Is it possible to treat confidentially SEA the wolf in sheep's clothing?

Abstract

At present, Statistical Energy Analysis (SEA) is the most acknowledged tool for the solution of high-frequency problems. However, a reliable solution can be obtained by SEA only if particular conditions are satisfied. In other words, the basic hypotheses would define the range of applicability of this method. Two important parameters, coupling loss factor (CLF) and internal loss factor (ILF), play a key role in describing the power transmitted between subsystems and the power dissipated by each of them. The coefficients of the SEA equations depend on these parameters, while the known terms are the powers injected into each subsystem. Theoretical relationships allow to predict the CLFs and ILFs of simple subsystems, but very often the theoretical estimate of these parameters is incorrect and their values may be rather obtained experimentally. The aim of this paper is addressed to analyse whether a particular vibroacoustic problem can be efficiently solved by SEA. This is an initial attempt to provide the SEA user with a simple tool indicating if a SEA model can provide a significant result for the particular problem under study. The basic hypotheses involving the SEA parameters are systematically presented and translated into mathematical relationships to provide such tool. To check the validity of this approach two cases are analysed. First, a simple vibroacoustic problem, where the SEA parameters are theoretically determined, is studied. Then a more complex system, the case of three coupled plates is considered: the energy in the system is experimentally determined. Such result is then compared with the results of the SEA model: it is shown that, whenever the comparison is good or not, the mathematical hypotheses of SEA provide a significant a priori evaluation of the SEA efficiency.