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UM E-Theses Collection (澳門大學電子學位論文庫)

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Title

Discrete element simulation of particle crushing in one-dimensional compression

English Abstract

In this study, discrete element method is used to investigate the behavior of onedimensional compression at high pressure. A multigenerational approach without using agglomerates is employed to model particle crushing. The breakage of a particle is decided by the octahedral shear stress within the particle due to the multiple contacts and a Weibull distribution of strengths. A discrete fragmentation multigenerational approach with volume compensation is applied as a spawning procedure. Compared to the approach without volume compensation in previous studies, it was found that the volume compensation allows better simulation of the compression behavior with particle crushing. Effects of different initial void ratio, particle size distribution of samples, and the influence of particle crushing on the coefficient of lateral earth pressure and the slope of the normal compression line were investigated. Evolution of distribution of normalized octahedral shear stress (ݍ ᇱ) and its influence on particle crushing were used to analyze macroscopic behavior of samples. At the initial state of loading, q' induced within each particle in the looser sample spreads out across a larger scope at the same vertical stress compared with denser samples. Mean q' inside the particles increases with the vertical stress linearly and looser samples has a higher mean q' at same vertical stress which can be explained by the higher co-ordination number. As particles inside samples begin to crush massively, VI statistical dispersion of q' distribution inside samples begin to increase for denser samples and achieve maximum at the failure stress and then statistical dispersion of q' distribution declines sharply when the vertical stress surpass the failure point for all samples.

Issue date

2017

Author

Liu, Si Kai

Faculty

Faculty of Science and Technology

Degree

M.Sc.

Subject

Discrete element method

Particles -- Mathematical models

Supervisor

Lok, Man Hoi

Files In This Item

Full-text (Intranet)

Location
1/F Zone C
Library URL
991005784559706306