Relation between Kinetic Friction Coefficient and Angular Acceleration during Motion Initiated by Dynamic Impact Force

Abstract

The paper presents theoretical and experimental analyses of the kinetic friction coefficient of a ball bearing in conditions of rotational motion initiated by dynamic impact force. A method has been developed and a measurement system allows the measurement of a kinetic coefficient of friction through the measurement of the angular acceleration. This paper considers the friction caused by rotational motion initiated by the force impact impulse. After the external force (impact impulse) stops acting, the motion continues, and the loaded bearing (i.e. the zone of the bearing in which the frictional resistance forces act) exhibits a broad spectrum of velocities, from the maximum value at the moment of motion initiation to the zero value when motion stops, where the whole measuring system acts as a rotary encoder. Experimental results indicate a high dependency between angular velocity and friction coefficient, similar to functional dependency. This paper proves that kinetic friction coefficient can be reliably measured using the measurements of angle change and angular velocity. Analysed method has high potential in the diagnostics of energy loss in the tribo-mechanical systems.