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Homogenizing the viscosity of shear-thinning fiber suspensions with an FFT-based computational method

Sterr, Benedikt ORCID iD icon 1; Wicht, Daniel 1; Hrymak, Andrew; Schneider, Matti 1; Böhlke, Thomas ORCID iD icon 1
1 Institut für Technische Mechanik (ITM), Karlsruher Institut für Technologie (KIT)

Abstract:

In this work, we investigate the fiber orientation dependent viscosity of fiber suspensions using a computational homogenization method. To improve computational prediction capabilities for the viscosity of fiber suspensions, we extend an existing, Fast Fourier Transform based computational approach for fiber suspensions with linear viscous, i.e., Newtonian, matrix behavior to nonlinear viscous matrix behavior. Specifically, a Cross-type shear-thinning rheology is assumed for the matrix fluid. We employ composite voxels to lower resolution requirements and find through resolution studies that the resolution error decreases for certain shear rates. Furthermore, we conduct a volume element study and find that the representative volume element sizes for engineering considerations in a specific Newtonian case and the investigated Cross-type case are highly similar. For shear rates of engineering process interest we visualize the effective suspension viscosity in three dimensions and study the effects of the fiber volume fraction and the imposed macroscopic shear rate tensor on the suspension viscosity. We find that the elongational viscosity and the degree of anisotropy of the suspension viscosity vary stronger with the shear rate for higher fiber volume fractions. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000162506
Veröffentlicht am 29.09.2023
Originalveröffentlichung
DOI: 10.1016/j.jnnfm.2023.105101
Scopus
Zitationen: 2
Web of Science
Zitationen: 2
Dimensions
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Technische Mechanik (ITM)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 11.2023
Sprache Englisch
Identifikator ISSN: 0377-0257
KITopen-ID: 1000162506
Erschienen in Journal of Non-Newtonian Fluid Mechanics
Verlag Elsevier
Band 321
Seiten Art.-Nr. 105101
Vorab online veröffentlicht am 28.07.2023
Nachgewiesen in Web of Science
Scopus
Dimensions
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