Change of scale in granular materials

This paper analyzes relationships allowing global variables to be deduced from local ones in granular materials. This change of scale is now clear for static variables but rather confusing for kinematic variables. This paper compares the various established formulations fur kinematic variables and also proposes original formulations. By running numerical simulations all the formulations in question are compared and thr basic premises to define the change of scale for kinematic variables in granular media put forward. (C) 2000 Editions scientifiques et medicales Elsevier SAS.