Modeling and Vibration Analysis of Spinning-Disk and Moving-Head Assembly in Computer Storage Systems

Abstract

Vibration of a spinning disk subject to a moving head, that is frequently encountered in computer storage system, is studied. The magnetic head moving on the spinning disk is modeled as a harmonically varying load traveling in the radial direction. The spinning disk responses are solved for analytically through an approach that employs the Galerkin’s method and some solution techniques. Examples of various loading conditions are then illustrated and discussed. The load’s moving speed was found to act as a driving frequency and it would cause resonances at certain speeds. The resonances caused by individual parameters were addressed and marked as critical Spinning speed and critical moving speed. A resonant equation that correlated the three parameters, disk spinning speed (Ω), load moving speed (v), and load frequency (ω), was derived and the corresponding resonant surfaces were shown in graphs. The resonant phenomena due to the interactions of parameters are then realized. The disk’s transient responses to moving loads are also illustrated. The results showed that a constant-amplitude moving load caused no oscillatory motion as it moved from fixed end to free end but it did cause oscillation as the load moved in reverse way. A harmonic moving load, however, always results in oscillations as expected.