Experimental Acoustic Modal Analysis of an Automotive Cabin

The interior sound perceived in an automobile cabin is a very important attribute in vehicle engineering. Therefore, an ever-increasing interest exists to predict the interior acoustic behavior by means of accurate simulation models both to improve the vehicle NVH performance and to reduce the devel...

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Bibliographic Details
Published in:Sound and Vibration 2015-05, Vol.49 (5), p.10
Main Authors: Accardo, Giampiero, Peeters, Bart, Bianciardi, Fabio, Janssens, Karl, El-kafafy, Mahmoud, Brandolisio, Daniele, Martarelli, Milena
Format: Magazinearticle
Language:English
Subjects:
Finite element analysis
Methods
Noise
Parameter estimation
Pressure distribution
Online Access:Get full text
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Summary:The interior sound perceived in an automobile cabin is a very important attribute in vehicle engineering. Therefore, an ever-increasing interest exists to predict the interior acoustic behavior by means of accurate simulation models both to improve the vehicle NVH performance and to reduce the development cycle of a new vehicle. Nevertheless, the current level of accuracy of such models is not sufficient to replace the design prototype phase with an all-digital phase. Experimental methods in which an acoustic characterization is performed play an important role in understanding the modeling challenges, improving the overall modeling know-how and providing a detailed comprehension of the physical behavior. Besides these these longer-term objectives, experimental acoustic methods are also instrumental as part of a vehicle development program and to refine the design; for example, troubleshooting booming noise. By means of a case study on a fully trimmed sedan car, this article discusses acoustic modal analysis equipment requirements and testing procedures. Due to specific challenges, such as high modal damping ratios and the need to use a large number of sound sources spread around the cabin to get a sufficient excitation of the modes, modal parameter estimation is often not a trivial task. The modal parameters (resonance frequencies, damping ratios, mode shapes, and modal participation factors) will be estimated from the measured frequency response functions by the new ML-MM method, a multiple-input, multiple-output frequency-domain maximum likelihood estimator based on a modal model formulation.
ISSN:1541-0161