ABSTRACT
Air cavities in the tyre tread and the gap formed between tyre and pavement are excited during vehicle movement on a pavement. The former results in pipe resonance, and the latter results in horn resonance. These effects will be varying with speed of the vehicle and also because of conditions of tyre, pavement and, tyre-pavement interaction (TPI). The objective of this paper is to study the dynamic characteristics of air cavity resonances from the signals of the tyre-pavement interaction noise, which was collected by a pair of microphones, when a two wheeler is driven on a pavement at different speeds. The dynamic characteristics of the resonances are analysed using single frequency filtering (SFF) analysis of signals. The method gives spectral information at every sampling instant. The effects of impacts of the tyre treads, pavement characteristics, and TPI on the resulting cavity resonances are examined at four different vehicle speeds and for two different types of pavements. The analysis shows that the SFF spectra bring out the distinct characteristics of the pavements on the formation of air cavities and excitation of the resonances of these cavities. This analysis may help in determining the condition of the tyre and pavement.
ABSTRACT
The acoustic responses of a dynamical system reflect the characteristics of the external excitation and vibrating system. The objective in an identification problem is to characterise the system and excitation from the measured responses. This becomes challenging if the characteristics of the dynamical system are time-varying. The analysis of the acoustic signal generated as a result of the tyre-pavement interaction (TPI) is one such situation, where in order to study the time-varying nature there is a need to obtain the characteristics of the instantaneous response. This study explores the single frequency filtering analysis of signals to examine the time-varying characteristics of tyre-pavement interaction noise (TPIN). Field measurements of TPI acoustic signals were obtained for a two-wheeler driven at different speeds on asphalt and cement concrete pavements. The time-frequency characteristics of the tyre tread impact and of the air cavity resonances are analysed by investigating the effect of vehicular speed and pavement type on TPIN. The specific features of TPIN such as the harmonics due to periodic tread impact and the frequency response due to resonances of the air cavities are examined in detail. The analysis presented in this paper will be useful in developing methods for health monitoring of tyre and pavement systems.
