Modification Caused by Compliant Layers and Blankets in the Pressure Field Induced on a Boundary

Abstract

A primitive analytical tool to assess the modification in the response caused by introducing various combinations of flexible layers on panels is proposed and developed. The tool is primitive in the sense that quantities which characterize the dynamic system are expressed in terms of lumped parameters. It is thus subjected to many restrictions and limitations with which the user needs to become familiar if he is to employ the tool properly. The formalism is expressed in terms of a matrix that relates the response vector to an external drive vector that induces the response. An element of the matrix identifies the surface on which an external test drive is acting and the surface on which the resulting response is assessed. The general formalism is specialized to the case of a panel that is clad with a composite consisting of a compliant layer and a blanket. The resulting elements of the matrix are used to ascertain the modification factor that is associated with this kind of cladding. The modification factor assesses the change in the response, e.g., pressure field due to the treatment of the panel by the flexible layers. It transpires that in the case of an ideal blanket the modification factor of the composite flexible layer is equal to the product of the two modification factors. Each factor relates separately to the application of one of the two individual flexible layers. A few computational examples of interest are cited and briefly discussed.