Non linear vibrations of imperfect fluid-filled viscoelastic cylindrical shells

In this work the effect of geometric imperfections on the non-linear dynamics of simply supported viscoelastic fluid-filled circular cylindrical shells subjected to lateral harmonic load is studied. Donnell's non-linear shallow shell theory is used to model the shell, assumed to be made of a Kelvin-Voigt material type, and a modal solution with eight degrees of freedom is used to describe the lateral displacements. The Galerkin method is applied to derive a set of coupled non-linear ordinary differential equations of motion. The influence of shell geometry, flow velocity and dissipation parameter are studied and special attention is given to resonance curves and bifurcation diagrams. Obtained results show that geometric imperfections together with the viscoelastic dissipation parameter and internal fluid have significant influence on the nonlinear dynamic behavior of the shells as displayed in resonance curves.