Mechanical and Civil Engineering Seminar

Granular materials have fascinating similarities to conventional matter. Then can flow, seemingly like liquids, or they can exist in disordered solid-like states. They also have intermediate glassy-like states. But, despite similarities to conventional matter, they break the rule book in critial ways. They can exhibit highly fluctuating behavior, but they are not thermal. The source of granular fluctuations comes from external driving, and the fact that grain interactions are dissipative means that understanding the nature of 'phase transitions' and fluctuations must involve new approaches. A particularly important transition for granular materials, referred to as jamming, occurs between granular fluid and solid 'states'. This transition has been extensively studied using model systems of frictionless particles. However, we have recently shown that particles with friction have much richer properties near jamming. I will begin with an introduction that considers key properties of granular materials. I will then explore some of the novel statistical and mechanical properties of dense granular materials. Key to our work are novel techniques for determining all physical properties of 2D and 3D granular systems at the particle scale.