### ASA 127th Meeting M.I.T. 1994 June 6-10

## 5pSA1. Effect of different boundary conditions in the finite element
modeling of acoustic field problems involving infinite domains---An application
to smart structures.

**Vasundara V. Varadan
**

**
Jaehwan Kim
**

**
Vijay K. Varadan
**

**
**
*Res. Ctr. for the Eng. of Elect. and Acoust. Mater., Dept. of Eng. Sci.
and Mech., Penn State Univ., University Park, PA 16802
*

*
*
In the modeling of structural acoustic problems involving infinite
domains, finite element modeling is often used in regions involving complex
geometry, material anisotropy, coupled fields, etc. These same problems often
involve coupling of the structure with an infinite acoustic fluid. Several
methods have been proposed involving infinite elements, Dtn boundary
conditions, matching the FEM representation with analytical representations in
the infinite domain, to name a few. In modeling the response of embedded
sensors and actuators in a structure subject to fluid loading, we have found it
convenient to match plane wave solutions in the acoustic fluid with the FEM
representation. The matching can be done with and without slope constraints and
the matching can also be done using the so-called Dtn (Dirichlet to Neumann)
boundary condition that results from the radiation conditions in the infinite
domain. A parametric study of convergence and accuracy of numerical results
using each of these methods will be presented.