FREE-VIBRATION ANALYSIS OF ORTHOTROPIC THICK SHELLS OF REVOLUTION USING DISCRETE LAYER THEORY

A two-noded finite element is presented for the analysis of thick orth otropic layered shells of revolution based on the discrete layer theor y. The effects of transverse shear deformation and rotary inertia are taken into consideration. A piece-wise linear variation of the in-plan e displacements across the thickness is assumed. The displacements are expanded in a Fourier series in the circumferential direction, as thi s reduces the order of the problem facilitating the evaluation of both symmetric and asymmetric circumferential modes of vibration. The effe ct of piece-wise linear variation on the representation of the shear d eformation is studied by means of varying the number of layers across the thickness. The representation and the effect of the boundary condi tions are discussed. Results are presented for spherical shells.