Friction Force Reduction Efficiency in Sliding Motion Under Tangential Vibrations of Elastic Support

The efficiency of reducing the friction force in sliding motion under the influence of forced vibrations of an elastic substrate significantly depends on the direction of these vibrations in relation to the sliding direction. This article presents a comparison of computational models developed by the authors to estimate the friction force in sliding motion under longitudinal and transverse tangential vibrations of the substrate. Fundamental differences between these models are discussed, and the results of comparative analyses of the impact of tangential vibrations on the friction force depending on their direction are presented. In the developed models describing the friction force, dynamic friction models of Dahl and Dupont and the so-called LuGre model were utilised. The analyses were performed as a function of the sliding velocity and two basic parameters of vibration, which are frequency f and amplitude u0. It has been shown that under longitudinal vibrations, the key parameter, which determines the occurrence of friction force reduction at a given driving velocity vd, is the amplitude va of vibration velocity. However, the level of this reduction cannot be determined unequivocally based on the value of this parameter alone since the identical value va can be obtained at different magnitudes of the frequency and amplitude of vibrations, and the reduction level is a nonlinear function of these parameters. The results of simulation analyses were verified experimentally.