Accession Number : ADA313303

Title :   Numerical Methods for Underwater Structural Acoustics.

Descriptive Note : Final rept. 1 Mar 94-30 Jun 95,

Corporate Author : MARYLAND UNIV COLLEGE PARK OFFICE OF RESEARCH ADMINISTRATION AND ADVANCEMENT

Personal Author(s) : Elman, Howard ; O'Leary, Dianne ; Saltz, Joel ; Stewart, Gilbert

PDF Url : ADA313303

Report Date : 19 APR 1996

Pagination or Media Count : 5

Abstract : This report represents the status of the project referenced above as of June 30, 1995, the conclusion of the term of this grant. The project centered on a problem in structural acoustics: to determine the reflection properties of an underwater object interacting with sonar signals. To generate representative problems, we have been using the SARA package produced by H. Allik and D. Moore of Boit Beranek and Newman, New London, CT. This code uses a finite/infinite (quadratic) element formulation in the frequency domain. The resulting linear system, which is complex symmetric, is currently solved with heavy dependence on secondary storage (i.e., disk) by Gaussian elimination using a frontal approach, with no pivoting for stability. This method has given adequate numerical results, even though it might be expected to fail due to resonances in the system. It is also likely to be too costly to handle large problems, especially for three dimensional models. Our goal has been to investigate two alternative approaches that we expect will alleviate these difficulties: the use of iterative methods and the use of parallel sparse solvers.

Descriptors :   *UNDERWATER ACOUSTICS, ALGORITHMS, FINITE ELEMENT ANALYSIS, ELASTIC PROPERTIES, MATHEMATICAL PROGRAMMING, NUMERICAL METHODS AND PROCEDURES, ITERATIONS, SONAR SIGNALS, UNDERWATER STRUCTURES, ACOUSTIC REFLECTION, ACOUSTIC RESONANCE.

Subject Categories : Acoustic Detection and Detectors
      Operations Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE