Response of a fluid‐loaded panel supported by several ribs

Abstract

An infinite fluid‐loaded surface, idealized here as a membrane, is supported by two ribs of infinite impedance, situated at equal distances on either side of a third central rib which is driven by a prescribed line force. Formal exact solutions are readily obtained for the structural response and the radiated sound field, and these are simplified and interpreted on the basis that a fluid‐loading parameter at the coincidence condition is small. The arguments rely heavily on the asymptotic structure of the Green's function for the infinite fluid‐loaded membrane, as described at the 98th Meeting [D. G. Crighton, J. Acoust. Soc. Am. Suppl. 1, 66, S1 (1979)]. Parameter ranges in which resonances and antiresonances are to be found are determined, and explicit expressions are given for the amplitude of resonant and antiresonant responses in regard to the sound field, the drive‐point response, and the surface wave fields transmitted across the ribs. Arbitrary configurations of multiple ribs can be dealt with in a similar manner.