In this thesis, one proposes an approach allowing to enlarge the efficiency of SEA method (Statistical Energy Analysis). It is based on a dual modal formulation and a reformulation of SEA model without modal energy equipartition assumption. The dual modal formulation, which is presented in the general case of the coupling of three-dimensional continuous systems, consists of a non standard modal expansion, using a dual formulation stress - displacement. The modal equations are then in coherence with the model assumed by SEA and are characterized by modes of uncoupled subsystems. The SmEdA model derived from the SEA reformulation, permits to improve the quality of the prediction, especially when the modal overlap is low or when subsystems are locally excited. One of the interests of the present approach is that it can be easily included in a general SEA context. It is possible to apply SmEdA only for the subsystem couplings where an improvement can be presumed to be obtained, and to use classical SEA for the others subsystem couplings. The application of SmEdA model to industrial structures can be done thanks to finite elements models. It leads to a new technique to estimate SEA coupling loss factors when equipartition assumption is assumed. This approach only requires the subsystem mode calculation with finite elements method. Then, CLF are directly derived from identification of the coefficients of modal equations, without solving the vibratory problem.
