Thesis (Ph.D.)--Lehigh University, 2000. / Source: Dissertation Abstracts International, Volume: 60-12, Section: B, page: 6187. Adviser: Yong W. Kim.

Thesis (M.S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2004. / Carlos Santamarina, Committee Chair ; Glenn Rix, Committee Member ; Paul W. Mayne, Committee Member. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Department of Physics, December 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 197-212). Also available in electronic version.

Master of Science / Department of Computer Science / Daniel Andresen / Modern techniques for simulating granular matter can produce excellent quality simulations, but usually involve a great enough performance cost to render them ineffective for real time applications. This leaves something to be desired for low-cost systems and interactive simulations which are more forgiving to inaccurate simulations, but much more strict in regards to the performance of the simulation itself. What follows is a proposal for a method of simulating granular matter that could potentially support millions of particles and several types for each particle while maintaining acceptable frame rates on consumer level hardware. By leveraging the power of consumer level graphics cards, effective data representation, and a model built around Cellular Automata a simulation can be run in real time.

[pt] O propósito deste trabalho é propor um modelo teórico axiomático, que descreva o comportamento termomecânico de materiais granulares, fundamentado em uma descrição física simples, do que entende-se por material granular. No capítulo I, faz-se uma revisão bibliográfica, objetivando uma visão geral do estado da arte e delinear a importância do estudo de materiais granulares. No capítulo II, utiliza-se um método axiomático estabelecendo-se as equações de balanço que descrevem o comportamento termodinâmico de materiais granulares. No capítulo III, utilizando-se um outro método axiomático, analisa-se algumas condições de contorno para materiais granulares. No capítulo IV, estuda-se restrições internas em materiais granulares, exemplificando-se algumas. Finalmente no capítulo V, aplica-se o embasamento teórico dos capítulos anteriores, na solução do problema de escoamento de um material granular entre placas paralelas. / [en] The aim of this work is to establish an axiomatic theoretical model, for description of the thermomechanical behavior of granular materials, based on a simple physical description of what mean granular materials. On the first chapter, it s make an overview of the acctual state of the arte, giving the real importance of the study of granular materials. On the second chapter, by using an axiomatic method, the balances equations for thermomechanical behavior of granular materials, was established. On the the III, by using another axiomatic method, some boundary condictions for granular materials, was analysed. On the chapter IV, by using a coceptual model for internal constraints, some internal constraints for granular materials, was exemplified. At least, on chapter V, the theoretical backgoung established in the previous chapter, is applied to solve the problem of granular flow between two parallel plates.

Debris flows, avalanches and other geophysical mass flows pose a significant hazard to settlements in or near mountainous regions. Understanding the physical processes that govern these flows is an essential part of hazard assessment and mitigation strategies. This thesis addresses two aspects of geophysical mass flows: flow self-channelisation due to the formation of lateral levees, and granular shocks, which occur when a rapidly-moving debris flow or avalanche collides with an obstacle. We present the results of large-scale debris flow experiments in which the flow is channelised by coarse-particle levees that form at the flow margins. The flow surface velocities are measured with high speed overhead photography, and the deposits both sampled to obtain the grain size distribution and excavated to recover the deposited locations of tracer pebbles that were introduced in to the flow. We propose a model, supported by evidence from the large-scale experiments, that describes in detail the size segregation and kinematic transport processes responsible for the deposition of lateral levees. The second problem addressed in the thesis concerns granular shocks, or jumps, which are rapid changes in the depth and velocity of granular avalanches. We investigate these through experiments in which a falling jet of granular material impacts on an inclined plane, generating a steady granular jump, which is either teardrop-shaped or 'blunted'. Numerical solutions of a depth-averaged flow model agree quantitatively with many of the observed flow features. We use this model show that the transition between the teardrop-shaped and blunted jump regimes corresponds to a transition between two shock reflection structures, known as a regular and a Mach shock reflection. On planes inclined at a shallow angle, we demonstrate a wide variety of unsteady and channelised flows, which occur due to the complex interaction between flowing and stationary regions of granular material.

No description available.

When many objects make contact, they will adopt some collective behavior. For example, sand particles jam together to form a "solid" aggregate (a beach) that you can walk on, hair collects into locks, and sticks can be arranged to form nests and dams. In all of these cases, the collective behavior depends on both the "granular" nature of the objects, i.e. their tendency to jam or rearrange, and their "elasticity," that is, their tendency to deform in response to load. For example, both sand, which is relatively stiff, and cells, which are relatively soft, can rearrange and "flow," however, jammed aggregates of these objects (beaches and biological tissues) vary drastically in their mechanical properties. Here we will unravel the interplay between elasticity and granularity by first separately considering how individual soft objects deform, and many hard particles jam. We will then combine these behaviors step-by-step. First we will consider a single object (an elastic plate) in contact with a hard ring. Then, we will study rearrangement and deformation in two systems where an aggregate made up of stiff particles comes in contact with slender deformable objects, the former reminiscent of plant roots digging into the dirt, and the latter akin to coffee beans jammed in an air-tight bag. Finally, we will consider a system of slender contacting elastic objects, and find that the collective behavior results in the emergence of order. This thesis will illuminate novel physics and functionalities -- building materials which are reformable in real-time and soft robots which can arbitrarily deform, and along the way we will develop tools that could be used to study such diverse systems as the jamming of fibers such as in felt or a collagen network, the properties of a knitted scarf, and the growth and shape of villi in the gut.

No description available.