Abstract
The onset of friction-vibration instability is sometimes attributed to the inverse variation in the friction force with the relative velocity of sliding whereby the friction-velocity gradient becomes high compared with the system damping coefficient. However, when account is taken of the effective contact stiffness of sliding surfaces, it is found that the instability of frictional vibrations is mainly dependent on the value of the total tangential contact stiffness of sliding surfaces as well as the system stiffness. The values of both the friction-velocity gradient (the slope of the friction-velocity curve) and the mass of the slider are found to have negligible effects on the stability of motion.