Our Experiment

A two dimensional granular system is represented by a hexagonal array of cylinders. The aluminum cylinders are an inch in diameter, and marked on one end with two small spots for rotation tracking. The cylinders are pushed slowly down an aluminum track with a stiff driving force at less than a millimeter per second. Force is measured at the pushing end of the array, and a small block is used on the other end for confinement. Our goal is to understand the bulk properties of this system from the basic interparticle contacts.

Why study granular materials?

Because they are interesting! Granular materials (such as sand, coffee beans, grains, coal, etc.) are made of solid particles, yet large collections of them behave differently than solids. Granular materials can flow, for instance, but they do not flow like a normal liquid such as water. Exactly how the macroscopic behavior arises from the inter particle forces is not fully understood.
Granular materials are important in industry. Agriculture, mining, and the pharmaceutical industries need to work with grains. Liquid transport is 20% more efficient than grain transport.
Many natural phenomena involve granular materials. Avalanches, earthquakes, beaches, and planetary rings are only a few of these.

This is a small movie of our experiment. A two dimensional granular medium is represented by an array of aluminum cylinders. Movie is 120 times faster than actual experiment.

	Our Experiment A two dimensional granular system is represented by a hexagonal array of cylinders. The aluminum cylinders are an inch in diameter, and marked on one end with two small spots for rotation tracking. The cylinders are pushed slowly down an aluminum track with a stiff driving force at less than a millimeter per second. Force is measured at the pushing end of the array, and a small block is used on the other end for confinement. Our goal is to understand the bulk properties of this system from the basic interparticle contacts. Why study granular materials? Because they are interesting! Granular materials (such as sand, coffee beans, grains, coal, etc.) are made of solid particles, yet large collections of them behave differently than solids. Granular materials can flow, for instance, but they do not flow like a normal liquid such as water. Exactly how the macroscopic behavior arises from the inter particle forces is not fully understood. Granular materials are important in industry. Agriculture, mining, and the pharmaceutical industries need to work with grains. Liquid transport is 20% more efficient than grain transport. Many natural phenomena involve granular materials. Avalanches, earthquakes, beaches, and planetary rings are only a few of these.




	This is a small movie of our experiment. A two dimensional granular medium is represented by an array of aluminum cylinders. Movie is 120 times faster than actual experiment.