Abstract

The performance of a road vehicle is directly related to the static and dynamic properties of tires, which provide support and control for vehicles and which must possess good durability under various tire-road interactions and loading conditions. The tire characteristics are inherently dependent on various structural and geometric parameters, the material properties of the individual layers of a tire and the loading conditions. In view of the simulation and analysis of tire response, in terms of deformation and stress fields, and vibration properties, extensive analytical studies had been conducted in the past based on the linear analysis of the multi-layered tire structure, assuming negligible shear interactions between the layers. In this dissertation, a nonlinear finite element model of a radial truck tire is developed based on its composite structural elements to analyze the various stress fields, with focus on the inter-ply shear stresses between the belt and carcass layers as functions of normal loads and inflation pressures. The model is validated through a comparison of the normal force-deflection characteristics and the contact patch geometry derived from the model with the laboratory-measured data in a qualitative sense. The tire model is used to conduct a parametric study on the shear interactions in the multiple layers under a wide range of loading conditions, to derive a more desirable set of structural parameters that can lead to lower values of maximum shear stresses within the loaded multi-layered tire structure. A polynomial function has been derived to estimate the two-dimensional tire-road contact pressure distribution as a function of the inflation pressure and the normal load. The tire model is further used to study the free-vibration behavior of the inflated tire structure. The influences of the individual structural parameters on the load and pressure-dependent natural frequencies of a radial truck tire are also investigated. The results show that the proposed finite element tire model based on adequately measured geometric and material properties of a tire structure can yield considerable benefits in the tire design and heavy vehicle performance.