Experimental sound source reconstruction using iPTF method: conformal mapping, FE model correlation and contributions by parts
Résumé
With the ambitious objective of reducing the cars weight and their cost, combined to the more and more stringent noise emission standards, the passive noise reduction solutions such as acoustic covers have achieved their limits. The design optimisation is currently a promising way to meet these new NVH challenges. In this context, the experimental sound source identification and characterization method like the m-iPTF method presented here may be an efficient tool and analysis support. Indeed, this method is able to reconstruct sound quantities directly on the real geometry of the structure and from only cost-effective pressure measurements performed in a possible complex industrial environment (noisy and/or cluttered). This conformal mapping makes possible sub-systems ranking and a precise identification of sound source to determine where local design changes have to be made to improve the overall noise radiation. In a context of reducing expensive prototypes and time development, it also allows an efficient comparison and coupling with numerical simulation in order to promote its development and its use (predictability and reliability of models). This article firstly reminds the basic theoretical framework of the m-iPTF method before illustrating its capabilities on a reduced engine block excited by an electro-dynamic shaker.