Creation of the tribological model of contact wear of a rail depending on grinding process parameters

Abstract

Background. The current operating conditions of railway transport characterized by an increase in the power of locomotives, train speeds and carrying capacity, which leads to increased force influences on the railway track. Extreme operating conditions lead to increased wear and damage to rails on the reliability of which depends not only on traffic safety, but also the economic performance of the railway. Defective layers of the material removes from the surface of the rail by the rail grinding process. Thus, provides the required sizes and shape accuracy, as well as surface quality of rails during their operation. Objective. The aim of this work is to develop a tribological model of contact wear of rails during their operation depending on parameters of the grinding process (temperature t, grinding depth of cut ae, grinding wheel speed V). Methods. The research on wear and contact damage of samples of surfaces cut from grinding rails conducted on a friction machine M-22M. The studies were carried out by dry friction of a sample (cut from a rail) with a counter-sample from the material used in the manufacture of railway wheels, for 1 hour, the friction path was 3.60 km. Samples were weighed on a VLR-200 balance before and after the study was performed on the friction machine. As a result, the mass wear value was determined for each sample. A numerical model created in the Ansys program for numerical simulation by the finite element method of the rail-wheel contact to determine the contact pressure distribution and the wear intensity of the rail. Results. Based on the results of tribological studies in the paper established the empirical dependence of the wear intensity of the rail sample on the grinding process parameters. The contact conditions of the rail sample with the counter-sample during the tribological experiment and in real contact of the rail-wheel are different. Therefore, we performed the alignment of that empirical dependence to the actual conditions of contact of the wheel with the rail. The rail-wheel contact simulation performed in ANSYS Workbench. The dependence that given in the paper used in the program. It used to calculate the wear intensity of the rail according to the distribution of contact pressure in the contact zone of the wheel and rail. The results of the work can find practical application in railway transport to predict the effect of grinding proces parameters on the wear intensity of the rail. Conclusions. The dependence obtained for the approximate value of the rail wear intensity depending on the grinding process parameters (temperature t, machining allowance ae, linear speed of the grinding wheel V) based on the experimental data obtained from tribological experiments on the M-22M friction machine with grinded rail samples. The mathematical model has developed for calculating the contact pressure and the value of the rail wear intensity depending on the number of load cycles in the ANSYS program.