Synergetics Principles of the Regularity of the Development of Microcracks in Elementsof the Friction Units

In the study of tribological processes the highly nonequilibrium states of crystal lattice arise inside the frictional contact. It is no longer described by Hooke’s law, and undergoes a local structural transformation, besides its movement toward the equilibrium occurs as a synergetic process. However, the application of purely synergetics within the framework of continuum mechanics, by itself leads to the conflicting conclusions. The synergetic principles and the fractal approach of physical mesomechanics allow to describe kinetics of the plastic deformation and fatigue of various materials under different loading conditions from a single point of view, including the cyclic loading of tribocoupling, controlling of points of the bifurcation. In this paper, the stress-strain state of brake disks of transportation vehicles is analyzed to prevent the occurrence of microcracks on their working surfaces and the model is developed for studying nonstationary friction modes and fracture of contacting elements. The concept of metal fatigue is developed within the framework of physical mesomechanics. The proposed model explains the change in the mechanism of crack propagation under conditions of low-cycle fatigue of metal-polymer friction pairs when air enters the crack, and leads to the oxidation of fracture surfaces with the formation of a film. Perhaps, in this case, the formation of surfaces with a subgrain structure occurs.