Free vibrations and random response of an integrally-stiffened panel

Abstract

The free vibrations and random response to jet noise of an integrally-stiffened five-bay panel have been studied both theoretically and experimentally. A finite element approach was used to represent the panel for both parts of the study, and the predictions were verified by measurements on a model panel integrally machined from solid aluminum stock. The comparison between predicted and measured vibration modes and frequencies revealed good correlation of frequencies while the correlation of mode shapes was only fair, especially for higher modes. The predicted modes and frequencies we re used in a modal analysis of the panel's response to jet noise with a consistent finite element method being introduced to calculate the required cross-spectral modal force terms. Quantltative agreement between predicted and measured RMS stresses and displacements was realized, whereas only qualitative agreement was obtained for the associated spectra.