Identification of Tire Noise Generation Mechanisms Using a Roadwheel Facility

Abstract

In a study of tire noise generation mechanisms designed as a foundation for developing quieter tire designs, a series of acoustic and vibration measurements was conducted on four heavy-truck tires, utilizing a roadwheel facility enclosed in a semianechoic chamber. Data were recorded from five near-field microphones and from five accelerometers mounted inside the tires. Acoustic time signatures were analyzed to identify noise source locations and possible causes. Supporting tread void compression and other tire properties were measured. Excellent agreement was found between air pumping theory and measurements for a crossbar tire. Air pumping for a crossbar tire was found to be the dominant vibration generation mechanism. Air pumping for a rib tire was found to be a possible mechanism. Measurement of vibration on a running tire demonstrated the comparability of vibration levels in the sidewall and in the tread area. Vibration levels were higher in areas following the contact patch than in those preceding. If carcass vibration is a major noise generation mechanism, the sidewall would be as important a radiator as the tread area. A series of stationary vibration tests is planned to define the vibration response of the test tires (Green's function, modal properties, wave speed, resonances, and damping factors).