Abstract/Details

Contact forces and angles in disordered materials


2008 2008

Other formats: Order a copy

Abstract (summary)

Disordered materials, such as window glass, powders, gels, concentrated emulsions, differ tremendously in their microscopic detail, there is increasing evidence that they belong to a more general phenomenon known as jamming. The response of disordered materials to applied stresses is a particularly interesting but difficult problem with broad applications in many fields. Using confocal microscopy, we performed systematic and detailed measurements of inter-drop contact forces inside three-dimensional piles of frictionless liquid droplets. We found chain-like structures of contact forces called force chains and measured long-range correlations of the directions and magnitudes of large forces. These correlations arise from the tendency of two largest forces on a droplet to oppose one another. Furthermore, we found that piles whose height was comparable to the length of force chains exhibited greater strain hardening than did tall piles. Thus, we established a connection between the microscopic force network and the elastic response of meso- or macroscopic disordered materials. A statistical model that incorporates the force-balance constraint and that assumes random orientation of contacts, confirmed the tendency of two large forces on a grain to oppose each other, which leads to the formation of force chains in disordered materials. This model also provided direct insight into other issues, such as the role of friction, the effects of stress anisotropy, the difference between two-dimensional materials and three-dimensional materials. The numerical results obtained from the model are qualitatively consistent with earlier simulations and experiments.

Indexing (details)


Subject
Statistics;
Condensation;
Materials science
Classification
0463: Statistics
0611: Condensation
0794: Materials science
Identifier / keyword
Applied sciences, Pure sciences, Confocal microscopy, Disordered materials, Emulsions, Force chains, Granular materials, Nanoparticles, Statistics
Title
Contact forces and angles in disordered materials
Author
Zhou, Jing
Number of pages
188
Publication year
2008
Degree date
2008
School code
0118
Source
DAI-B 69/07, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549664048
Advisor
Dinsmore, Anthony D.
Committee member
Bhatia, Surita R.; Davidovitch, Benny; Menon, Narayanan
University/institution
University of Massachusetts Amherst
Department
Physics
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3315524
ProQuest document ID
304566821
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304566821
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.