No 5 (2023)

The results of comparison of the methods of studying the parameters of embedding reliability for the side rack unit, which is one of the most critical units of the pipe transportation train car platform, are presented. We show the inaccuracy of the existing methodology for calculating the train car platform side rack loading parameters affecting the reliability and safety of freight transportation; we also propose a new calculation method applying nonlinear static analysis with account for the pipe rolling force.

This paper is devoted to study of increasing the wear resistance of a radial plain bearing. The operation of a bearing is considered in the hydrodynamic mode by means of application of an antifriction polymer composite coating with an axial groove and the micropolar properties on a nonstandard bearing surface adapted to the friction conditions of a bearing bush. The effect of pressure and temperature in the turbulent friction mode on the rheological properties of the lubricant is taken into account. Based on the equation for the micropolar fluid flow in a “thin layer” as well as on the dependence of the micropolar lubricant on the pressure and temperature and on the continuity equation, a self-similar solution has been found taking into account the axial groove on the surface of a bearing bush and without taking into account the axial groove. As a result, the velocity and pressure fields in the axial groove and on the surface of a polymer antifriction composite coating have been determined as has the load capacity and friction force, which make it possible to increase the load capacity, reduce the friction coefficient (increase wear resistance), and also increase the duration of the hydrodynamic mode. The results of numerical analysis of theoretical models and experimental evaluation of the suggested design are presented to verify and confirm the efficiency of the models obtained.

Our country has been undergoing processes related to the reorganization and improvement of agricultural production services. The Soyuzselkhotechnika system was organized to replace the machine-technological stations. The development dynamics of Soyuzselkhotekhnika shows the volumes of marketable products, and it is particularly noted that the markup on all services used to be only 12.6%, and now it has risen to 45%. The volumes of reconditioning of parts at the enterprises of Soyuzselkhotekhnika are given; more than 60% of the names of parts were restored. Achievements of individual enterprises in the implementation of efficient technologies are shown. It is confirmed that the reconditioning of worn parts at the enterprises of Soyuzselkhotekhnika annually saved for the country up to 12% of new spare parts, over 500 000 tons of casting, and 150 000 tons of rolled products. The role of sectoral science and academic science is shown. The created system of Soyuzselkhotekhnika enterprises was an effective assistant for commodity producers not only in providing new machines and assemblies, but also for remanufactured parts with high quality, low price, and guaranteed performance.

Methods that make it possible to evaluate the heterogeneity of the distribution of local strains and stresses indirectly through the values of the temperature distribution in thermograms are presented. In this case, methods of fractal analysis in the form of multifractal spectra, image clustering, and multiscale analysis of discrete wavelet images decomposition are used. It is shown that, with increasing damage to the material, the width of the multifractal spectrum increases and local strains are redistributed along the plate length during loading. The use of the multiple-scale wavelet decomposition makes it possible to establish scale elements that have the greatest strain changes.

Laser shock forming is an innovative technology in which a laser shock wave induces a flexural deformation of a thin plate. Naturally, the technology of laser shock forming cannot increase the curvature of the plates indefinitely and its possibilities have limits, especially for thick plates. This article investigates the maximum convex flexural curvature of a plate that can be achieved using the technology of laser shock forming by successively increasing its main characteristics: the laser spot overlap factor, the number of repetitive laser pulses, and the intensity of laser power density. The resulting flexural torque and bending curvature are calculated from the average residual stresses obtained by the finite element method. The proposed method for predicting the plate curvature can effectively predict the flexural behavior of the plate. This allows one to plan the process of laser shock forming properly.

В статье рассматривается способ воздействия на объект теплового сигнала, являющегося широкополосным сигналом ТГц-диапазона. Генерация сигнала осуществлялась тепловыделяющими элементами тканых электронагревателей на основе углеродных нитей. Воздействие тканых электронагревателей производилось контактным способом на отдельные участки объекта. Также с помощью сигнала ТГц-диапазона была получена неинвазивным путем количественная информация во времени о кожно-гальванических реакциях и др. Настоящая статья представляет интерес для специалистов, занимающихся в области теплофизики, материаловедения, физиологии, медицины и т.д.