The tire air cavity mode is known to be a significant source of vehicle structure-borne road noise near 200 Hz. A porous lining placed on the inner surface of a tire is an effective countermeasure to attenuate that resonance. The two noticeable effects of such a lining are the reduction in the cavity resonance frequency and the attenuation of the air cavity mode. In this paper, through both theoretical and numerical analysis, the mechanisms underlyiing the effects of a porous lining were studied. A two-dimensional duct-shaped theoretical model and a torus-shaped numerical model were created to investigate the lined tire in conjunction with the Johnson-Champoux-Allard model describing the viscous and thermal dissipative effects of the porous material. Design parameters of the porous lining were varied to study their impact and optimal ranges of the design parameters were identified. Finally, in an experimental analysis, the sound attenuation and the frequency drop were observed in measurements of force, acceleration, and sound pressure. In conclusion, it was demonstrated that the suggested theoretical and numerical models successfully predict the effects of porous linings and that the frequency reduction results from the decreased sound speed within the tire owing to the presence of the liner.
Tire noise, Acoustic cavity mode, Foam lining, Lining optimization, Flow resistivity
Acoustics and Noise Control
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