Inverse problems in transient structural acoustics

Abstract

Inverse problems are frequently encountered in transient structural acoustics. Given measured accelerometer or microphone time histories, one may need to estimate material properties in a structure, impedance conditions on the boundaries, shape or topology of an object, or characterize acoustic and structural sources that produced the measured data. Applications include model calibration, acoustic testing of aerospace structures, military surveillance, and underwater acoustics. Typically, accelerometer or microphone pressures are measured experimentally, and it is desired to characterize the material parameters, boundary conditions, topology, or acoustic sources that produced these accelerations or microphone pressures. In this talk, we will present a set of example inverse problems in structural acoustics, and a framework for their solution using an operator-based partial differential equation (PDE) constrained optimization approach. This abstract framework enables one to reduce any inverse problem to a set of fundamental operations and enables re-use of several software constructs. Formulations will be presented in both the time and frequency domain, and the merits and drawbacks of both approaches will be discussed. [Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL850000.]