Origin of rigidity in granular solids – Bulbul Chakraborty

Date: Thu. April 11th, 2013, 4:15 pm-5:15 pm
Location: Rockefeller 301

Granular materials such as sand or rice grains behave in ways that are often counterintuitive. An example is “footprints on sand” which owe their origin to a phenomenon known as dilatancy. Our intuition often fails because dry granular materials are non-cohesive, and live at zero temperature. The distinction between gases, liquids and solids is ill understood. These materials can solidify via non-equilibrium pathways in which applied stresses or boundary constraints play a crucial role. A striking example of this is shear-jamming, where an amorphous granular solid is created through the application of shear. This is in sharp contrast to our usual experience of shearing leading to flow. In this talk, I will illustrate some of the fascinating properties of dry grains, and describe a theoretical framework for understanding how these materials “solidify.”