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Visualization of the Fragmentation of a Weak Granular Material During Compression

Sbarro, Carmin (2007) Visualization of the Fragmentation of a Weak Granular Material During Compression. Master's Thesis, University of Pittsburgh. (Unpublished)

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The purpose of this research was to visualize the crushing of a weak granular material during compression. In order to be able to see the individual particles of the sample with out the usage of sophisticated and expensive equipment, roasted chick peas were used to model granular material. The chick peas were chosen because of their size and availability. A series of uniaxial confined compression tests were run on the chick peas to check different aspects of the fragmentation. All the samples used in the tests were prepared the same way having the same initial height and mass. The samples also had uniform gradation. An initial test was run on the chick peas to an applied vertical load of 3 kN. This test was used to create a void ratio versus the logarithm of the stress curve. From the curve constructed from the results of the first test four applied vertical loads were chosen. These four applied vertical loads were used throughout the research. The first set of uniaxial confined compression tests were used to determine how many chick peas were broken during compression. The next set of uniaxial confined compression tests were used to run sieve analysis on each sample and to determine how the gradation of the sample changed as the applied vertical load increased. Another confined uniaxial compression test was run to a selected load to determine how the crushing occurred internally. Through out the research several pictures were taken with a digital camera to help illustrate the crushing inside and outside the samples. Pictures outside the samples were possible since the cylinders used for the compression tests were transparent. A fractal analysis was done using the results of the sieve analysis for each sample. Fractal fragmentation dimensions were calculated to determine the degree of crushing at each of the applied vertical loads. Another fractal analysis was done using a Seirpinski Gasket in order visualize the way the samples developed a fractal size distribution. Six level of the gasket were generated and used to model a sample fragmenting during compression.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairVallejo, Luis Evallejo@engr.pitt.eduVALLEJO
Committee MemberGarcia, Calixto Igarcia@engr.pitt.eduCIGARCIA
Committee MemberLin, Jeen-Shangjslin@engr.pitt.eduJSLIN
Date: 25 September 2007
Date Type: Completion
Defense Date: 4 June 2007
Approval Date: 25 September 2007
Submission Date: 30 July 2007
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Civil and Environmental Engineering
Degree: MSCE - Master of Science in Civil Engineering
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: equilateral; fractal; Seirpinski gasket; uniaxial
Other ID:, etd-07302007-084546
Date Deposited: 10 Nov 2011 19:55
Last Modified: 15 Nov 2016 13:47


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