Particle Analysis of Material Behavior—A Note on Continuum Assumptions
Continuum models of materials have dominated our approach to the analysis of material behavior. Recently a number of discrete particle methods have been proposed which offer a different view of the physics of materials. Here I review some of these particle methods and attempt to highlight the new perspective which they offer on the relationship between the microworld and the macroworld. An example is presented which shows how structures within a material may vary greatly in size near 'critical points' making the concept of an elementary volume problematic. The possibility of the states of failure in granular materials being critical points is proposed, based on a model of avalanche type failure of a sand pile and a model of the size of microfractures in a soil.