A 2D BEM–FEM approach for time harmonic fluid–structure interaction analysis of thin elastic bodies

This paper deals with two-dimensional time harmonic fluid–structure interaction problems when the fluid is at rest, and the elastic bodies have small thicknesses. A BEM–FEM numerical approach is used, where the BEM is applied to the fluid, and the structural FEM is applied to the thin elastic bodies. From the fluid point of view, the thin elastic bodies are considered of null thickness. This assumption is treated using simultaneously the Singular Boundary Integral Equation and the Hypersingular Boundary Integral Equation. It is assumed that the thin elastic bodies are under the Euler–Bernoulli hypotheses with added rotational inertia. The BEM equations (fluid) and the FEM equations (thin bodies) are coupled using appropriate equilibrium and compatibility conditions. The developed BEM–FEM model requires a simple discretization and leads to a small number of degrees of freedom, although it has some limitations that are studied in some depth. This approach is validated with existing results in the field of sound barriers, and new results using complex barrier shapes are presented. Also, a parametric study about a straight wall immersed in a fluid is done, which provides results of practical usage.