Hydroelastic vibration of partially liquid-filled circular cylindrical shells under combined internal pressure and axial compression

In the present study, a hybrid finite element method is applied to investigate the dynamic stability of a partially fluid-filled circular cylindrical shell under constant lateral pressure and compressive load. The structural formulation is a combination of Sanders shell theory and the classic finite element method. Nodal displacements are derived from exact solution of Sanders shell theory. Initial stress stiffness in the presence of shell lateral pressure and axial compression are taken into account. It is assumed that the fluid is incompressible and has no free-surface effect. Fluid is considered as a velocity potential variable at each node of the shell element where its motion is expressed in terms of nodal elastic displacement at the fluid-structure interface. Numerical simulation is done and vibration frequencies for different filling ratios of pre-stressed cylindrical shells are obtained and compared with existing experimental and theoretical results. The stability for different shell geometries, filling ratios and boundary conditions with different combinations of lateral pressure and axial compression is summarized. This proposed hybrid finite element method can be used effectively for analyzing the dynamic stability of aerospace structures at less computational cost than other commercial FEM software.