readings if undiagnosed. Here we derive “limit line” equations to anticipate edge fracture at a critical strain rate or strain, which helps to avoid bad data in steady shear flow, large-amplitude oscillatory shear (LAOS), and start-up shear, even when direct measurements of N2 or N1 are not available. The proposed limit line equations are tested with experimental measurements and nonlinear viscoelastic constitutive models to understand their accuracy. The equations derived here add to the growing list of non-ideal effects in rheometry that can be co-plotted as limit lines directly on material function measurements.