Optimization of characteristics of porous materials based on a modal synthesis method

Complex structures used in the automotive industry often include porous materials, in order to reduce the noise in acoustic cavities. The method proposed in this paper aims at optimizing the characteristics of these porous materials using modal criteria based on the modal analysis of the structure. The use of a generalize modal synthesis method allow to describe the structure and the cavities with sets of modes; the size of the resulting system is smaller, for only generalized degrees of freedom are used for each part of the coupled fluid-structure system. First, a modelization of the porous media is proposed, and the generalized modal analysis method is explained. An optimization is then processed on the thickness of the porous materials.