Free vibration analysis of joined doubly-curved shells of revolution

Aiming at the problem that the analysis method of free vibration characteristics of double-curvature composite structures needs to be improved, the free vibration characteristics of double-curvature composite shell structures are investigated based on a semi-analytical method. Based on Flügge's thin shell theory, the double-curvature composite shell structures are firstly divided into substructures of paraboloidal, cylindrical and spherical shells at the interface. Secondly, the paraboloidal, spherical and cylindrical shells are further divided into several shell segments along the radial direction, the displacement functions of each shell segment are represented by Jacobi polynomials along the axis direction and the Fourier series along the radial direction, and the continuous conditions at the interface and the boundary conditions at the two ends of the composite shells are modeled using different spring stiffness. Finally, the free vibration frequencies of double-curvature composite shell are obtained based on Rayleigh-Ritz method. To test the convergence, validity and accuracy of present method, numerical results are compared with those obtained using the FEM and existing literatures, and very good agreement is observed. The results of this paper can provide a judging method and reference data for free vibration characteristics of double-curvature composite shell with complex boundary conditions. © 2020, Nanjing Univ. of Aeronautics an Astronautics. All right reserved.