A Semi-Analytical Method for Vibration and Buckling Analysis of Composite Laminated Cylindrical Shells Under External Hydrostatic Pressure

A semi-analytical method is applied to analyze the dynamic response of submerged medium-thick composite laminated cylindrical shells with significantly different mechanical properties under external hydrostatic pressure. The structural dynamical model is established by the energy principle, in which each shell layer follows the first-order shear deformation theory (FSDT) and the displacement continuity between layers satisfies the Layerwise theory. The axial partitioning technique is also employed to divide the structure into equal-sized segments, enhancing computational accuracy. The Chebyshev polynomials and modified Fourier series are applied to describe the displacement of shells. Considering the external fluid, the acoustic–vibration coupling effect between the radiated sound pressure and the vibration of the shell is determined by the spectral boundary element method. The hydrostatic pressure of the fluid is defined as the lateral pressure. The correlation between natural frequency and external pressure enables a nondestructive estimation of critical buckling pressure. Validation against published results and finite element analyses confirms the method’s accuracy. The main contribution of this study is the development of a refined analytical framework that captures the vibration properties of homogeneous, composite laminated cylindrical shells with different boundary constraints and structural parameters subjected to external hydrostatic pressures. Results demonstrate that composite shells offer superior dynamic stability and pressure resistance compared to homogeneous shells. Notably, when the middle-to-outer layer thickness ratio ([Formula: see text] exceeds 2, the composite shells exhibit better structural stability and anti-pressure ability with reduced structural weight. This study can also offer crucial guidance for the vibro-acoustic analysis, buckling pressure prediction of submerged structures and lay a foundation for future applications in submerged vehicle design.