WAVE-PROPAGATION ALONG LONGITUDINALLY PERIODICALLY SUPPORTED OR STIFFENED PRISMATIC PLATE ASSEMBLIES

A method is presented for computing propagation constants of longitudi nal Free wave propagation in a longitudinally prismatic plate assembly which is supported or transversely stiffened at longitudinally period ic intervals. The method combines a special complex Fourier series app roach with the Wittrick-Williams algorithm, taking into account the su pporting structures or transverse stiffeners by using Lagrangian multi pliers, It enables Fourier series based methods and computer programs for natural frequency analysis to be readily used instead to investiga te free wave propagation problems. it can be extended to handle other types of periodic structures. Three numerical examples of plate assemb lies of different cross-sections are given and lead to some useful con clusions. (C) 1995 Academic Press Limited