Control of structural-acoustic radiation from tires by structural modification

Kiho Yum, Purdue University


The objective of this research was to reduce sound radiation resulting from a tire's structural vibration by modification of its orthotropic material parameters and tire shape. First, the structural wave propagation characteristics on a treadband were studied by using orthotropic shell theory and wave number decomposition and then tire surface vibration was investigated empirically and analytically. The effect of various tire material parameters on structural wave propagation and the associated sound radiation was estimated. Second, the sound radiation resulting from the structural vibration of a tire in contact with the ground was investigated by using BE analysis and experiment. In particular, the orthogonal radiation modes of a tire in the presence of a reflecting surface were calculated by applying an eigenvector analysis to the tire's radiation resistance matrix. Based on these analyses, the relationship between the structural wave propagation characteristics of a tire and its sound radiation was estimated. In addition, the effect of actual porous pavements and tire shape on sound radiation was studied. A strategy for reducing the radiated sound levels by modifying the tire parameters from a base set was determined. Finally an optimized set of tire parameters and tire shape that reduced noise emission was suggested. It was found that all structural vibration does not contribute to the sound radiation from a tire. The significance of the fast, longitudinal wave mode propagating through the treadband was confirmed by the large contribution of the modified ring radiation mode to the radiated sound power at the tire's ring frequency. The third radiation mode above 800 Hz is principally responsible for the horn effect in the presence of reflecting surface. The reduction of radiated sound below 800 Hz was achieved by an increase of treadband circumferential stiffness that was found to move the onset of longitudinal wave motion within the treadband into a higher frequency region. Secondly, flexural wave propagation was found to be mainly controlled by inflation pressure, cross-sectional treadband stiffness and cross-sectional length. By appropriate adjustment of these four parameters, it was found possible to substantially reduce sound radiation in a mid-frequency region.




Bolton, Purdue University.

Subject Area

Mechanical engineering

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