Dynamic stiffness formulation and vibration analysis of coupled conical-ribbed cylindrical-conical shell structure with general boundary condition

In this paper, the dynamic stiffness method (DSM) is presented to investigate the vibration characterizes of coupled conical-ribbed cylindrical-conical shell structure with general boundary condition. Rib stiffeners are evenly distributed in the inner side of the cylindrical shell. Firstly, the coupled structure is divided into several components (i.e., conical and cylindrical shells, annular plate) according to the geometric properties and coupling boundary conditions. The displacement fields of the components are derived from the governing equations exactly. Then, the dynamic stiffness matrix is formulated based on the relationship between the displacements and forces on the boundaries of the components. The global dynamic stiffness matrix of the coupled structure is assembled in a similar way as used in the finite element method (FEM). In addition, the experimental model of conical-ribbed cylindrical-conical shell structure is built and vibration test is conducted. The accuracy and stability of the present method are validated by comparing the present results with the results obtained by FEM and experimental test. Several numerical examples are conducted to understand the effects of geometric parameters on the dynamic behaviors of the coupled structure, which can offer positive guides for acoustic design of the combined shell structure.

Automated summary

The dynamic stiffness method (DSM) is proposed to investigate the vibration characteristics of coupled conical-ribbed cylindrical-conical shell structures. The method divides the structure into components and formulates a dynamic stiffness matrix based on the relationships between displacements and forces. Experimental validation and numerical examples demonstrate the accuracy and stability of the method, providing insights into the effects of geometric parameters on dynamic behaviors.