Prediction and Simulation of Tire Performance using "Deformation Index"

Tires serve important functions in the performance of a car: supporting load, transferring forces in driving, braking, and steering under all weather conditions.    A tire should perform all these functions with minimum energy loss for fuel economy and good wear resistance.     Hysteretic energy loss of tread compounds has been considered important for tire performance of traction, rolling resistance, and wear resistance.   Loss factor, Tan delta, is most often used as dynamic viscoelastic property for the energy loss.    However, dynamic modulus can also contribute positively or negatively to the energy loss depending on the type of deformations.    The concept of "Deformation Index" has been proposed to define the type of deformation and relevant dynamic property relating to each performance.   The deformation index of tread compound has been experimentally determined for rolling resistance, wet and dry traction of passenger tire.    In this talk we show that the concept can be extended to FEA analysis to simplify the computational process of the rolling resistance and thermo-mechanical analysis of a rolling tire.   Two examples of its application will be shown: optimization of rolling resistance involving all tire components and simulation of transient temperature development in a rolling tire.