Interpolation-Based Condensation Model Reduction Part 1: Frequency Window Reduction Method Application to Structural Acoustics

Abstract

Degree of freedom model reduction and frequency windowing via interpolation are combined for application to acoustic finite element analysis. Projection operators are employed for the model reduction or condensation process. Interpolation is then introduced over a user defined frequency window, which can have real and imaginary boundaries and be quite large. Hermitian (which require derivative information) interpolation functions as well as standard Lagrangian functions, which can be linear, quadratic or cubic, have been used to construct the interpolation windows. For 1D windows, the location of interior evaluation points can be varied to increase accuracy. Excellent results are obtained for the example problems, even for large degree of freedom (DOF) reduction and large frequency windows containing numerous resonance (eigenvalues). The solution for the reduced models within the interpolation windows accurately indicate the location of the resonance. The program FWR (Frequency Window Reduction) is written in Fortran 90 and has the ability to read in third party generated finite element models.

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 1999
Accession Number
ADA369086

Entities

People

  • C. T. Dyka
  • L. D. Flippen Jr.
  • R. P. Ingel

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • C4I

DTIC Thesaurus Topics

  • Accuracy
  • Acoustics
  • Boundaries
  • Complex Variables
  • Composite Materials
  • Differential Equations
  • Eigenvalues
  • Equations
  • Finite Element Analysis
  • Frequency
  • Materials
  • Materials Science
  • Military Research
  • Resonance
  • Resonant Frequency
  • Standards
  • Two Dimensional

Readers

  • Control Systems Engineering.
  • Operations Research
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.