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Insights into complex rheological behaviour of carbon fibre/PEEK from a novel numerical methodology incorporating fibre friction and melt viscosity

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Show simple item record Deignan, Anne Figiel, Lukasz McCarthy, Michael A. 2018-03-12T14:35:59Z 2018
dc.description peer-reviewed en_US
dc.description.abstract A recent rheological study of carbon-fibre-reinforced PEEK (CF/PEEK) demonstrated highly complex behaviour, involving phenomenological differences at low and high strain rates. To explain the behaviour, it was hypothesised that CF/PEEK responds as a yield-stress fluid at low strain rates, with boundary-lubricated, fibre-fibre friction determining the viscosity, and as a viscous fluid at high strain rates, with polymer melt viscosity dominating the response. In this paper, a novel finite-element methodology, incorporating fibre friction and melt viscosity in the same model, is employed to study this hypothesis. Two-fibre models investigate how fibre friction and melt viscosity combine to produce an overall composite viscosity. Representative-volume-element (RVE) models examine multi-fibre/melt response, and demonstrate that inclusion of fibre friction produces the observed yield-stress behaviour at low strain rates, and viscous behaviour at high strain rates. Another phenomenon which affects rheological measurements of such composites is shear banding in the sample, which occurs in the yield-stress regime. This effect is demonstrated in the models, and analysis of load transfer between fibres and melt explains how it arises, and how it leads to diminished values of measured viscosity. The results pave the way for improved process models for high-throughput manufacturing processes such as Automated Tape Placement. en_US
dc.language.iso eng en_US
dc.publisher Elsevier en_US
dc.relation.ispartofseries Composite Structures;189, pp. 614-626
dc.rights This is the author’s version of a work that was accepted for publication in Composite Structures. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Composite Structures, 2018,m 189, pp. 614-626, en_US
dc.subject carbon fibres en_US
dc.subject thermoplastic resin en_US
dc.subject viscosity en_US
dc.subject Finite Element Analysis (FEA) en_US
dc.title Insights into complex rheological behaviour of carbon fibre/PEEK from a novel numerical methodology incorporating fibre friction and melt viscosity en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.identifier.doi 10.1016/j.compstruct.2018.01.084
dc.contributor.sponsor IRC en_US 2020-02-01
dc.embargo.terms 2020-02-01 en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US

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