Dynamic analysis of stickslip motion
Abstract
The most widely accepted cause of stickslip motion is that the static (mu(sub s)) exceeds the kinetic friction coefficient (mu(sub k)), or that mu(sub k) drops rapidly at small speeds. Using a dynamic analysis it is shown that the rate of increase of mu(sub s)(t) with sticking time is a crucial parameter in addition to the condition of mu(sub s) greater than mu(sub k), and that stickslip may occur even if mu(sub k) increases with speed V. A general equation is derived which describes the stickslip amplitude (x(sub s)) in terms of substrate speed V(sub 0), spring stiffness K and damping gamma, for an arbitrary mu(sub s)(t) and a linearized mu(sub k)(V), in contrast to a set of previous equations derived by Brockley et al. for an exponential mu(sub s)(t) and a linearized mu(sub k)(V) (1) . Additional equations are developed for the 'saturation' speed (V(sub ss)), below which x(sub s) is independent of V(sub 0), and also for a critical substrate speed V(sub c) above which the stickslip amplitude vanishes. At speeds between V(sub ss) and V(sub c) the stickslip amplitude generally decreases with increasing V(sub 0), K and gamma. Depending on the detailed conditions, different sliding modes including smooth sliding, nearharmonic oscillation or stickslip can result. Equations developed in this paper suggest practical methods of reducing or eliminating stickslip for a general system.
 Publication:

Wear
 Pub Date:
 April 1994
 Bibcode:
 1994Wear..173....1G
 Keywords:

 Contact Loads;
 Dynamic Control;
 Dynamic Response;
 Dynamic Stability;
 Sliding Friction;
 Coefficient Of Friction;
 Damping;
 Linearization;
 Substrates;
 Mechanical Engineering