Hybrid finite element method applied to the analysis of free vibration of a spherical shell filled with fluid

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.