A dynamic model and vibration characteristic analysis of damping gel-filled composite honeycomb cylindrical shells

Aiming at the deficiencies of existing models in predicting the vibration characteristics of filled honeycomb sandwich cylindrical shells, in this study, dynamic modeling and vibration characteristic analysis of damping gel-filled composite honeycomb cylindrical shells (DG-FHCSs) are performed, in which fiber-reinforced skins and a honeycomb core filled with a novel carbon nanotube-reinforced damping gel are designed and fabricated. Firstly, an analytical model for a DG-FHCS subjected to base excitation is proposed using the first-order shear deformation theory, virtual spring method, Rayleigh-Ritz method, modal superposition principle, and equivalent filling theory. The convergence analysis of the studied model is further conducted to determine the optimal truncation number for the polynomial, as well as the appropriate stiffness value for the virtual artificial spring. The results of the experiments and theoretical models demonstrate that the dynamic model developed in this study is capable of accurately predicting both the natural frequencies and resonance responses of the structure, as well as the vibration damping performance of the damping gel. Finally, the influence of key geometric and material parameters on the natural frequencies and resonance responses of the DG-FHCSs is investigated. The results indicate that appropriately increasing the honeycomb wall length, the ratio of honeycomb core thickness to fiber-reinforced skin thickness, and the honeycomb wall thickness can significantly improve the vibration suppression capabilities of the DG-FHCSs. The modeling and solving techniques, preparation procedures, testing methods, and conclusions drawn from this study provide important support for the applications in aerospace engineering, pressure vessel design, and related fields of the DG-FHCSs.