Periodic Intermittent Mode of Ice Surface Softening During Friction at Deformational Defect of Ice Shear Modulus

The mathematical model has been developed that describes the periodic mode of softening of the ice surface during friction on the case of deformational defect of ice shear modulus. This case corresponds to formation of premelted film with thickness about 10 nm by mechanism of first-order phase transition. Such film is very affected by noise due to small thickness. The second-order differential equations have been derived describing damped harmonic oscillations for limiting relations between the shear strain, stresses, and temperature relaxation times. In all cases, phase portraits and time series of friction force have been constructed. We show that white noise influence leads to an undamped oscillation mode corresponding to a periodic intermittent (stick-slip) regime of friction that is basically responsible for destruction of rubbing parts. The conditions in which the periodic intermittent regime is manifested most clearly have been determined, as well as parameters for which this mode is not observed for the all rubbing surface temperatures.