Purpose. Determination of the regularities in the variation of the coupling parameters of the wheel-rail pair and the energy consumption accompanying them, taking into account the thermophysical processes in the contact zone in the transmission of friction motion for various interaction conditions. methodology. An analytical model for the interaction of a wheel and a rail on an elementary contact spot is developed in the presence of normal and tractive effort. A dependence that describes the change in the average temperature at the contact spot of the wheel-rail pair on the locomotive speed is obtained. The current value of the elasticity modulus of the contacting pair material is determined as a contact time function. findings. Based on theoretical studies of the parameters of vehicle motion along the railroad track, a mathematical model of the tractive force realization for nonstationary rectilinear motion is formulated. To determine the influence degree of the temperature change on the contact spot of the wheel-rail pair associated with the speed of the locomotive motion and the relative speed of the output links, the dependences for the coefficient characterizing the tractive power of the vehicle are obtained. originality. Taking into account the thermophysical processes that occur during the interaction of contacting bodies, analytical dependencies have been obtained to determine the traction capacity for different movement speeds and the relative speed of the wheel and rail movement for main and mine locomotives. The dependencies suggested take into account the change in the properties of the surface layers of the contacting pair. Practical value. Knowledge of physics of the processes occurring in the contact zone of the wheel-rail pair will allow more accurately predicting the vehicles tractive properties, comparing possible options at the design stage and greatly accelerating the process of selecting the structural scheme. This will allow developing recommendations and proposals on modernization and improvement of existing vehicles.

No abstract

The increase in the share of electric transport in mining and municipal enterprises in the short term may lead to changes in the structure of the transport fleet of enterprises and can affect the technology of work, in particular, surface mining operations. Changes in technology relate to the need for charging batteries, as well as the appropriate economic and technological planning. Having implemented the combinatorial representation and using the chain diagrams, a new method has been developed for determining the optimal plan of the vehicles flow distribution at the charging station of industrial enterprises, which provides the greatest enterprise profit. The developed mathematical model of vehicle flow at the charging station is compiled taking into account the objective constraints related to the cyclicality of the station loading capacity. The optimal plan for the vehicles flow distribution at the charging station is, based on geometric representations, as the greatest distance from the beginning of the reference to the plane (hyperplane), which passes through the vertex of the polyhedron of the area of admissible solutions and is oriented by the gradient of the target function (enterprise profit). The task becomes urgent in the light of the electrification of industrial transport and the improvement of batteries for them.

Purpose. To ensure the effective functioning of the area for diagnosis and repair of tractive electric vehicle (EV) battery by determining the technical and economic indicators of the production capacity of the enterprise. Methodology. Modelling the process of repairing section of the EV traction battery is performed using the main principles of the queuing system, the graph theory. While calculating the probabilitytime characteristics and determining the production ca pacity of the site, the methods of mathematical statistics and probability theory were involved. findings. With the use of systematic approach, the EV market in Ukraine and the dynamics of the demand over the past three years have been studied. There was collected and analyzed information about issues related to the EV operation, and the most common ones were identified. Empirically, there was obtained an estimate for the duration of the process of repairing and replac ing the EV traction battery, as well as the cost of basic operations. The battery repair section of the traction battery is represented as a multichannel queuing system, assuming that the flow of applications for diagnosing and repair is Poisson's flow, and the ran dom process is Markovian. The problem of rational organization of the EV traction battery repair site has been solved by determin ing the minimum number of repair posts, at which the queue will not grow indefinitely (if customers can wait for their service for a long time and do not leave the queue). The number of repair posts was estimated for the traction battery, which in the existing conditions will allow organizing technical customer service effectively, minimizing the total economic losses from downtime of process equipment and refusals of applications for repairs. originality. The use of models and methods of the queuing system for the calculation of technical and economic indicators of the production capacity of the traction battery repair section allowed taking into account the stochastic nature of the needs for repaire, and determining the optimal values of those characteristics that ensure the efficient performance of the EV repair section. Practical value. The proposed method for determining the production capacity of the repair section of traction battery is used in solving problems related to the selection and rational placement of technological equipment when designing or upgrading a workshop.