Unified meshfree-spectral BEM model for acoustic radiation analysis of double-walled coupled shells

Abstract

A unified mathematical model for acoustic radiation responses of laminated composite double-walled coupled shells with bulkheads immersed in an unbounded light and heavy fluid environments is established by utilizing unified meshfree-spectral BEM (boundary element method). In order to ensure the stability and reliability of the numerical solution, the mathematical model is divided into several hyperbolic curves, cylindrical shells and ring plates. Different types of the doubly-curved shell are considered such as elliptical and paraboloidal shells. By analyzing the geometrical relationship of double-walled shell, the displacement continuous boundary conditions between adjacent segment interfaces are determined. The structural field and external acoustic field of a double-walled shell are derived by using the energy principle in framework of first-order shear deformation theory and Kirchhoff-Helmholtz integral formulation respectively. The numerical example shows that the mathematical model can be used to solve the acoustic radiation response of the double-walled coupled shell in the acoustic fluid medium. Finally, the effects of representative parameters such as geometry, acoustic fluid medium, boundary conditions and external load on the acoustic radiation characteristics of double-walled shells are systematically discussed, which provides useful information for the design of light and heavy fluid double-walled structures.