A hinge specifically designed for continuous friction measurements during ice skating was tested and used. The hinge can handle large vertical normal forces to simulate the weight of a real person...Show moreA hinge specifically designed for continuous friction measurements during ice skating was tested and used. The hinge can handle large vertical normal forces to simulate the weight of a real person on a skate, and is very flexible in the horizontal direction, so it deforms under a friction force. Two sensors on the hinge measure the deformation. Friction measurements were done with a part of a real skate, with varying temperatures, skating speeds and normal forces on the skate. A clear dependence of friction on temperature was found. Friction coefficients for an ice temperature of -20 C and air temperature of -10 C varied between 0.04 and 0.1, and coefficients for an ice temperature of -10 C and air temperature of -6 C varied from 0.006 to 0.016. The temperature of the skate was held at -10 C for both cases. The results also suggest friction dependence on skating speed and normal force, but this has to be verified. During the calibration of the setup it was found that the vertical force, controlled by air pressure, could be determined up to a factor of 2. Furthermore there was a large variation (up to a factor 2) in friction coefficients from measurements under the same circumstances, on the same ice layer. These could have been caused by changing humidity in the setup, as this was not monitored during the measurements. The setup works, but needs to be improved for more precise friction measurements. A humidity sensor in the setup is recommended.Show less
During this study, a device was developed which is capable of measuring the friction coefficient between two macroscopic solid samples for different rotation angles. It is based on an Anton Paar...Show moreDuring this study, a device was developed which is capable of measuring the friction coefficient between two macroscopic solid samples for different rotation angles. It is based on an Anton Paar rheometer. It can measure torques ranging from 10 nNm up to 200 mNm, while controlling the rotation angle with a minimum resolution of 10 nrad. The normal load exerted on the samples can be controlled with mN accuracy. Measurements on HOPG and silicon dioxide have verified that the instrument works and is capable of measuring very low friction coefficients as a function of the rotation angle between the two samples. The obtained friction coefficients are in agreement with values found in literature.Show less
