Evolution of microstructure in granular materials: Experimental results

This paper is concerned with experimental study of micro-kinematics of 2D granular materials (Schneebeli rods). Our measurements provide positions and displacements of rods centres and allow an experimental analysis of contacts evolution during a test. It is demonstrated that, even for complex loading with rotation of principal axes, the changes in statistic contact distribution are closely related with the macroscopic incremental strain.