The activities to be undertaken under this Research Planning Grant are focused on the preliminary formulation of an improved method for investigating structure acoustics problems having significant damping. During the course of the effort, several appropriate models of a duct and other type endosures having sound absorptive materials will be formulated and investigated. This preliminary work coupled with consultation with leaders in the field, is expected to lead to the development of a highly competitive, sharply focused, research proposal within the field of structural dynamics.***//