The 3D model of the structure is created in Ansys Design Modeler and meshed with solid elements. The structural bodies use SOLID185 elements. The acoustic cavities (sound port, air gap, and housing cavity) are modeled with FLUID30 elements. The air gap is meshed with a one element layer of SOLID226 electrostatic-structural elements (KEYOPT(1) = 1001) that use the elastic air option (KEYOPT(4) = 1). The Physics Region object is needed to scope and activate the respective physics definition as shown in the following image.
The fluid elements must be created on top of the airgap to account for vibroacoustic coupling. It can be done using the following commands:
