Study on Deformation of Tires and its Similitude

Abstract

Similitude experiments were conducted on tire deflections and tread which gave an important effect upon the performances or behaviors of tractors or other vehicles.
Tire deflections and imprint were measured under various normal loads and inner pressures (Tab. 3) on both horizontal and inclined rigid planes (Fig. 1). The general tire deflection characteristics in relation to loads and inner pressures were obtained under all tire conditions. By comparing the test results with the theoretical values by a cylinder or a torus tire model, the torus model proved better to predict tire deformation (Fig. 9).
As shown in Fig. 11, similarity was obtained under the design conditions (Eq. 7) except an agricultural tire which seemed to have different construction and vertical rigidity from the three trailer tires S, M and L.
From the standpoint of tire performance, pressure scale should be 1 and then force scale becomes to n² (n; length scale) when the same supporting base is used for both prototype and model tractors. The design condition (Eq. 7e) satisfied the above restriction.