FREE-VIBRATION CHARACTERISTICS OF ISOTROPIC AND LAMINATED ORTHOTROPICSPHERICAL CAPS

This paper deals with the free vibration characteristics of isotropic and laminated orthotropic spherical caps. A first order shear deformab le semi-analytical shell finite element has been used to obtain axisym metric and asymmetric modes of vibration. Two geometric configurations , namely deep and shallow shells, have been considered in the analysis . Both thick and thin ranges of thickness ratio are studied. The effec ts of thickness ratio, shallowness, material orthotropy and lay-up hav e been studied. An attempt has been made to explain some of the vibrat ional characteristics by observing the energies in various modes of vi bration. (C) 1997 Academic Press Limited.