Tire Force Generation on Ice
By theoretical arguments it is shown that the temperature in the contact patch of a tire sliding on ice can reach the melting point for normal operating conditions of ice temperature and sliding velocity. It is also shown that once the melting point has been reached a stable film of water can exist between the ice and the tire, thus making it possible to derive a mathematical model for estimating the traction forces generated in the contact patch. Traction forces are calculated from the model for a number of different braking and driving conditions and for different vehicle speeds. Comparison is made with available test results. Correlation with the test results is sufficiently good to verify the basic premises and predictions of the theoretical model.