Nonlinear vibrations of cantilevered circular cylindrical shells in contact with quiescent fluid

Large-amplitude vibrations of liquid-filled cantilevered (clamped-free) circular cylindrical tanks are studied theoretically for the first time. The influence of liquid height and initial geometric imperfections is investigated in detail. The tank motions are described by a nonlinear model based on Flügge׳s shell theory, and the liquid motions are modelled by means of linearized potential flow theory. Equations of motion are obtained using the extended Hamilton׳s principle and are discretized by expanding the solution with trigonometric functions in the circumferential direction and the cantilevered beam eigenfunctions in the axial direction. The geometric boundary conditions are satisfied exactly, while the natural ones are satisfied in an energy minimization sense. The system is integrated numerically by employing the appropriate modal composition of the solution to guarantee convergence. Results are presented in the form of frequency-response curves in the neighbourhood of the lowest natural frequency. It is found that the response may be of softening or hardening type, depending on the liquid height and the imperfection parameters.