The objective of this work is to identify and understand the importance of the various physical phenomena involved in the interaction between tyre and ice. On one hand, many legislations tend to prohibit the use of studded tires and the actual aim is to obtain high friction on ice by other means. In order to understand the physical mechanisms which act during the scraping of ice, an experimental device was designed. It allows to measure three types of friction coefficients between various indenteurs and ice. A sledge supported by four friction blacks is launched by a pendulum on a 2m30 long horizontal ice track. Coefficients of friction are evaluated by means of digital image analysis or embarked accelerometer. On the other hand, an experimental prototype for measurement of friction between rubber and ice was developed to simulate the behavior during braking with locked wheel. An elastomer specimen of area lower than 20 cm2 is applied on a rotating dise of ice. Normal and tangential forces are measured by a sensor directly fixed on the sample. Observations of the facies of ice surface with a binocular provide qualitative characterization of friction . Experimental conditions are: nominal normal stress from 1 to 4 bars, sliding speed from 2 to 11 m/ s, ambient temperature between -20 and -5C. A decrease of one of these three parameters increases measured friction coefficient. Exposed results show also the effect of track wear, sample heating, contact area and distribution of normal stress.
