Granular Matter

Focussing on the basic mechanics and underlying physics of granular material, Mechanics of Granular Matter starts with an introduction to contact mechanics of individual particles before moving on to a discussion of the structure of force chain networks and the influence on bulk mechanical properties of granular solids and granular flows. Furthermore, a preliminary multi scale framework is proposed for the nonlinear mechanics and strain localization in granular materials.

Explaining the science contained in a simple assembly of grains—the most abundant form of matter present on Earth. Granular media—composed of vast amounts of grains, consolidated or not—constitute the most abundant form of solid matter on Earth. Granular materials assemble in disordered configurations scientists often liken to a bag of marbles. Made of macroscopic particles rather than molecules, they defy the standard scheme of classification in terms of solid, liquid, and gas. Granular materials provide a model relevant to various domains of research, including engineering, physics, and biology. William Blake famously wished “To See a World in a Grain of Sand”; in this book, pioneering researchers in granular matter explain the science hidden behind simple grains, shedding light on collective behavior in disordered settings in general. The authors begin by describing the single grain with its different origins, shapes, and sizes, then examine grains in piled or stacked form. They explain the packing fraction of granular media, a crucial issue that bears on the properties displayed in practical applications; explore small-scale deformations in piles of disordered grains, with particular attention to friction; and present theories of various modes of disorder. Along the way, they discuss such concepts as force chains, arching effects, wet grains, sticky contacts, and inertial effects. Drawing on recent numerical simulations as well as classical concepts developed in physics and mechanics, the book offers an accessible introduction to a rapidly developing field.

Powders have been studied extensively because they arise in a wide variety of fields, ranging from soil mechanics to manufacture of pharmaceuticals. Only recently, however, with the deepening understanding of fractals, chaos, 1/f noise, and self-organization, has it been useful to study the mechanical properties of powders from a fundamental physical perspective. This book collects articles by some of the foremost researchers in the field, including chapters on: the role of entropy in the specification of a powder, by S.F. Edwards (Cambridge); discrete mechanics, by P.K. Haff (Duke); computer simulations of granular materials, by G.C. Barker (Norwich); pattern formation and complexity in granular flow, by R.P. Behringer and G.W. Baxter (Duke); avalanches in real sand piles, by A. Mehta (Birmingham); micromechanical models of failure, by M.J. Adams (Unilever) and B.J. Briscoe (Imperial College); mixing and segregation in particle flows, by J. Bridgwater (Birmingham); and hard-sphere colloidal suspensions, by P. Bartlett (Bristol) and W. van Megen (Melbourne).

Dry granular materials, such as sand, sugar and powders, can be poured into a container like a liquid and can also form a pile, resisting gravity like a solid, which is why they can be regarded as a fourth state of matter, neither solid nor liquid. This book focuses on defining the physics of dry granular media in a systematic way, providing a collection of articles written by recognised experts. The physics of this field is new and full of challenges, but many questions (such as kinetic theories, plasticity, continuum and discrete modelling) also require the strong participation of mechanical and chemical engineers, soil mechanists, geologists and astrophysicists. The book gathers into a single volume the relevant concepts from all these disciplines, enabling the reader to gain a rapid understanding of the foundations, as well as the open questions, of the physics of granular materials. The contributors have been chosen particularly for their ability to explain new concepts, making the book attractive to students or researchers contemplating a foray into the field. The breadth of the treatment, on the other hand, makes the book a useful reference for scientists who are already experienced in the subject.

This book is a systematic introduction to a new and exciting field of patterns in granular matter. Granular materials are collections of discrete macroscopic solid grains with a typical size large enough that thermal fluctuations are negligible. Despite this seeming simplicity, properties of granular materials are different from conventional solids, liquids and gases due to the dissipative and highly nonlinear nature of forces among grains. The last decade has seen an explosion of interest to nonequilibrium phenomena in granular matter among physicists, both on the experimental and theoretical side. Among these phenomena, one of the most interesting is the ability of granular matter upon mechanical excitation to form highly ordered patterns such as ripples, avalanches, or bands of segregated materials. This book presents a comprehensive review of experiments and novel theoretical concepts needed to understand the mechanisms of pattern formation in granular materials. This book is written for experienced physicists interested in this new rapidly developing field, as well as young researchers and graduate students entering this field. We hope that both experimentalists and theorists already working in the field will find it useful.

Granular matter displays a variety of peculiarities that distinguish it from other appearances studied in condensed matter physics and renders its overall mathematical modelling somewhat arduous. Prominent directions in the modelling granular flows are analyzed from various points of view. Foundational issues, numerical schemes and experimental results are discussed. The volume furnishes a rather complete overview of the current research trends in the mechanics of granular matter. Various chapters introduce the reader to different points of view and related techniques. New models describing granular bodies as complex bodies are presented. Results on the analysis of the inelastic Boltzmann equations are collected in different chapters. Gallavotti-Cohen symmetry is also discussed.

This is a monograph written for the young and advanced researcher entering the field of wet granular matter, and is keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis.

This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter, keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as a ternary system consisting of the grains, a primary, and a secondary fluid. After generally addressing wetting phenomena and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects like existing books on this topic do, this book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. It spans a wide scope of questions, ranging from possible general principles behind the emergence of structure and pattern, to the interpretation of geological outcrop features we encounter in nature.