Experimental studies of translation-rotational motions of rolling bodies under elastic-frictional interaction with the bases

Abstract

Experimental studies and their results are described for the translation-rotational motion of rolling bodies subjected to forces and elastic deformations of the contact tribological conjunction regions between such bodies and the bases. Most attention is paid to the motion of such bodies outside the contact surfaces in the regions of preliminary displacements and behind these regions. In several experiments, the processes are recorded and analyzed from the very beginning to the termination of the rolling body finite displacements. All displacement stages exhibit oscillations due to variations in the character of motions of the rolling bodies. In the case where the body is only under the action of its weight, the regions of normal strains symmetric with respect to the axis of the weight action are shown as surface indentations outside the region of direct contact between the base and the rolling body. The photographs of the base nonsymmetric deformations due to the additional action of the tangential force on the rolling body are presented. One can see that the indentation slope in the motion or the force action direction is steeper and the indentation depth and length are smaller than those on the opposite side. This suggests that, on the side where the rolling body surface enters the base, the volumes of their deformations and hence the elastic force are greater than on the opposite side. The graphs are constructed for the variation in the values of preliminary and kinematic (in motion) displacements and the arm of rolling friction force for two motor cars, for a solid steel roller, and for a steel roller with two foam rubber wheels. The graphs show that, quantitatively, the displacement values are by one and more orders of magnitude greater than the values of these arms of force. Qualitatively, the arms of rolling friction force, just as the displacements, are characterized by the presence of proportionality and saturation segments of their characteristics. The motion processes of the considered rolling bodies in the directions opposite to those in which each of the bodies moved under the action of the tangential external force are also shown.