The wear resistance of friction units with a polymer coating and a special groove in their supporting structure is increased by minimizing the heating of the contact zone of the rubbing surfaces through effective heat removal due to the presence of a transverse recess (groove). In addition, this design helps to minimize the dry friction process, since it directly affects the distribution of the lubricating fluid. Increased loads of friction units entail characteristic changes in the properties of lubricants. In our opinion, taking into account the viscosity indicators, depending on temperature and pressure, will allow us to more accurately characterize the operation of the structure in various friction modes. The effect of a modified friction unit design (with a polymer coating and a groove) on improving performance in general is described. In addition, comparing the standard and modified designs, it can be noted that the load capacity has significantly increased and the friction coefficient has decreased. At the same time, the service life and the overhaul period of the friction unit have increased, which is a significant effect for the mechanical engineering industry.

Keywords: friction unit, index, friction coefficient, polymer coating, load, tribocoupling

This article presents the results of theoretical research in the field of methods for determining the forces arising in the traction return ropes of the balloon system used in transport, cargo and construction works. The emphasis is placed on the accuracy of the swivel positioning when exposed to a wind flow on the balloon. Theoretical calculations of the main parameters are given, such as: high-speed head, resultant lifting force, rope span, rope force, rope deflection, swivel movement and others. A technique is proposed that allows for a relatively simple and rapid calculation of rope forces in the process of performing cargo operations by an aerostat crane on a construction and installation site.

Keywords: balloon system, balloon crane, traction and return ropes, rope forces, drag, aerial construction and installation work, swivel

This study is devoted to the development of a new mathematical model, a wedge-shaped sliding support with a non-standard elastically deformed support profile of the slider surface, taking into account nonlinear factors, under conditions of a two-layer lubricant flow, providing effective lubrication and reducing wear of the working surface. To develop this model, we will use mathematical modeling and data analysis methods to take into account all the necessary factors and parameters. To achieve this goal, well-known nonlinear equations are used: the motion of a viscous incompressible fluid for a "thin layer", the continuity equation and the Lame equation with appropriate boundary conditions, taking into account the elasticity and adaptability of the support surface of the slider, as well as equality of velocities at the interface of stratified layers, equality of pressure at the ends of the interval and equality of velocities on the surface of the guide. As a result, the main performance characteristics of the ras were identified

Keywords: nonlinear factors, elastically deformed, non-standard surface, flow of two-layer lubricant, dependence of viscosity characteristics of lubricating layers, ratio of density characteristics

The paper considers the problem of bringing vibrations of a flat membrane to rest, controlled by forces applied to the entire area of the membrane and limited in absolute value. Sufficient conditions are given for the initial data of the deviation and velocity of the membrane, under which a complete stop of motion in a finite time is possible. The resting time is also evaluated. The theorem on estimating the eigenfunctions of the Dirichlet problem for the Laplace equation used in the work makes it possible to refine the mentioned sufficient condition in comparison with the work of F.L. Chernousko. In this work, a similar problem is considered, and the method of expanding the unknown control and the corresponding solution in terms of eigenfunctions of the Dirichlet problem for the Laplace equation is also applied. In this paper, the problem of bringing various elastic oscillatory systems with distributed parameters (membrane, rod, plate, etc.) to a state of rest in a finite time is reduced by means of expansion into a Fourier series in the corresponding system of eigenfunctions to the study of the problem of stopping a counting system of pendulums, connected with each other only through the values of external control actions, the sum of the values of which should not exceed in absolute value some given constant. In order to fulfill this limitation, it is necessary to use estimates for the absolute values of the eigenfunctions, normalized in the mean square. In this paper, we use some estimates for the absolute values of eigenfunctions, previously obtained by Eidus D.M. This allows us to refine the results of F.L. Chernousko for sufficient conditions on the initial functions of the oscillatory system, under which we must dampen the oscillations. These conditions consist in the fact that the initial functions belong to Sobolev spaces with certain indices and in the fulfillment of some additional boundary conditions on the boundary of the domain in which the system is defined.

Keywords: control, wave equation, limited distributed force, Fourier method, counting system of harmonic oscillators