Stochastic Description of Dry Friction in Metal-to-Metal Contact Under Harmonic Excitation

Abstract

Experimental measurements of dry friction between sliding surfaces under harmonic excitation show that the friction force consists of periodic components with superimposed random fluctuations. The stochastic nature of the friction can be Gaussian or non-Gaussian, depending on the normal force and excitation amplitude levels. The normal force experiences random fluctuations due to ploughing and generation of surface asperities. The main influence of friction damping on the system response has been examined under different levels of normal loading. It is found that with increasing normal force the relative displacement deviates from the original sinusoidal nature and becomes essentially nonlinear with periodic motion. Regions of high displacement show this nonlinear behavior, which experiences extensively stick-slip with increasing normal force. Numerical simulation results are found to be in good agreement with experimental results.