Geometry and kinematics of the plate on disk contact type influencing friction measurements on UMT tribometer

Abstract

The paper presents theoretical bases and experimental test on the pin on disk module of the UMT tribometer. In order to determine the friction coefficient between a chain and a guide, the rotational pin on disk module of the UMT tribometer has been adapted using a plate of the chain (instead of the pin) pushed against a rotating disk made from the guide material. In this case the contact surface between plate and disk is a rectangle. In comparison with the pin on disk case, the differences between sliding velocities on the rectangular contact surface of the plate on disk case may be considerable bigger. Study of kinematics shows the maximum and minimum sliding velocities and friction forces. The relative extreme sliding velocities and friction forces are expressed depending on geometrical inputs. The study continues with the measurements of friction coefficients maintaining the same couple of materials, surface dimension, normal force and sliding velocity at the centre of the rectangle with variation of the radius. Conclusion is drawn on the influence of the geometry and kinematics of the plate on disk measured friction.