PREDICTION OF AEROELASTIC FLUTTER IN A HARD DISK DRIVE

An experimental technique to predict the onset of aeroelastic flutter of an enclosed computer memory disk is presented. The aerodynamic pressure is modelled as the sum of dissipative and circulatory linear operators, which subsumes as a special case the pressure generated in a thin hydrodynamic film between the disk and the wall. It is shown that the aeroelastic model parameters can be extracted from the frequency response function of the disk spinning at subcritical speeds. The aeroelastic parameters for an acoustically excited single disk at different enclosure gaps are derived for the speed range 6,000–19,800 rpm. The flutter speed predicted is strongly influenced by the enclosure gap and the substrate damping. A flutter speed as low as 35,000 rpm has been predicted. The technique can also be extended to predict the flutter speed in other systems including DVD and CDROM drives.