We investigate autogenous fragmentation of dry granular material in rotating
cylinders using two-dimensional molecular dynamics. By evaluation of spatial
force distributions achieved numerically for various rotation velocities we
argue that comminution occurs mainly due to the existence of force chains. A
statistical analysis of theses force chains explains the spatial distribution
of comminution efficiency in ball mills as measured experimentally by Rothkegel
and Rolf. For animated sequences of our simulations see
http://summa.physik.hu-berlin.de/~kies/Research/RotatingCylinder/rotatingcylind
er.htmlComment: 15 pages, 13 figure