High Frequency Dynamic Behaviour of Smooth and Patterned Passenger Car Tyres

Most traditional tyre models concern the low and middle frequency ranges. For improved accuracy in tyre/road interaction models it is necessary to include higher frequencies. Often only the radial direction is included, although the tangential direction may be important, especially studying stick slip motion in the contact between tyre and road surface. Designing accurate and efficient models requires insight into the behaviour of the tyre structure at higher frequencies to make the models as complete as necessary without creating tools that are computationally too costly. To add insight to this area, experimental studies were done on four different tyres with the same internal design but with different tread patterns. Point mobilities were measured and compared with two different tyre models, a two-layer plate model based on the elastic field equations and an orthotropic plate model. The results of this study underline the importance of the local deformation when there are forces that act with small excitation areas on the tread. Adequate consideration of the tread properties in the tyre/road interaction models is thus of extreme importance to obtain the correct local contact force distribution. This is most important for the tangential driving point mobility. Tread patterns are shown mainly to modify the flexural stiffness in comparison to smooth tyres, while block resonances are not expected to be located in the frequency range in which tyre/road noise is important.