Influence of mechanical wear on tyre noise

Tyre wear state is an important considerations from safety point of view, since it a ects passenger comfort and noise levels. The noise signature changes significantly due to mechanical wear and chemical ageing during its lifetime when it encounters the road surface. These noise can be further categorized to low (structure - borne) and relatively high frequency (e.g., approximately 800 Hz and above). This article details the drum test rig results which allows the reproducible measurements of tyre road noise on real road surfaces at speeds up to 120 km/h. To analyze the wear state of a passenger car tyre, at first the acceleration/vibration data of the tyre tread of varying non skid depth (NSD) is recorded by an acceleration sensor. The time-series waveform of acceleration at leading, center and trailing edge region is then extracted to frequency domain by using the well known Fast Fourier Transform (FFT) technique. The vertical mode frequency data and the noise signals of worn out tyre is analyzed. Finally, the e ects and mechanisms of the noise phenomena are discussed and it is concluded that tyre noise can be quantified in advance for a particular tread pattern if tyre ageing is ignored.