A formalism for handling problems of wave propagation and forced vibration in ribbed plates is presented. A general solution is obtained for the forced vibration of an infinite thin plate, periodically stiffened by identical, uniform ribs. The ribs are idealized as parallel line attachments capable of exerting line forces and line moments upon the plate, and the magnitudes of these forces and moments are related to the motion of the plate through the impedances of the ribs and plate. The assumption of an externally applied pressure excitation, which varies harmonically in time and in the plane of the plate, permits an explicit solution, and the principle of superposition is then used to construct the solution to an arbitrary excitation. By setting the amplitude of the harmonic excitation equal to zero, an equation for the free modes of the ribbed plate is derived.
Subject Classification: 20.15.
