Tri-axial Contact Reaction at the Tire-Soil Interface

The contact stresses between a tire and sand were measured with a tri-axial force sensor embedded on the tread surface of the tire. The results showed that the sensor could detect normal and tangential contact reactions with sufficient accuracy. Moreover, we observed a forward shift of the rotational angle for which both normal and longitudinal tangential stresses are maximum. There were three points of measurement on the lateral direction of tire tread, and the tractive performance of a tire in terms of gross tractive effort, drawbar pull, and running resistance could be obtained through integration using the detected contact forces.