Design and construction of an acoustic measuring device to investigate automotive tyre noise

Tyre noise measuring procedures are used worldwide and covered by appropriate International Standards, but from the literature search and the author's 30 years' expertise in acoustics, it became clear that there are still problems to overcome. The objective of this project is to design and construct a prototype stationary acoustic device that can produce and measure the noise emitted by the grooves and treads of automotive tyres and develop a new acoustic tyre measuring procedure. Through this new procedure, the noise measurement can be performed in a controlled laboratory environment, no expensive measuring platforms are needed, the cost of the tyre developers will be kept to a minimum, different models or a portion of the tyres can be used (even before tyre production starts), the tyres can be "noise classified" by public authorities, and the procedure will be isolated from the varying surfaces, e.g. roughness and porosity of the road pavement. The constructed apparatus / device is an open platform, and by using this procedure and methodology, research and many investigations can be performed in the future, to suit each investigator's objectives, both in tyre design and in pavement design. In the second stage of the thesis, it was necessary to compare the measured noise from the developed device with an actual rolling tyre, measured according to standard procedures. So a towed one wheel trailer, installed with microphones, has been constructed and tested. Validation of the trailer's noise data has been established conducting a further literature search and has proven satisfactory. In the third stage of the thesis, the main platform of the device was used to investigate further, more tyre related acoustic phenomena. Keywords: Tyre, road, acoustics, noise, measurement, spectral analysis, sound level meter, CPX trailer, pass-by, pavement interaction, porosity, texture, roughness, horn effect, noise regeneration.