Application and extension of acoustic holography techniques for tire noise investigations

Abstract

Acoustic holography (AH) is a powerful measurement tool for the investigation of complex sound radiation problems. Enabling detailed source investigations based on noncontact measurements, it is especially useful for the investigation of rotating noise sources such as automotive tires. Nevertheless, conventional AH techniques are burdened by the constraint that the source is assumed to be planar. Based on a detailed measurement series which was performed on a laboratory roller bench, the radiation of a test tire was investigated by means of AH. It was found that even though valuable information could be obtained, the most important forward and backward radiation of the tire is difficult to tackle in this way. Another approach of the radiation analysis is offered by developing an inverse BEM method. Different implementations of the method have been worked out and tested, based mainly on the sysnoise and matlab software packages. The technique is applied to experimental tire mock-ups as well as to real-life tire measurements. The practical application and inherent limitations of the technique are also discussed.

Numerical Methods for Near-Field Acoustic Holography over Arbitrarily Shaped Surfaces

“…The indirect formulations are based on representations to the solution of Equation 1 like the single source or double source representation found in Augusztinovicz (1999); Delillo et al (2000); DeLillo et al (2001;; Raveendra et al (1998);Schuhmacher et al (2003); Tekatlian et al (1996); Vlahopoulos & Raveerdra (1998);Williams et al (2000); Zhang et al (2001;2000). Using the notation of the previous subsection the single source representation is defined as…”