DIRECT AND FLANKING SOUND TRANSMISSIONS IN ENCLOSURES FOR SEPARATING WALLS MOUNTED ON ELASTIC JOINTS AT LOW FREQUENCIES

摘要

A general method is proposed to investigate the vibroacoustic behavior of complex structures coupled to an acoustic cavity at low frequencies. A finite element description is used for structural displacements and fluid pressure fields. The coupled forced system is expanded on the uncoupled structure and rigid cavity modal basis. The structural modal analysis is performed using a free-interface component mode synthesis technique. The method proves to be accurate and adapted to parameter studies on structural complexities. In this paper, it is shown how the method can be used to investigate the direct and flanking sound transmissions in the case of a partition coupled to a cavity with flexible walls. In addition, a general elastic joint between the separating wall and the lateral walls is accounted for in the model. In order to consider this mass-less joint as a substructure in the component mode synthesis, the original free-interface technique has been modified both in the definition of the attachment modes and in the assembly procedure. The resulting predicting method allows for an efficient calculation of vibroacoustic indicators for different mechanical joint properties. Finally, original results on structural-acoustic transmission paths are presented and discussed.