Mathematical model of running-in of tribosystems under conditions of boundary lubrication. Part 2. Simulation results

Abstract

The paper presents the results of mathematical modeling of tribosystems running-in processes when various factors are changed: design parameters of tribosystems, which are taken into account by the form factor; tribological properties of the lubricating medium; rheological properties of composite materials in the tribosystem; roughness of friction surfaces; load and sliding speed. By comparing the theoretically obtained results, by modeling according to the developed models, with experimental data, it was established that the mathematical model adequately reflects the running-in processes taking into account the changes in constructive, technological and operational factors. Applying the Cochrane criterion, it was established that the obtained experimental results are homogeneous and reproducible. The maximum value of the coefficient of variation of the values of the volumetric wear rate and the coefficient of friction is within the limits v = 12,3 - 26,5%. The value of the simulation error is within the limits v = 7,7 - 12,9%. A rating of factors that maximally affect the processes of running-in of tribosystems in the conditions of extreme lubrication has been obtained. In the first place is the roughness of the friction surfaces, the coefficient of variation v = 26,5%. In the second place – the load on the tribosystem during running-in, the coefficient of variation v = 20,8%. In third place is the value of sliding speed during running-in, the coefficient of variation v = 18,6%. The conclusion made must be taken into account when developing a rational program for running-in tribosystems in conditions of extreme lubrication. The methodical approach of applying the acoustic emission method in the study of tribosystem running-in processes is presented. It is proved in the work that in order to determine the volume rate of wear during tribosystem running-in, it is necessary to register and analyze the fourth cluster from the general acoustic emission signal. The sources of signal generation of the fourth cluster are microcutting and plastic deformation of protrusions of the roughness of the friction surface, which is characteristic of the first stages of running-in.