Analysis of Friction-Induced Vibrations of Flying Head Slider in Near Contact Regime

Abstract

In order to investigate the severe slider vibrations and hysteresis behaviors of touch down and take-off processes in near contact regime, we numerically calculated the slider dynamics by using the 2-DOF model considering asperity contact, adhesive force of lubricant and friction force. As a result, we could find friction-induced vibration as follows : In the touch down process, the slider exhibits bouncing vibrations as the slider contacts with the disk surface. In the take-off process, the slider continues the bouncing vibration even if the nominal flying height becomes higher than that when the slider begins to contact with the disk surface. These bouncing vibrations and hysteresis phenomena are observed only when both lubricant force and friction force exist. In addition, the bouncing vibration is not simply periodic but contains many frequencies. From spectrum analysis of the slider vibrations up to 1 MHz, we can observe the many super harmosics and sub-harmonics. These analytical results agree well with the experimental ones. As a result, we can say that the severe contact vibration is a self-excited vibration of the slider related to both lubricant force and friction force.