A Coupled Tire Structure-Acoustic Cavity Model

Abstract

Recent experimental results have shown that the vibration induced by the tire air
cavity resonance is transmitted into the vehicle cabin and may be responsible for significant
interior noise. The tire acoustic cavity is excited by the road surface through the contact
patch on the rotating tire. The effect of the cavity resonance is that results in significant
forces developed at the vehicle’s spindle, which in turn drives the vehicle’s interior acoustic
field. This tire-cavity interaction phenomenon is analytically investigated by modeling the
fully coupled tire-cavity systems. The tire is modeled as an annular shell structure in contact
with the road surface. The rotating contact patch or a harmonic point force is used as a
forcing function in the coupled tire-cavity governing equation of motion. The contact patch is
defined as a prescribed deformation that in turn is expanded in its Fourier components. The
response of the tire is then separated into static and dynamic components. The coupled
system of equations is then solved in closed form in order to obtain the tire acoustic and
structural responses. The influence of the acoustic cavity resonance on the spindles forces is
shown to be very important. Therefore, the tire cavity resonance effect must be reduced in
order to control the tire contribution to the vehicle interior noise. The modeling and analysis
of an approach to control the tire acoustic cavity resonances is investigated. The approach
consists in the incorporation of secondary acoustic cavities to detune and damp out the main
tire cavity resonance. The model is used to show that the secondary cavities are effective at
suppressing the tire cavity resonance and thus the forces at the spindle.