Acoustic behavior of ribbed panels

Abstract

The paper describes the acoustic behavior of a panel in terms of the impulse response function. The original impulse response function describes a panel that may be immersed in an environment that may be composed of layered mechanical elements that can be defined by lumped surface impedances and of slabs of fluid-like media. It is assumed that the original impulse response function is known. Based on this knowledge a modified impulse response function is derived. The modification is caused by a specific attachment of ribs to the panel. It is shown that a proper modified impulse response function can be derived in terms of the known original impulse response function and the properties of the ribs. These properties are defined in terms of the locations, the line impedances and, when appropriate, the line moment impedances of the ribs. The forms and interpretations of the derivation are discussed in several situations of interest. The acoustic behavior of particular interest is comprised of the transmission of response on the panel and the reflection and transmission of a junction in which the panel is incorporated. (A junction is a boundary separating slabs of fluid-like media.)