1.7.2 Coupling of acoustic and structural elements

Product: ABAQUS/Standard  

Elements tested

ASI1    ASI2    ASI2A    ASI3    ASI3A    ASI4    ASI8   

Problem description

The model consists of a column of fluid 100 units high with a cross-sectional area of 400. The fluid column is modeled with five acoustic elements; five high and one in the cross-section. The top of the column has a zero pressure boundary condition applied, thus representing a free surface. The base of the column is connected to structural degrees of freedom via an acoustic-structural interface element.

A dynamic analysis is performed during which a sinusoidal acceleration is applied to the base of the fluid column via the interface element. The pressure distribution throughout the fluid column is determined after one unit of dynamic time has elapsed.

Material:

Bulk modulus2 × 109
Density1000.0

Acoustic link element model:


Link length20.0
Link area400.0

Two-dimensional acoustic element model:


Acoustic element size20.0 × 20.0
Element thickness20.0

Axisymmetric acoustic element model:


Acoustic element size11.28379 × 20.0

Three-dimensional acoustic element model:


Acoustic element dimensions20.0 × 20.0 × 20.0

Results and discussion

at node 1 is the same for all tests.

Input files

ei11aca1.inp

ASI1, AC1D2 elements.

ei11aca2.inp

ASI1, AC1D3 elements.

ei22aca1.inp

ASI2, AC2D4 elements.

eia2aca1.inp

ASI2A, ACAX4 elements.

ei23aca2.inp

ASI3, AC2D8 elements.

eia3aca2.inp

ASI3A, ACAX8 elements.

ei34aca1.inp

ASI4, AC3D8 elements.

ei38aca2.inp

ASI8, AC3D20 elements.