A semianalytical solution for free vibration analysis of stiffened cylindrical shells

Based on a semianalytical solution of the state-vector equations, we propose a novel mathematical model for the free vibration analysis of cylindrical shells with stiffeners and for cylindrical panels with discontinuities in thickness and/or with cutouts.The shell and stiffeners are regarded as three-dimensional elastic bodies, but the same quadrilateral element is used to discretize the shell and stiffeners.The method accounts for the compatibility of displacements and stresses on the interface between layers of the laminated shell and stiffeners, for transverse shear deformation, and of course for the rotational inertia of the shell and stiffeners.To demonstrate the model's excellent predictive abilities, several examples are analyzed numerically.The model can be easily modified to solve problems of stiffened piezolaminated plates and shells, or plates and shells with patches made of a piezoelectric material.