A simulation scheme with coupled dynamic models for the slider and the suspension lift-tab during the unloading process of a hard disk drive

A numerical scheme was developed to simulate the interaction between the suspension lift-tab and the ramp of a load/unload-type hard disk drive with consideration of the contact and separation states. The suspension stiffnesses and effective masses were determined based on experiments and finite element analysis. The slider motion was simulated with a degenerated two-degree-of-freedom model, and the results were used as input to a single-degree-of-freedom model for the lift-tab motion. The ramp profile was converted, based on the lateral velocity of the suspension, to a vertical displacement versus time. Computational efficiency was achieved by using a head–disk constraint, instead of a full air-bearing solution, based on dual-scale considerations. The simulation results show that the maximum indentation depth at the tab–ramp engagement increases with an increase in the effective masses, lateral velocity, or ramp angle or with a decrease in the contact stiffness. The bouncing height and bouncing distance of the lift-tab increase with an increase in the contact stiffness, effective masses, lateral velocity, or with a decrease in the suspension stiffnesses. The air-bearing separation time decreases as the suspension stiffnesses, lateral velocity, or ramp angle increases. The coefficient of friction of the tab–ramp interface was found to have a slight influence on the lift-tab behavior on the inclined portion of the ramp.