Vibration and damping analysis of thick sandwich cylindrical shells with a viscoelastic core under arbitrary boundary conditions

• A unified method is presented for thick sandwich cylindrical shells with a soft core.
• Multilayered sandwich shells under arbitrary boundary conditions are considered.
• Results for sandwich shells with elastic restraints are firstly presented.
• Effect of fiber orientation angle and thickness are thoroughly investigated.

An accurate solution approach based on the first-order shear deformation theory (FSDT) is developed for the free vibration and damping analysis of thick sandwich cylindrical shells with a viscoelastic core under arbitrary boundary conditions. Laminated and sandwich theories are employed to describe the laminated composite layers and viscoelastic material layer, respectively. The present solution is based on a set of new displacement field expression in which the displacements of the middle surface are expanded as a combination of a standard Fourier series and auxiliary functions. Due to the improved displacement expansions, rapid convergence and high accuracy can be easily obtained. The current method can be universally applicable to a variety of boundary conditions including all the classical cases, elastic restraints and their combinations. Natural frequencies and loss factors under various boundary conditions and lamination schemes are calculated, which may serve as benchmark solutions in the future. The effects of some key parameters including the boundary conditions, fiber orientation angle, and number and thickness of the layers on free vibration and damping characteristics of the shells are illustrated and analyzed.