Practical application of inverse boundary element method to sound field studies of tyres

摘要

The acoustic near field caused by tyre/road interaction has traditionally been studied with the aid of Near-field Acoustical Holography (NAH), allowing for a representation of the sound field on e.g. planar surfaces. This technique can be used to visualise the spatial character of the sound field radited by a tyre. A typical setup for Near-field Acoustical Holography consists of measuring the sound pressure on a plane surface close to the tyre sidewall and transforming this hologram into a picture of the sound field at the actual tyre surface. Assuming stationary conditions, the measurement can be done using a scanning technique. The entire procedure may be sufficient if the goal is to study tyrewall vibration or planar surfaces in general. On the other hand, a complete description of the vibrating tyre surface would be quite informative so that sources of vibration could be studied on the tread pattern. An approach based on boundary element modelling of sound sources and regularisation techniques was compared with Near-field Acoustical Hologrpahy in a study of vibration patterns on a rolling tyre.