Dependance of the contact area on the velocity of a rolling tire

ENPC, UR Navier, 6 et 8 Avenue Blaise Pascal, Cité Descartes, Champs sur Marne, 77455 Marne la Vallée, France, .
The Journal of the Acoustical Society of America (Impact Factor: 1.5). 06/2008; 123(5):3868. DOI: 10.1121/1.2935745
Source: PubMed


It is known that the eigenfrequencies of a rolling tire depend on the velocity of rotation. We distinguish two causes for the stiffness increase: the frequency dependence of the complex modulus of the materials and the geometrical stiffness. The real part of the Young's modulus is monotonic according to the frequency. It contributes for an important part to the stiffening. The geometrical stiffness also increases with the rotational velocity. A consequence of these effects is the modification of the size of the contact area for different velocities of a rolling tire. Here we first present experimental results estimating the size of the contact area for a tire in statics and for different rolling velocities. Differences of 20% can be observed. Then the viscoelastic behaviours of the tire materials are presented and experimental results showing the frequency dependence of the complex modulus of the tire constitutive materials are given. Then finite element computations are presented with a real distribution of materials in the tire section and the size of the contact area is estimated and compared to experimental measurements. These results could improve the modelling of tire road interaction for tire noise predictions.

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    ABSTRACT: This work gives a dynamical approach for periodic structures and the application to tire modellings. The static and dynamic properties of the constitutive materials of the tire have been measured. Some specific models of homogenization have been used to determinate the mechanical equivalent characteristics. The frequency response functions have been measured at several points on the tire in two cases of excitation force: on the tread belt and on the sidewalls. The dynamical theory of periodic structures is presented. A transformation into the cartesian reference system of the structures having the periodicity in the non-cartesian reference system has been suggested. The utilization of transformation in the case of tire ensures periodic conditions in the exploitation of the matrices of cells. The mobilities at several points of the tire have been calculated and compared with the measurement. This work allows in one side the dynamical studies of tire in the high frequency range and in the other side a parametrical study of the influence of the material properties and the tire inflation pressure.
    Full-text · Article · Jan 2008