Browsing by Author "Monia, Andrii H."

Now showing 1 - 3 of 3

Mathematical Model of Mine Locomotive Pulsating Braking by a Disc Brake
(Dnipro University of Technology, Dnipro, 2025) Monia, Andrii H.
ENG: Development, solution and analysis of a mathematical model to determine the dynamic and kinematic characteristics of a mine locomotive drive during braking with a pulsating braking torque. The methods. Forced oscillations of the elements of the wheel-motor unit (WMU) of a mine locomotive during braking with a disc brake were investigated using the methods of differential calculus and mathematical modeling. The integration of the system of differential equations was performed using the Runge-Kutta method. Findings. A mathematical model has been developed for braking a mine locomotive using a disc brake, which creates a pulsating braking torque on the axle of the wheelset, depending on its angular coordinate, taking into account the nonlinear dependencies of the adhesion coefficient on the relative slip in the braking mode of the mine locomotive for various track conditions, on the basis of which the braking torque parameters are established, allowing for improvement of braking characteristics. The friction characteristics of the interaction between the wheel and the rail during braking with a pulsating braking torque in mine conditions are theoretically substantiated. By means of mathematical modeling of the process of braking a mine locomotive with a disc brake, which creates a pulsating braking torque on the axle of the wheel pair, the parameters of the braking torque were established, ensuring high braking characteristics. The originality. The dependences of the path and speed of the locomotive, the angular velocity and relative slip of one of its wheels, the coefficient of adhesion and the adhesion force of one of the locomotive wheels to the rail, the difference in the linear speeds of the locomotive and one of its wheels, the longitudinal force in one of the rubber-metal hinges of the wheel pair suspension on time during braking with a pulsating braking torque were obtained. Practical implementation. A scientifically based engineering technique has been developed that allows, at the design stage, to select rational parameters of the disc brake of a mine locomotive, which creates a pulsating braking torque that ensures the implementation of the maximum braking force on the wheel-rail coupling during braking and determine the dynamic and kinematic characteristics of the mine locomotive drive during braking with a disc brake with a multi-sector disc under different initial data (rail track condition, train weight, initial locomotive speed).
Mathematical Model of Viscous Incompressible Fluid Motion between Wheel and Rail during Braking and Acceleration
(Dnipro University of Technology, Dnipro, 2024) Monia, Andrii H.
ENG: Purpose. Development, solution and analysis of a mathematical model of the motion of a viscous incompressible fluid in the contact zone of a wheel and a rail to establish the characteristics of rolling a wheel on a rail in the presence of an intermediate medium during braking and acceleration. The methods. To describe the motion of a viscous incompressible fluid, the Navier-Stokes equations in the polar coordinate system are used. The solution of the system of linear algebraic equations was performed using the Gauss method. To satisfy the velocity and pressure vector projection functions to the boundary conditions, the method of weighted residuals in the form of point-wise collocation was used. Numerical integration was used to determine the lifting force of the intermediate medium and the viscous drag force due to the presence of the intermediate medium as functions of relative sliding. Findings. The influence of the intermediate medium on the characteristics of wheel-rail adhesion under negative and positive relative slips is substantiated by mathematical modeling of the process of rolling a steel wheel on a rail. It is shown that in order for the ratio of the increase in the relative lifting force of the intermediate medium to the increase in the relative force of viscous resistance compared to the values of these quantities during free rolling to not exceed unity, it is necessary to limit the absolute value of the relative slip to 8.5%. The originality. For the first time, the influence of an intermediate medium with the properties of a viscous non-compressible fluid on the characteristics of the wheel-rail friction contact under negative and positive relative slips has been substantiated. The relationship between the increase in the relative lift force and the increase in the relative force of viscous resistance on the relative slip was found in comparison with the values of these quantities during free rolling. Practical implementation. A scientifically based engineering method has been developed for determining the relative lifting force of the intermediate medium, the relative force of viscous resistance caused by the presence of the intermediate medium, and the ratio of the increase in the relative lifting force to the increase in the relative force of viscous resistance compared with the values of these quantities during free rolling as functions of relative slip for given initial data.
Mathematical Modeling of Pulsating Braking of a Mine Locomotive during a Long Descent
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Monia, Andrii H.; Matsko, V. Y.
ENG: Mathematical modeling of the process of braking a mine locomotive with a disc brake on a long slope with a non-linear braking moment was carried out.