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dc.contributor.authorPatel, MJen
dc.contributor.authorBlackburn, Sen
dc.contributor.authorWilson, Ianen
dc.date.accessioned2018-05-21T09:22:16Z
dc.date.available2018-05-21T09:22:16Z
dc.date.issued2018-01en
dc.identifier.issn0032-5910
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/275982
dc.description.abstractHighly filled suspensions (or pastes) present complex rheological behaviour and squeeze flow testing is used frequently for rheological characterisation. The extent to which liquid phase migration (LPM) occurs in such tests, and the influence of material extruded from between the plates, was investigated in experiments supported by detailed modelling based on soil mechanics approaches. Lubricated squeeze flow (LSF) tests were conducted on a model saturated ballotini paste prepared with a viscous Newtonian binder, at plate speeds spanning two decades. The tests were simulated using a two-dimensional (2 D) axisymmetric finite element model with adaptive remeshing to circumvent mesh distortion. The paste was modelled as a viscoplastic soil (Drucker-Prager) to capture both rate-dependent effects at high shear rates and LPM at low shear rates. Capillary pressure was applied at the evolving free surface and the plate surfaces were modelled as frictionless for simplicity. Reasonable agreement was obtained between the measured and predicted squeezing pressure profiles at the highest solids volume fraction tested (ϕs = 60%). Agreement was poor at the lowest ϕs (52.5%), which was due to this paste formulation behaving as a suspension/slurry without a distinct yield stress. For the first time, the predicted squeezing pressure was resolved into components using an energy analysis. The squeezing pressure was dominated by the work required to deform the paste in the gap. This result is specific to highly viscoplastic pastes and persisted to small plate separations when most of the sample lay outside the plates. Characterisation of the yield stress from the ‘shoulder’ in the squeezing pressure profile was reasonably accurate at h/h0 ≥ 96% (9% estimated error). LPM was neither observed nor predicted at the plate speeds tested, despite the favourable pore pressure driving force, due to the high binder viscosity and the zero dilation angle in the simulations. The flow field was characterised using a novel flow mode parameter derived from the shear rate tensor. The paste was predicted to undergo pure biaxial extension between the smooth plates, and for the first time was predicted to undergo pure uniaxial extension external to the plates and (briefly) pure shear at the boundary.
dc.publisherElsevier
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.subjectDrucker-Prager (DP)en
dc.subjectFinite element modelling (FEM)en
dc.subjectLiquid phase migration (LPM)en
dc.subjectLubricated squeeze flow (LSF)en
dc.subjectSoil mechanicsen
dc.subjectViscoplasticityen
dc.titleModelling of pastes as viscous soils - Lubricated squeeze flowen
dc.typeArticle
prism.endingPage268
prism.publicationDate2018en
prism.publicationNamePOWDER TECHNOLOGYen
prism.startingPage250
prism.volume323en
dc.identifier.doi10.17863/CAM.23260
dcterms.dateAccepted2017-09-26en
rioxxterms.versionofrecord10.1016/j.powtec.2017.09.052en
rioxxterms.versionVoR*
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en
rioxxterms.licenseref.startdate2018-01en
dc.contributor.orcidWilson, Ian [0000-0003-3950-9165]
dc.identifier.eissn1873-328X
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEPSRC (GR/S70340/01)
cam.orpheus.successThu Jan 30 12:59:46 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International