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A model is presented of a particle that interacts with two periodic potentials, representing two confining plates, one of which is externally driven. The model leads to a spectrum of rich behaviors in the motion of the top driven plate: a stick-slip, intermittent kinetic regime, characterized by force fluctuations, and two types of sliding above a critical driving velocity vc. Similar behaviors are typical of a broad range of systems including thin sheared liquids. A detailed analysis of the different regimes displays an interesting transition range between stick-slip and kinetic motion, omega -2 power spectra of the force over a wide range of velocities below vc, and a decrease of the force fluctuations that follows (vc-v)1/2 for v<vc. The velocity-dependent Liapunov exponents demonstrate that stick-slip dynamics is characterized by chaotic behavior of the top plate and the embedded particle. An equation is derived that provides a coarse-grained description of the plate motion near vc.
©1996 The American Physical Society
|68.15.+e||Surfaces and interfaces;|
|46.30.Pa||Friction, wear, mechanical contacts, and tribology|
|05.45.+b||Statistical physics and thermodynamics : Theory and models of chaotic systems|
|05.40.+j||Statistical physics and thermodynamics : Fluctuation phenomena|