So how hard does a head hit a disk?

A model which appears to provide improved estimates of representative forces, pressures, etc., during a head/disk collision is presented. This model takes account of asperity deformation and the statistical nature of asperity interaction. What results is a total contact force of the order of 0.2 newtons for a duration of the order of a few microseconds. These values check with physical observations made by others. The model further yields contact areas, expected numbers of contacting asperities, and mean contact pressures. The authors apply the model to a variety of systems to gauge the effects of different incident velocities, alternative slider sizes, varying the interface topography, etc.<>