In this study, slip ratio of the tire is analyzed using dynamic finite element analysis of the elastic disk model of the tire. The elastic disk composed of three parts(hub, foundation, ring) on rigid ground. The contact elements are laid between the disk and the ground to obtain contact status and force distribution in the contact patch.
The slip ratio is originally defined in the vehicle dynamics studies by the relation of the velocity of the tire axle and angular velocity of the tire. It is also known from analytical study that the slip ratio is proportional to the ratio of sliding region area to total contact patch area up to the point when the slip ratio reaches the maximum value. When the tire is in transient state such as tractive torque is acting on, the slip ratios obtained by both methods show completely opposite tendency because the rotational deformation of the tire in transient state contributes significantly in the rotational behavior of the tire motion.