This paper presents a coupled ES-FEM/FEM method for structural-acoustic problems, in which the ES-FEM and FEM models are used to simulate the structure and the fluid, respectively. In the present coupled models, the triangular Reissner-Mindlin plate element is adopted to model the flexible plate with the discrete shear gap (DSG) method for eliminating the transverse shear locking. The discretized equations for the plate are established by using the smoothed Galerkin weak form, and numerical integrations are performed based on the edge-based smoothing domains. The discretized equations of structural-acoustic problem are then derived by combining the ES-FEM for the structure and FEM for the acoustic fluid. The gradient smoothing technique used in the structure domain can provide proper softening effect, which will effectively relieve the well-known ''overly stiff'' behavior of the FEM model and thus improve the solution of coupled system. Numerical examples of the cylinder cavity of fluid attached to a flexible plate and a passenger compartment have been presented to show the effectiveness of the coupled ES-FEM/FEM for structural-acoustic problems.
Zhicheng He, Guirong Liu, Z. Zhong
Finite Elements in Analysis and Design