Acoustics Analysis of Hard Disc Drive Covers Considering an Internal Drive Noise Source

This paper presented methods that allow for the optimization of a disc drive cover using analytical acoustic techniques. The methods account for the noise that is radiated off the cover as well as internal noise sources in the drive. Two acoustics analyses were shown. First, an uncoupled analysis was done, which considers only the radiated noise from the cover. A detailed finite element model of one cover was made. The surface velocities due to an internal measured pressure were determined. The velocities were transferred to an acoustic model of the cover. An indirect boundary element method was used to determine the sound power from the cover. It was found that compared to experimental results, only the first peak in the sound power curve could be attributed to the cover. Next, a coupled acoustics analysis was done which modeled the disc drive as a rigid box with a flexible top, and an internal noise source. The eigenvalues and eigenvectors from the finite element model were transferred to a boundary element model of the cover. A cavity was created in which a spherical point source was added. The amplitude and the frequency dependence of the source were varied until sound power predictions and experimental results agreed for one cover. The method was then extended to three other covers. Comparisons with experiments showed that the gasket seal that bonds the cover to the drive also needs to be included in the model to get agreement. With the methods presented in this paper, the cover geometry and material composition can be varied to see effects to sound power. A more sophisticated sound source could be developed based on sound intensity data to better represent idle conditions. In addition, sources could be developed for SEEK conditions to further optimize covers.

Language

  • English

Media Info

  • Media Type: Audiotape
  • Features: Figures; References;
  • Pagination: pp 795-805
  • Monograph Title: Noise-Con 04. The 2004 National Conference on Noise Control Engineering

Subject/Index Terms

Filing Info

  • Accession Number: 01054378
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 26 2007 12:24PM