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

## 2aNSa2. Optimization techniques in structural acoustic design.

**Kenneth A. Cunefare
**

**
**
*George W. Woodruff School of Mech. Eng., Georgia Inst. of Technol.,
Atlanta, GA 30332-0405
*

*
*
This paper addresses optimization for the minimization of total radiated
acoustic power from practical three-dimensional structures. Optimization
techniques currently focus on developing coupled computational models for the
structural and acoustic responses, in terms of certain controllable design
variables. Typically, the computational tools for developing these models are
finite element and boundary element methods. For a given assumed excitation,
the coupled model is optimized to produce a minimum radiated power condition.
This approach is computationally intensive, due to the need to explicitly solve
for the total response at each design iteration. The recently developed concept
of ``exterior acoustic modes'' may provide a means to significantly reduce the
computational effort required for the acoustic portion of a response model, for
frequencies below some coincidence frequency criterion. The exterior modes
concept yields a greatly simplified objective function for total radiated
power, as compared to an objective function obtained through other means. This
paper discusses the current art, and presents the alternative approach using
the exterior modes representation. Optimization of the mass distribution of a
baffled finite plate is used as a benchmark problem.