Laboratory Simulation of the Response of Structures Exposed to Intense Acoustic Environments

Abstract

The primary state-of-the-art laboratory method for the evaluation of the response and fatigue characteristics of skin panels exposed to intense noise is the progressive-wave or parallel incidence test facility. This method obtains the highest sound-pressure levels per unit input power by minimizing the cross-sectional area of the duct and also maintains a relatively flat frequency response. However, many of the current configurations provide excessive radiation damping to the panel in its lower modes. This paper summarizes analytical and experimental investigations of the radiation damping of panels mounted in progressive-wave test sections. The results are presented in generalized form, which give the dependency of the radiation damping on the ratio of the panel area to test duct cross-sectional area and pertinent panel parameters. In addition, the paper reviews an analytical study of the response of panels to variable incidence progressive waves and to a reverberant field. These results demonstrate the possible future importance of reverberant fields as a replacement for progressive-wave tests.