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

Abstract

To cite this version:Sébastien Besset, Louis Jezequel. Optimization of characteristics of porous materials based on a modal synthesis method. AbstractComplex 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.

Acoustic absorption material optimisation in the mid–high frequency range

“…Let's mention the work conducted for years in the area of prediction in cavities [20][21][22][23][24]. More recently, authors have been focusing on simplified models [19] and the optimisation of structures coupled with acoustic cavities [25,26]. Energy methods are expected to offer many advantages.…”

A Reduction of the Equations of the Linear Stationary Vibrating Systems Without Limitations of Dissipation Using the Method of Modal Truncation

“…Other methods of elimination of high natural frequencies are obtained on the relevant reduction of the equations describing the vibrating system [6][7][8][9][10][11][12][13][14]. Among those methods, the method of modal truncation where the initial system of equations is divided to a number of independent equations is widely used; each of such independent equations describes modal vibrations of one natural frequency and then the equations corresponding to high natural frequencies are rejected (see, for example [10][11][12][13][14]). It is considered that the errors appearing in this case would be permissible, if the frequencies of the rejected modal vibrations are at least 1.5-2 times higher than the natural or resonance frequencies the investigator takes an interest in [15].…”