Dynamic analysis of spherical shell partially filled with fluid

• An original formulation of hybrid finite element method was given in our paper
• The frequency of fluid filled shell decreases with shell radius to thickness ratio.
• The frequency drops significantly with height of fluid to shell radius ratio.
• The boundary conditions and geometries affect the behavior of fluid filled shell.

In present study, a hybrid finite element method is applied to investigate the free vibration of spherical shell filled with fluid. The structural model is based on a combination of thin shell theory and the classical finite element method. 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 are obtained and compared with existing experimental and theoretical results. The dynamic behavior for different shell geometries, filling ratios and boundary conditions with different radius to thickness ratios is summarized. This proposed hybrid finite element method can be used efficiently for analyzing the dynamic behavior of aerospace structures at less computational cost than other commercial FEM software.