Axisymmetric vibration analysis of laminated hollow cylinders with ring stiffeners

This paper presents an axisymmetric vibration analysis of laminated hollow cylinders composed of monoclinic layers and stiffened by ring stiffeners. A successive approximation approach, which is based on a transfer matrix and then an equivalent stiffness matrix formulation, is used to enable three-dimensional solutions to be found. It is assumed that the ring stiffeners are attached to the lateral surfaces of the cylinder and only provide elastic supports in radial direction. These constraints are imposed by using Lagrange multipliers to couple the responses of a number of vibration modes of corresponding cylinders without stiffeners. Using this method the natural frequencies of a stiffened cylinder are found to be the eigenvalues of a constraint matrix and the predictions can be arbitrarily close to the exact three-dimensional solutions.