Inverse parametric optimization method for the characterization of the acoustic field radiated by a rail with a microphone array - Experimental validation with a modal shaker
FAURE ; CHIELLO ; PALLAS ; SERVIERE
Type de document
COMMUNICATION AVEC ACTES INTERNATIONAL (ACTI)
Langue
anglais
Auteur
FAURE ; CHIELLO ; PALLAS ; SERVIERE
Résumé / Abstract
For speeds up to 300 km/h, rolling noise is the main railway noise source. It arises from the acoustic radiation of various elements such as wheels, rails or sleepers. The rail, which mainly contributes to rolling noise at midfrequencies and dominates from approximately 500 Hz to 1000 Hz, is an extended coherent source for which classical array processing methods are inappropriate to noise source identification. The properties of the acoustic field radiated by the rail are heterogeneous with regard to space and frequency, and depend on the vibration waves that propagate along the rail through the structural wavenumbers. In this paper, an inverse parametric optimization method is proposed to characterize the acoustic field radiated by a rail from microphone array measurements. The unknown parameters of a vibro-acoustical model (amplitudes and complex wavenumbers) are estimated through the minimization of a least squares criterion applied to the measured and modelled spectral matrices of the array. First, simulations are performed in order to appraise the performance of the method, in the case of vertical point excitations on the rail. This simple case is then validated experimentally for a single vertical point excitation using a modal shaker and a horizontal linear array.
Editeur
Société Française d'Acoustique -SFA ; Institute of Acoustics -IOA
