Investigation of the Transmission Loss Behavior of an Advanced Grid-Stiffened Structure

The vibroacoustic behavior of an advanced grid-stiffened (AGS) composite structure which is reminiscent of a mock-scale fairing has been investigated. Both finite element analysis (FEA) and experimental modal analysis have been performed and the results corroborated. The lightly-coupled structurally-dominant modes and acoustically-dominant modes can be used to determine the structural acoustic coupling coefficients for the fairing. In addition, the certain critical structural acoustic frequencies have been computed. These results can be assimilated in order to provide insight into the theoretical performance limits of various potential transmission control mechanisms, including geometry or property tuning, the inclusion of passive control materials, or the addition of secondary structural and/or acoustic control inputs.