3D modeling of dual wind-up extensional rheometers

Publication: Research - peer-reviewJournal article – Annual report year: 2010

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Fully three-dimensional numerical simulations of a dual wind-up drum rheometer of the Sentmanat Extensional Rheometer (SER; Sentmanat, 2004 [1]) or the Extensional Viscosity Fixture (EVF; Garritano and Berting, 2006 [2]) type have been performed. In the SER and EVF a strip of rectangular shape is attached onto two drums, followed by a rotation of both drums in opposite direction. The numerical modeling is based on integral constitutive equations of the K-BKZ type. Generally, to ensure a proper uni-axial extensional deformation in dual wind-up drum rheometers the simulations show that a very small initial width and initial thickness of the strip is required. In the SER it requires an initial sample width of less than 2.5 mm and a thickness of less than 0.25 mm. This is typically observed for elastomer model. The overall picture is though more diverse, as the possibility to perform ideal uni-axial extension is very dependent of the constitutive equation. Especially the weighting between the convected relative strain tensors in the K-BKZ model seems to control the deviation from ideal behavior. Consequently, for melts or entangled liquids a proper uni-axial flow will be kept for a much wider parameter range. In fact only the appearance of a ductile necking or a large initial thickness of the sample will create a significant deviation from ideal extension. These simulations were based on MSF constitutive model.
Original languageEnglish
JournalJournal of Non-Newtonian Fluid Mechanics
Issue number1-2
Pages (from-to)14-23
StatePublished - 2010
CitationsWeb of Science® Times Cited: 22


  • BKZ, Extension, Elongation, SER, EVF, Rheometer, Lagrangian, Finite element
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