This paper presents the principle and a demonstrative application to a passenger car of new analysis procedures for investigating the interior noise characteristics of vehicles. In the first stage of the approach described, a finite element model of a car structure and an acoustical model of the internal cavity are combined to predict vibro-acoustic transfer functions using a modal superposition approach. Subsequently a panel contribution analysis can be performed in order to identify parts of the structure which may be critical in terms of the acoustic response inside the passenger compartment. The contribution of each mode separately is then determined in order to assist in the physical interpretation of the results.
As is demonstrated, an alternative to conducting a full numerical analysis is to follow a hybrid approach by using measured structural FRF’s together with the model of the cavity in order to determine the respective vibro-acoustic transfer functions.
The results, analysed and compared with direct measurements, establish the validity of these procedures and highlight their potential as part of the programme of development and optimisation of the vehicle structure.
