Granular Material Property Changes

It’s odd that granular materials are so prevalent and impact so much of our existence yet we know very little about predicting some of their most essential property changes.   In evaluating the properties of granular materials you are faced with the dichotomy of the same material either manifesting solid or liquid like properties depending upon circumstance.  A granular material such as simple sodium chloride can be packed into solid form or dry pour flowing like a liquid without change to microstructure of the granular element.  

In attempting to use most material science models to understand and determine the breakpoint for granular materials moving from a solid to liquid like flow state there are several approaches taken – none of which are satisfactory.   Continuum models don’t work because they breakdown at the point of liquid like flow when the unit under study can no longer be looked at as a whole and the discrete element model in which each grain is looked at uniquely won’t work because it is too computationally intensive, as pointed out by Dr. Antioette Tordesillas, University of Melbourne, Department of Mathematics and Statistics, Mechanics and Granular Media Group, who suggests the use of an enriched continuum model which is a hybrid of the continuum and discrete element model – this allows use of the continuum approach plus information about the granular material’s microstructure.   

The results observed by Dr. Tordesillas afford a higher resolution view of the solid to liquid transition point than either method alone and shows the phenomena of shear bands observed at the point the granular microstructure changes from solid to liquid properties.   These shear bands appear to be the key to identifying the structural failure mode causing the movement from solid to liquid state.   

Since granular materials comprise a great deal of our environment and are used in one way or another in almost everything we do, use and encounter, what are your thoughts regarding enhancing this modeling?  And do you have any recommendations for approaching such a project utilizing Six Sigma methodologies?  It could be used in more precisely determining the liquefaction hazards in earthquake prone areas and in potentially improving numerous manufacturing processes.   Also - anyone have access to an underutilized Cray computer?

Vinny