Source Identification Using Nearfield Acoustic Holography Applied to a Seat Belt Retractor

Nearfield Acoustic Holography (NAH) can be used to identify the sources of intermittent contact. In this study, a seat belt retractor is exposed to a random vibration and the resulting noise is measured with an array of microphones. Acoustic ray back-tracing is used to determine the area distribution of surface velocities at the seat belt retractor and better understand the nature of the internal noise sources.