LARGE-AMPLITUDE VIBRATIONS OF UNSYMMETRICALLY LAMINATED IMPERFECT THICK CIRCULAR PLATES ON AN ELASTIC-FOUNDATION

A previous non-linear shear-deformable theory for the axisymmetric def ormation of an unsymmetrically laminated circular plate composed of cy lindrically orthotropic layers is adopted. Effects of transverse shear , rotatory inertia, geometric initial imperfection and Winkler, Paster nak and non-linear Winkler models of elastic foundations are included in the analysis. Equations of motion are expressed in terms of the tra nsverse displacement, rotation and stress function. The plate edge is assumed to be elastically restrained against rotation. The Fourier-Bes sel series is used for a multi-mode solution to these equations. Numer ical results for non-linear fundamental free vibrations of the plate a re presented for various boundary conditions, radius-to-thickness rati os and geometric imperfections. Present results are also compared with available data.