Characterization of Static Friction and its Dependence on the Contact Time

Several studies on acoustics and vibration have been encouraged due to the automotive industry's interest in projecting less noisy braking systems. In the interest of furthering these kinds of studies, understanding one of the main vibration excitation phenomena in friction systems, the stick-slip, is very important. Stick-slip is an auto-excited vibration that might occur in a fixed body that frictions with another moving body, based on the difference between the static and kinetic friction force. For this reason, characterizing the friction material regarding the static and kinetic coefficients seems to be essential for developing simulations and experiments. On the other hand, the characterization of the static coefficient is very complex due to its dependence on time while the surfaces were in stationary contact. Therefore, this study has the objective of making an experiment able to obtain equations that characterize the friction material regarding the time while the surfaces were in stationary contact.