Journal of Machinery Manufacture and Reliability最新文献

The dependence of the reaction rate on temperature and pressure is considered from the standpoint of chemical kinetics, and an attempt is made to explain the increase in friction force after a decreasing load on the contacting surfaces and attaining the minimum with an increase in the sliding velocity. Thermodynamic aspects of the transition state theory and the cases wherein the reaction itself causes resulting deviations from equilibrium are considered.

The results of this study are presented, aimed at justifying, including through experimental methods, the feasibility and prospects of using a high-concentration energy flow (ultrashort pulse laser) for the preparation of surfaces of worn parts for subsequent application of protective coatings by plasma methods. The relevance of solving the tasks related to improving the quality of surfaces processed with high-concentration energy flow has been demonstrated. The results of tests on samples made from traditional materials used in the manufacturing of technological equipment are provided. The influence of the angle of inclination and the power of the ultrashort pulse laser on the roughness of the processed surface is shown. The main research directions, supported by positive results from preliminary experimental data, are formulated. Practical recommendations for using the ultrashort pulse laser for the preparation of surfaces of worn parts are given.

Experimental studies of the temperature and pressure of the lubricant layer between friction surfaces are discussed. A description of the experimental setup is provided, which allows measuring the oil temperature, friction surface temperatures, and lubricant layer pressure.

The magnesium alloy ZK60, which is processed using laser shock processing technology at different laser energies, is examined. Finite element modeling of the laser shock processing technology was carried out to study fretting–corrosion wear of the magnesium alloy ZK60 in an environment simulating body fluids (Hank’s balanced salt solution, HBSS). The mechanical characteristics and fretting–corrosion wear of the magnesium alloy before and after processing using the laser impact hardening technology were investigated. The results showed that the maximum reduction in fretting corrosion wear using the laser impact hardening technology was approximately 73.4%. It is shown that this technology can be applied successfully to reduce the rate of corrosion and fretting–corrosion wear of ZK60 magnesium alloys operating in the HBSS environment.

A project for the development of oil and gas fields, which provides for several systems, including a system for collecting, preparing, and transporting natural and associated petroleum gas through field gas pipelines, is discussed. The main results of the scientific approach to the influence of gas-dynamic forces on the characteristics of a field gas pipeline are presented. The influence of the physical, chemical, thermodynamic, and technological parameters of natural or associated petroleum gas during its movement on the properties of the gas and the characteristics of the field gas pipeline is also considered.

This article discusses the development of a mathematical model and experimental study of a modified design of a radial sliding bearing. The peculiarity of the bearing design is the nonstandard support profile, on the surface of which a polymer coating with a groove is applied. Special attention is paid to accounting for the compressibility of the lubricant material in a turbulent flow regime. The results can be used for further improvement of bearing designs, which will increase their reliability and durability in various industries.

A technology for repairing hydrotreating reactors at an oil refinery using a robotic automated welding/cladding complex is proposed. The technological process of surfacing by means of a robotic welding complex is described for the example of repair of a hydrotreating reactor operated at oil refineries. One of the features of the proposed technology is the use of modern video cameras with laser illumination and liquid cooling. An algorithm for controlling a welding robot based on machine learning methods and fuzzy logic is presented. The technology described contributes to a significant increase in the service life of hydrotreating reactors due to timely repair in the shortest possible time, as well as to an increase in the efficiency of the repair operator’s work by limiting the influence of the human factor.

It is proposed to use the language of mathematical logic (predicate logic) to construct models. Examples of the verbal descriptions of the proposed models for diagnostic processes are presented. In this paper the role played by logical simulation in the analysis of technological systems is considered. In addition to the practical application of this method for an automated technological system of operations (ATSO), the interactions between the components of this system are considered.

In this article, the use of seismic monitoring methods is proposed to solve the problems of automated detection and evaluation of the characteristics of moving railway trains, as well as real-time analysis of the condition of tracks and roadbeds. A mathematical model of the seismic signal from moving railway transport has been developed, with the help of which the modeling of the characteristic impulse arising during the passage of a two-axle wheeled railway bogie was carried out. It was tested using the developed model of the railway transport monitoring system.

Random loading processes in parts of transport and technological machines in operation have a wide range of properties and can also be classified and processed in different ways. Useful tools for analysis, generalized in this article and developed for the first time, were applied to processes of different types. It is shown that transforming a non-Gaussian process to a Gaussian one gives comparable results.