The effect of static loading and imperfections on the nonlinear vibrations of laminated cylindrical shells

The effect of static loading and imperfections on the nonlinear vibration behaviour of cylindrical shells is studied. The two analytical–numerical models (denoted as Level-1 and Level-2 Analysis) that are used for this purpose are based on Donnell-type governing equations and have different levels of complexity. Parametric studies have been performed for a specific laminated shell. The axial compressive loading and different imperfection shapes can significantly influence the linearized vibration behaviour and also affect the nonlinear vibration behaviour. Results show that certain axisymmetric imperfections, satisfying a strong-coupling condition with the asymmetric vibration mode, reduce the linearized vibration frequencies and make the nonlinearity less softening, while the static compressive axial loading makes the nonlinearity more softening.