Modal analysis of acoustically-loaded structures via integral equation methods

Abstract

In this paper a numerical method for determining the modal properties of a structure in contact with an acoustic medium is explored. The acoustic field is reformulated as an integral equation. The application of collocation transforms the problem into one of solving a non-linear eigenvalue problem. Approximation of each matrix component by a quadratic polynomial in the wavenumber range transforms this into a standard generalized linear eigenvalue problem. The numerical method is applied to the two-dimensional problem of a square with one face assuming dynamic properties, the other faces are rigid with the acoustic field lying exterior to the square. A set of tests are carried out and results given.