Self-Excited Oscillations of Two Elastic Half-Spaces
Two flat isotropic elastic half-spaces, of different material properties,
are pressed together and slide against each other with a constant
coefficient of friction. Although a nominally steady-state solution exists,
an analysis of the dynamic problem demonstrates that the steady solution can
be dynamically unstable. Eigenvalues with positive real parts give rise to
self-excited motion which occurs for a wide range of material pairs,
coefficients of friction, and sliding velocities (including very low speeds).
These self-excited oscillations are generally confined to the region near the
interface and can lead either to regions of loss-of-contact or to areas of
stick-slip. The mechanism responsible for the instability is essentially one
of destabilization of interfacial (slip) waves. It is expected that these
vibrations might play an important role in the behavior of sliding members
with dry friction.
Sliding With a Constant Coefficient of Friction