Analytical Tire Forces and Moments with Physical Parameters2
Abstract The pneumatic tire behaves as a highly nonlinear system. Its complexity has limited the development of a complete and reasonable theory governing its mechanics. Practical tire models used in vehicle dynamics simulation and tire-related research rely basically on curve-fitted experimental data and empirical adjustments of theoretical models. This paper introduces a validated analytical model based on the physical properties of the tire by formulating the shear contact phenomena with elliptical normal pressure distribution and planar stress-strain laws. Adjustments are introduced to current methods for estimating distributed stiffness, the use of friction, and the forces saturation phenomena. The analytical model is formulated and normalized to accept tire physical parameters that are easily estimated from force and moments measurements. These parameters are universal to all tires: lateral and longitudinal stiffnesses, aligning pneumatic trail, overturning effective moment arm, and frictional properties. The method of using fundamental mechanics for modeling contact patch forces and moments with tire physical parameters constitutes a significant advancement. The tire model is validated with experimental data.