The use of informed isotropic constitutive equation to simulate anisotropic rheological behaviors in fiber suspensions
| Autor: | Anthony J. Favaloro, Huan-Chang Tseng |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
010304 chemical physics Mechanical Engineering Isotropy Constitutive equation Mechanics Condensed Matter Physics 01 natural sciences Non-Newtonian fluid Physics::Fluid Dynamics Viscosity Flow (mathematics) Mechanics of Materials 0103 physical sciences Trouton's ratio Newtonian fluid General Materials Science 010306 general physics Shear flow |
| Zdroj: | Journal of Rheology. 63:263-274 |
| ISSN: | 1520-8516 0148-6055 |
| DOI: | 10.1122/1.5064727 |
| Popis: | Over the past three decades, the classic Lipscomb constitutive equation of fiber suspensions in the Newtonian fluids has often been used to discuss the fundamental effects of fiber orientation on flow fields. However, the numerical methods of the Lipscomb flow-fiber coupling employed to simulate anisotropic flows have always been unsatisfactory since convergent results have not been easily obtained, especially in industrial applications for high fiber concentrations. To derive a new informed isotropic (IISO) constitutive equation as an alternative Lipscomb form, particularly introduced with the strain-rate dependent parameter of the Trouton ratio, is a significant requirement. For the fiber-filled polymer melts, the IISO constitutive equation was used herein to predict the rheological behaviors from simple flow to complex flow, including an overshoot of the transient viscosity in shear flow and a dramatic change of the corner vortex in axi-contraction flow. For the practical injection molding simulation consisting of hybrid shear/extension flows, a peculiar filling pattern and a broader core orientation distribution were investigated, and experimental validation was realized.Over the past three decades, the classic Lipscomb constitutive equation of fiber suspensions in the Newtonian fluids has often been used to discuss the fundamental effects of fiber orientation on flow fields. However, the numerical methods of the Lipscomb flow-fiber coupling employed to simulate anisotropic flows have always been unsatisfactory since convergent results have not been easily obtained, especially in industrial applications for high fiber concentrations. To derive a new informed isotropic (IISO) constitutive equation as an alternative Lipscomb form, particularly introduced with the strain-rate dependent parameter of the Trouton ratio, is a significant requirement. For the fiber-filled polymer melts, the IISO constitutive equation was used herein to predict the rheological behaviors from simple flow to complex flow, including an overshoot of the transient viscosity in shear flow and a dramatic change of the corner vortex in axi-contraction flow. For the practical injection molding simulation c... |
| Databáze: | OpenAIRE |
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