INDAGINE SPERIMENTALE DELLE CARATTERISTICHE DI ATTRITO PNEUMATICO-STRADA

The main objective of this work is to investigate whether it is possible to determine a relationship between the visco-elastic properties of rubber and friction by emphasising the importance of tyre surface temperature in contact with road during a braking manoeuvre. After an overview of rubber friction mechanisms and material properties, the study provides a detailed description of a typical indoor flat-track test rig used to obtain a set of data that are usually parameterised to obtain a simulative tyre model. The results obtained from the tests will be related to the material properties, obtained through dynamic mechanical analysis, to try to derive a relationship between the friction and the rubber properties, as in the work carried out by Grosch. In addition, a braking manoeuvre will be analysed using a simple brush model to highlight how tyre temperature and surface characteristics can influence the maximum friction value achievable under sliding conditions. Finally, it will be discussed how the maximum friction value influences the maximum deceleration applicable during braking and therefore the stopping distance of the vehicle, pointing out that a good tyre simulation model cannot neglect the influence of temperature.