Dry friction experiments: Slider in a turntable

Abstract

Friction theories have been developed for centuries. Even so, most of them are empirical and there are many cases where the experimental results cannot be explained with the models. The principal cause of this fact is the nonlinearity of friction problems. The aim of this work is to study dry friction with the design of an experimental setup based in a slider on a turntable attached into an external fixed point. The implementation of a tracking program is needed to follow the slider trajectory. In particular, stick-slip phenomena has been produced with mass-spring system with two degrees of freedom. We have done a qualititative analysis of the results comparing them with the steady sliding case, in order to understand better the nonlinearity of friction. In addition, we have solved numerically the equations of motion of the slider in the framework of Coulomb model of friction to compare the solution with the experimental results. Our study shows that friction is a non-linear problem and that Coulomb model is not valid to explain our experiment but can predict the period of stick-slip oscillations.