STICK-SLIP DYNAMICS OF A ONE-DIMENSIONAL ARRAY OF PARTICLES

The frictional motion of a linear array of parallel identical cylinder s on a horizontal plane is studied both experimentally and analyticall y. An ''irregular'' stick-slip motion is observed in experiments. Howe ver, statistics on the forces before and after each slip show stable a verage behavior. We find that global dynamic and static coefficients o f friction of the system increase with the number of particles. The or ganization of the rotations of particles appears as regions with chara cteristic lengths intermediate between the particle size and the size of the system. The mechanisms leading to these spatial patterns are st udied analytically and are shown to be related to the interplay of the Coulombic friction law and the geometrical frustration of rotations. A simple argument based on the variation of the global friction force with the applied force on the array is proposed to account for the sli p amplitude distributions observed in experiments.