Applications of the Statistical Energy Analysis to Vibro-Acoustic Modeling of Vehicles

In recent years, SEA has been recognized as an important tool to model the vibro-acoustic behavior of vehicles in mid and high frequencies. Through SEA it is possible to develop vehicle models early in the design stage, reducing the risk of future noise problems and allowing the optimization of noise control treatments. Moreover, at the final design stages, a SEA model can be use to evaluate changes at the project, reducing costs with experiments. In a SEA model, the structure under study is divided in subsystems. The capacity of each subsystem of storekeeping, dissipating and transmitting energy is described by three parameters: modal density, loss factor and coupling loss factor. The noise and vibration sources are include in the model as power inputs to subsystem and, based on an equilibrium power balance, it is possible to calculate the energy of each subsystem. The results obtained by SEA models should be interpreted as average values in time, in the frequency band, in space and at an ensemble of random structures. In this work, the applications of SEA at the vibro-acoustic modeling of vehicles are discussed. The details that should be observed when defining the structural and acoustic subsystem are pointed out. The main methods for the determinations of the SEA parameters are introduced. Special emphasis is given to the calculation of the power inputs of the main noise and vibration sources in a vehicle. Finally, some practical applications of SEA at the automotive industry are presented and discussed.