An Overview of Acoustic and Structural Acoustic Simulations at Sandia National Laboratories

T.F. Walsh

Computational Solid Mechanics and Structural Dynamics
Sandia National Laboratories
P.O. Box 5800, MS 0380
Albuquerque, NM 87185
tfwalsh@sandia.gov


In this talk we will present an overview of acoustic and structural
acoustic simulations at Sandia. We will focus mainly on the numerical
algorithms, but a discussion of specific application areas of interest
will also be given. We will begin with an overview of the governing
partial differential equations, weak formulations, and finite element
implementations for acoustics and structural acoustics. Historically,
linear acoustic theory has been the most popular approach when
developing numerical methods for sound and vibration analysis. We will
discuss recent trends in using nonlinear acoustic formulations for
these problems, especially when the wave amplitudes involved become
large. Nonlinear acoustic formulations will be presented, along with a
formulation for coupling nonlinear acoustic equations with
small-deformation structural mechanics. For mismatched
acoustic-acoustic and structural-acoustic meshes, we will discuss an
approach for nonconformal mesh coupling, along with examples that
demonstrate its utility. The quadratic eigenvalue problem that results
from the vibration of coupled acoustic/solid systems will be
discussed. For the case of parallel computations, we will discuss the
decomposition strategy taken for coupled structural acoustic meshes,
and we will compare iterative linear solvers for both time and
frequency domain structural acoustics.

Several example problems will be presented. Sandia is a multi-program
laboratory operated under Sandia Corporation, a Lockheed Martin
Company, for the United States Department of Energy under Contract
DE-AC04-94-AL85000.