Sensitivity analysis of coupled structural-acoustic problems using perturbation techniques

The analysis of acoustic radiation and scattering from submerged elastic structures is an important and challenging problem. Often, numerical solutions are hampered by the fact that the acoustic pressure field can be very sensitive to structural detail. In this paper, a procedure for obtaining the sensitivity of a structural-acoustic system to structural perturbations is presented. The theoretical development assumes a finite element description of the structure and a boundary element description of the fluid. The analysis includes full coupling between the fluid and the structure, and can accommodate both internal and/or external fluid regions. The types of perturbations are limited to those that do not alter the geometry of the wetted surface, but are otherwise completely general in nature. The technique is then applied to acoustic scattering from a cylindrical shell. Two perturbations are considered: A change in the shell thickness and a change in the elastic modulus. The effect of these structural per...