MIT Libraries logoDSpace@MIT

MIT
View Item 
  • DSpace@MIT Home
  • MIT Libraries
  • MIT Theses
  • Undergraduate Theses
  • View Item
  • DSpace@MIT Home
  • MIT Libraries
  • MIT Theses
  • Undergraduate Theses
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Fracture of the interlayer junction of the shell from a deep-sea hydrothermal vent gastropod

Author(s)
Wheeler, Kevin (Kevin R.), S. B. Massachusetts Institute of Technology
Thumbnail
DownloadFull printable version (4.750Mb)
Other Contributors
Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.
Advisor
Christine Ortiz.
Terms of use
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. http://dspace.mit.edu/handle/1721.1/7582
Metadata
Show full item record
Abstract
There is considerable amount of interest in the hierarchical nanomechanical processes that contribute to property amplification of biomaterials. An investigation of these processes and the quantification of the mechanical properties and structure of a biomaterial multilayer is determined. The multilayer was composed of an inner, aragonite-like layer and a middle, compliant layer with a gradient layer between the two exhibiting a non-uniform composition and structure. It was found that the hardness of the middle, compliant layer was 0.186±0.007 GPa, while the inner, aragonite-like had a hardness of 2.1±0.22 GPa. The hardness was found to be 1.66±0.44 GPa within the gradient layer. The indentation toughness of the inner layer was found to be 0.307+0.097 MPa*m1/2 . It was also found that cracks propagated along the grain boundaries within the inner and gradient layers. Crack growth was thus driven by the separation of the grains. The formation of multiple cracks ahead of the crack tip suggested the formation of bands analogous to dilatation bands observed in nacre under certain stress-states. Thus, the mechanisms behind grain separation, the micro-architecture of the anisotropic aragonite grains and other constituents, and the gradual compositional change observed in the tougher gradient layer all acted as toughening mechanisms and contributed to overall property amplification of the shell.
Description
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.
 
Cataloged from PDF version of thesis.
 
Includes bibliographical references (p. 29).
 
Date issued
2008
URI
http://hdl.handle.net/1721.1/58274
Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Publisher
Massachusetts Institute of Technology
Keywords
Materials Science and Engineering.

Collections
  • Undergraduate Theses

Browse

All of DSpaceCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

My Account

Login

Statistics

OA StatisticsStatistics by CountryStatistics by Department
MIT Libraries
PrivacyPermissionsAccessibilityContact us
MIT
Content created by the MIT Libraries, CC BY-NC unless otherwise noted. Notify us about copyright concerns.