The airborne noise attenuation performance of sound package components can be conveniently simulated by the transfer matrix approach, for the frequency range where airborne noise transmission in vehicles is dominating. The simulation results can also be very accurate, both for the transmission and absorption characteristics, if many types of non-homogeneity of the components are taken into account. These include thickness variation of the decoupler materials and the variations of the physical properties of the porous materials (porosity, air-flow resistivity, stiffness, loss factor), which may come along with the thickness variation. The dependency of the porous materials parameters on thickness and density need to be determined experimentally. The Rieter Automotive VECTOR system includes a set of measurement systems for the determination of the involved material parameters. The results of these measurements are consistently stored in corresponding databases of the material properties. The transfer matrix simulation tool “SISAB”, also embedded in the VECTOR system, can extract these properties effectively allowing so to predict the acoustical quantities such as transmission loss and absorption of the components including the representation of their non-homogeneity. In the process of designing the sound package components it is then useful to have indications about the material parameters and material combinations, which provide the maximum possible absorption or insulation, for given thickness and area weight. This search for the optimal conditions can be performed either by systematic parameter variations, or by using the Genetic Algorithms approach, interfaced with the SISAB simulation tool. The first approach has the advantage of visualising parameter sensitivities whereas the second approach is far more computational efficient. Once the sound package components have been optimised in terms of absorption and insulation properties, their effectiveness in their vehicle installation can be foreseen by means of SEA models. These different steps are described in this paper.
Optimal design of a sound package component within the Rieter Automotive VECTOR system / K. Misaji; T. Yamashita; H. Tada; N. Baldanzini; H. Patzold; M. Mantovani. - STAMPA. - (2003), pp. 1-27. (Intervento presentato al convegno Rieter Automotive Conference 2003 tenutosi a Luzern, Svizzera nel 4-6 giugno 2003).
Optimal design of a sound package component within the Rieter Automotive VECTOR system
BALDANZINI, NICCOLO';
2003
Abstract
The airborne noise attenuation performance of sound package components can be conveniently simulated by the transfer matrix approach, for the frequency range where airborne noise transmission in vehicles is dominating. The simulation results can also be very accurate, both for the transmission and absorption characteristics, if many types of non-homogeneity of the components are taken into account. These include thickness variation of the decoupler materials and the variations of the physical properties of the porous materials (porosity, air-flow resistivity, stiffness, loss factor), which may come along with the thickness variation. The dependency of the porous materials parameters on thickness and density need to be determined experimentally. The Rieter Automotive VECTOR system includes a set of measurement systems for the determination of the involved material parameters. The results of these measurements are consistently stored in corresponding databases of the material properties. The transfer matrix simulation tool “SISAB”, also embedded in the VECTOR system, can extract these properties effectively allowing so to predict the acoustical quantities such as transmission loss and absorption of the components including the representation of their non-homogeneity. In the process of designing the sound package components it is then useful to have indications about the material parameters and material combinations, which provide the maximum possible absorption or insulation, for given thickness and area weight. This search for the optimal conditions can be performed either by systematic parameter variations, or by using the Genetic Algorithms approach, interfaced with the SISAB simulation tool. The first approach has the advantage of visualising parameter sensitivities whereas the second approach is far more computational efficient. Once the sound package components have been optimised in terms of absorption and insulation properties, their effectiveness in their vehicle installation can be foreseen by means of SEA models. These different steps are described in this paper.
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