Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisors: Suresh G. Advani, Dept. of Mechanical Engineering, and Eric D. Wetzel, Army Research Laboratory. Includes bibliographical references.

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Santamarina, J. Carlos; Committee Member: Bachus, Robert C.; Committee Member: Burns, Susan E.; Committee Member: Cartwright, Joseph A.; Committee Member: Goldsztein, Guillermo; Committee Member: Mayne, Paul W. Part of the SMARTech Electronic Thesis and Dissertation Collection.

We encounter granular materials on a daily basis. We walk up a gravel path or we eat our breakfast cereals. When handling granular materials on an industrial scale it is important to do so efficiently, to avoid unnecessary energy losses, wear and tear. To help designing efficient tools for handling these materials engineers uses numerical simulations. This project investigates the difference between the two main approaches to simulation of granular materials, the Smooth- and Non-smooth Discrete Element Methods by implementing the Smooth method into AgX dynamics were the Non-smooth method already is implemented, and then setup and execute a range of experiments to investigate their differences. The investigation shows both advantages and weaknesses for both methods. The result of simulations with smooth discrete element method are more consistent than with the nonsmooth discrete element method with respect to choice of time step and other parameters that can be chosen for the simulation. Smooth discrete element method have problems when it comes to extreme situations. The relative simulation time for system as large as treated by this project (more than1000) can not be shown to depend on the size of the system.

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This work examines the fundamental behaviour of granular materials in packed/moving beds under simplified blast furnace conditions. Such study has a significant impact on the development of new technology such as pulverized coal injection and the performance of blast furnace operation. Experiments have shown that a number of interesting phenomena appear in blast furnace operation. These phenomena involve rich granular dynamics which currently attract strong interest from a wide scientific and engineering. However, previous work on this area, limited by the research techniques, is predominantly at large scales focusing on phenomenological descriptions, but rarely touching on the basic fundamentals governing these phenomena. A novel discrete element simulation at an individual particle level can overcome these problems. For this purpose, this work conducts a systematic study of these important phenomena, including crater formation, coke collapse, creep motion and particle percolation, by use of the discrete element method (DEM). The experiments and simulations conducted in the impact of a particle stream onto a particle bed using a 20 slot model suggest that the DEM can reproduce the experimental results well under comparative conditions. The crater size is shown to be affected by the discharging rate, discharging height and materials properties, and is related to the ratio of the input energy from the falling stream to the inertial energy from the original packing. Fundamental understanding of coke collapse based on three different configurations: batch charging, self loading and load impact have been investigated. It was found that coke collapse is a kind of continuous avalanche due to top layer particles spreading. Apparent frozen layer under rapidly flowing layer is not stationary and slowly creep motion can be detected at an arbitrary depth. The mean velocity of creep motion decays exponentially with depth. Percolation happens due to both gravity and strain. The percolation velocity under gravity is much greater than that under shear. Size ratio effect is most significant. For size ratio smaller than threshold gravity induced percolation dominate otherwise shear due to the descending of the packed bed. Additionally, this work demonstrates the value of DEM as a tool for complementing experimental observations.

Doctor of Philosophy / In this thesis an examination is made of the vibro-replacement technique for the stabilisation of cohesive soils. Improvement is achieved by the formation of stiffer columns of granular material within the soil deposit using a large cylindrical vibrator referred to as a vibroflot. Granular piles (also termed stone columns) are used either singly or in small groups to supoort isolated footings or large numbers are installed in a regular array to support widespread loads. Each of these modes of application are investigated.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 188-205). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of California, San Diego, 2000. / Vita. Includes bibliographical references.