The main subject of this article is the verification of some theories of smart materials type feedback control, mainly by applications of piezo-elastic patches. The theory exists for the implementation of such controls which include a linear-quadratic compensation in the infinite-dimensional setting of distributed parameters theory. A rather delicate step consists of finding a “good” finite-dimensional approximation, such as a Ritz-Galerkian one, to come up with reliable computations. The convergence problems according to the authors have been almost completely solved. In particular, preservation of exponential stabilization and the convergence to optimal quantities has been extensively investigated by the authors and the Virginia group (Lasiecka, Lagnese, and their students). The authors state that the present article contains no new theoretical results, but describes in detail an experimental verification of much of this existing theory. Using PDE-based controllers, the authors check the reduction of vibration amplitudes, particularly of the transient effects, caused by a hammer impact. The subject of these tests is a vibrating circular thin plate. The mathematical model is fairly standard, but allowance is made for some non-uniformities and for discontinuities caused by attached piezo-elastic patches. The authors stress that the most important part of the procedure is to find a PDE model that describes with reasonable accuracy the physics of the process and the effects of the controls. The advantages of the correct mathematical setting (appropriate functional analytic space, use of the weak form of the equations of state) are in the authors opinion essential to the success of subsequent numerical analysis. As a consequence of the tests described in this article, the authors are convinced of the effectiveness of their use of PDE controllers. In particular, the results obtained for transient responses seem to be satisfactory.