2026-09-20T02:35:29Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1279242021-07-05T14:03:20Zcom_1721.1_7582com_1721.1_7581col_1721.1_131024
Irmgard Bischofberger.
Griese, Andrew Herman.
Massachusetts Institute of Technology. Department of Mechanical Engineering.
Massachusetts Institute of Technology. Department of Mechanical Engineering
2020-10-08T21:30:39Z
2020-10-08T21:30:39Z
2020
2020
https://hdl.handle.net/1721.1/127924
1197973764
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 16-17).
Dense suspensions of solid particles in Newtonian fluids exhibit a variety of non-Newtonian behaviors depending on the shear stress applied to the suspension and the particle mass fraction ([mathematical symbol]m). Suspensions at sufficiently high fm shear-thicken dramatically and eventually shear jam, showing behaviors typified by solids. But, little is known about how dense suspensions relax out of this stressed rheological state. To understand the relaxation behavior of a cornstarch/water dense suspension, samples are prepared at different fm, in the range that shows dramatic shear thickening, between 54.5% and 58.5% cornstarch. Each sample is formed into drops and kept in the stressed state through dynamic shearing using a B&K permanent magnet shaker, then allowed to relax. We show that dense suspensions relax with two distinct timescales. A short timescale that is independent of [mathematical symbol]m, denoting the settling of the drop onto the flat surface, and a longer timescale that is governed by the viscosity of the dense suspension and increases as [mathematical symbol]m increases above 55.75%. Our work provides an understanding of how a dense suspension relaxes out of a shear-thickened state.
by Andrew Herman Griese.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
17 pages
eng
Massachusetts Institute of Technology
MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided.
http://dspace.mit.edu/handle/1721.1/7582
Mechanical Engineering.
Relaxation behavior of dense suspensions
Thesis
application/pdf
2020-10-08T21:30:38Z
Publication
Bachelor
MechE
unknown
unknown
<Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="fdf8ea45-84ac-4bce-aa95-b6f9bd9d053a">
<Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type>
<Language>eng</Language>
<Title>Relaxation behavior of dense suspensions</Title>
<PublishedIn>
<Publication>
</Publication>
</PublishedIn>
<PublicationDate>2020</PublicationDate>
<Authors>
<Author>
<DisplayName>Griese, Andrew Herman.</DisplayName>
<Affiliation>
<OrgUnit>
</OrgUnit>
</Affiliation>
</Author>
</Authors>
<Editors>
</Editors>
<Publishers>
<Publisher>
<DisplayName>Massachusetts Institute of Technology</DisplayName>
<OrgUnit />
</Publisher>
</Publishers>
<License>http://dspace.mit.edu/handle/1721.1/7582</License>
<Keyword>Mechanical Engineering.</Keyword>
<Abstract>Dense suspensions of solid particles in Newtonian fluids exhibit a variety of non-Newtonian behaviors depending on the shear stress applied to the suspension and the particle mass fraction ([mathematical symbol]m). Suspensions at sufficiently high fm shear-thicken dramatically and eventually shear jam, showing behaviors typified by solids. But, little is known about how dense suspensions relax out of this stressed rheological state. To understand the relaxation behavior of a cornstarch/water dense suspension, samples are prepared at different fm, in the range that shows dramatic shear thickening, between 54.5% and 58.5% cornstarch. Each sample is formed into drops and kept in the stressed state through dynamic shearing using a B&K permanent magnet shaker, then allowed to relax. We show that dense suspensions relax with two distinct timescales. A short timescale that is independent of [mathematical symbol]m, denoting the settling of the drop onto the flat surface, and a longer timescale that is governed by the viscosity of the dense suspension and increases as [mathematical symbol]m increases above 55.75%. Our work provides an understanding of how a dense suspension relaxes out of a shear-thickened state.</Abstract>
<Access xmlns="http://purl.org/coar/access_right"
>
</Access>
</Publication>