Energy absorption of reticulated foams filled with shear-thickening silica suspensions

The need for smarter and adaptive, energy absorption materials especially for human protection applications has fueled the interest in new and alternative energy absorbing composites. In this thesis a 'novel' energy absorbing fluid-composite that utilized a shear thickening fluid is developed. Shear-thickening fluids are a class of field responsive fluids that have the ability to transition from low viscosity to high viscosity under an imposed deformation field. Two different types of silica particles are used to create shear thickening fluids. The first are polydisperse and non spherical, with a median diameter of 1.7 ± 1.4 micrometer, while the second are monodisperse spherical particles of 0.3 ± 0.03 micrometer diameter. The particles are dispersed in ethylene glycol at volume fractions of up to [phi]=47% for the polydisperse sample and up to [phi]=60% for the monodisperse spheres. The behavior of the silica suspensions is studied under steady shear, small and large amplitude oscillatory shear flow and also in transient extensional flow. The viscosity of the polydisperse suspension is found to be much greater than the monodisperse one due to the difference in particles shape. Oscillatory experiments indicate that both the onset and magnitude of the shear thickening depends on the frequency and strain applied and show that rapid time-varying deformations result in maximum energy dissipation.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Bettin, Giorgia

Advisor dc:contributor.advisor

• Gareth H. McKinley.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33904

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33904