(Dr. Jerry Ginsberg, advisor)

"A Study of Methods for Frequency Domain Interpolation of Structural Acoustics Computations"

Abstract

In the project presented, the feasibility of interpolating frequency domain, structural acoustic data pertaining to the acoustic field of a submerged, hemi-capped cylinder subjected to a ring force applied at its mid-plane was investigated. The original data used in this project had been produced in a previous project using the Surface Variational Principle (SVP) formulation. The intention of the present work was to generate higher frequency resolution data for use in validating existing time domain, structural acoustic simulation tools.

In the course of implementing and verifying the interpolations that were undertaken it was necessary to identify an acceptable interpolation technique to be used throughout the project. Once a suitable technique had been chosen, a full solution of the SVP formulation, using the interpolated data, was implemented. This solution yielded the non-dimensionalized, vectors of series coefficients for the system displacement at the higher frequency resolution of the interpolated data. Once solved, the displacement coefficient vectors from the solution of the original problem were compared to the displacement coefficient vectors generated using the interpolated data. When this comparison was done, at data points found in the original problem solution which had not been used to generate the interpolation, it was possible to determine error introduced to the solution by interpolation. The error found was then analyzed as a function of the type and amount of data input to the interpolation procedure and relevant conclusions were drawn. It was found that the method of interpolation employed in this study was not adequate for validation of other time-domain solution methods, as it could not provide reasonable accuracy at intermediate (interpolated) frequencies.