Vibration isolation provided by attaching a rib on a panel

The response of a fluid‐loaded single‐ribbed panel was derived and discussed by the authors in the last meeting [J. Acoust. Soc. Am. 58, S42 (A) (1975)]. In that paper the panel was simulated by a membrane. The tension in the membrane was made frequency dependent so that it would simulate the dispersive properties era plate. In this paper emphasis is placed on the type of vibration isolation that a rib can provide between a localized driving field and a vibration sensitive observer located on the panel across the rib. The finding can be related to the vibration isolation that a rib provides against free waves on the panel. It is shown that the isolation that can be provided by the rib can be severely limited, in the lower frequency range, by moderate fluid loading. The frequency range is roughly confined to that below the critical frequency of the panel It is argued that the inclusion of fluid loading in structural vibration problems may be imperative, not only in situations in which estimates of acoustic...