Molecular dynamics study of dynamic contact and separation between tip and disk surface

Molecular dynamics simulations were performed to study contact and separation between tip and lubricants on disk surface. The effects of contact indentation depth, indentation velocity, separation velocity, adhesive energy, lubricant molecular structure and lubricating film thickness on interacting force were analyzed. The results indicate that the tip force exerted by lubricants is velocity-dependent. The tip force increases with increasing indentation velocity and separation force reduces with increasing separation velocity. The damping of branched molecule and thick lubricating film is high. The high adhesive energy of tip material can produce high separation force which reduces bouncing vibration.