Summary In this paper, we propose a numerical method based on an active structural control to dampen the discrete critical frequencies from a fe/be coupled system, which models a time‐harmonic fluid‐structure interaction problem. The active structural acoustic control used consists of applying external forces directly on the structure, so that in the presence of critical frequencies, the linear system remains stable and, in turn, in the presence of non‐critical frequencies, the active control does not alter the system. We consider the problem in the framework of the theory of optimal control and present bi‐dimensional numerical simulations to show the behavior of the scheme in some vibro‐acoustic structures. Copyright © 2016 John Wiley & Sons, Ltd.