Vibro-acuostic Analysis of Muti-Stepped Circular Cylindrical Shells Immersed in Fluid Medium

In this paper, a semi-analytical method for investigating the vibro-acoustic characteristics of multi-stepped cylindrical shells (MSCS) immersed in infinitefluid medium is presented.Based on the Flugge’s thin shell theory, the theoretical model for vibration analysis of MSCS is established, whereas acoustic analysis is carried out by employing theKirchhoff–Helmholtz integral equation. TheChebyshev polynomialsis set as shape function for vibro-acoustic analysis of the MSCS, all displacement components are expressed by the Chebyshev polynomials in meridional direction and Fourier series in circumferential direction. For discretizing of acoustic boundary, a set of Chebyshev collocation points and spectral boundary element are introduced, and for solving the non-uniqueness problem in acoustic analysis, the CHIEF method is applied. Through comparison studies with the results of previous literature andthe coupled finite element method/ boundary element method (FEM/BEM), the accuracy, convergence and reliability of the proposed method are verified. Finally, the effects of geometry, boundary conditions, fluid medium, material properties and type of applied force on the vibro-acoustic characteristics of MSCS are investigated by several numerical examples.