Journal of Machinery Manufacture and Reliability最新文献

The results of the study and implementation of a unique wave technology for processing cement slurry with increased performance characteristics in the construction of oil and gas wells are presented. Based on a theoretical justification of the effect of waves with a certain spectral characteristic on cement slurries, a methodology was developed and experiments were carried out in laboratory and field conditions, which made it possible for the first time in the world to create a wave technology for processing cement slurry. The wave technology for preparing cement slurries has been tested in field conditions at oil industry facilities and has proven to be highly effective. Wave technology for processing the cement suspension also has broad prospects for use in construction, especially in the construction of facilities with increased requirements for the strength of concrete structures.

The low durability of chemical pumps when operating in a kimberlite mine is stipulated by frequent failures of their bearings. Based on the results of this study, the main cause of premature bearing failure was identified and recommendations to eliminate it were proposed.

This article presents the results of the ball-on-disk wear test (ASTM G99) and linearly reciprocating ball-on-flat sliding wear test (ASTM G133) for molybdenum disulfide–based coatings in a wide range of operating conditions. Monocomponent suspension coatings based on molybdenum disulfide and doped with graphite, ceramics, and polytetrafluoroethylene are studied in a vacuum, at elevated temperatures, and under normal atmospheric conditions. The friction coefficient and service life of the coatings are determined depending on the application technology and operating conditions. The structure and chemical composition of the coatings and the mechanisms of coating wear and destruction are studied.

The impact of the orientation angle and stacking order of the composite material on the torsional strength, buckling, and natural frequency of the drive shaft was demonstrated in a number of investigations. When designing and analyzing various composite materials, carbon/epoxy and Kevlar/epoxy were further looked at for their suitability in terms of torsional strength, torsional buckling, and bending natural frequency of the drive shaft. However, the fatigue life of these materials is not student very well. This, study will analysis the property of carbon/epoxy and Kevlar/epoxy composites automobile drive shaft fatigue life in addition to weight, bending natural frequency and equivalent stresses analysis. Before designing composite materials, the steel drive shaft will be designed and analysis based on weight, torsional strength, torsional buckling, bending natural frequency and fatigue life as a reference for comparison. Then, utilizing a modeling equation, ANSYS 18 and Solid work 16 as a tool, numerical and analytical analysis is carried out. Analytical and numerical results are contrasted as part of the validation process. The driveshaft made of carbon/epoxy composite material greatly reduces the weight of the driveshaft when compared to steel and Kevlar/epoxy drive shafts by comparing both analytical and numerical data. In contrast, the increased number of plies in the Kevlar/epoxy drive shaft gives it a longer fatigue life than the steel, carbon, and epoxy drive shafts. As a result, it is stronger against shearing and buckling loads.

The influence of the curvature of cylindrical bodies on their elastic approach upon initial linear contact has been studied. It is shown that the approach of two circular cylinders depends on the sum of their radii of curvature, and does not depend on the radius of curvature of an individual cylinder. It is shown that despite the fact that the reduced radius of curvature at the meshing pole of the gears is greater than at the point of their engagement, the contact stiffness does not change, because the sum of the radii of curvature at these points is constant. Analytical equations in general form are obtained to determine the influence of curvature on the approach of elastic bodies upon initial contact along a line.

A method of synthesis of an internal bevel gear by coefficients of profile shift and shaft angle is presented. Formulas for calculating qualitative rates are derived: slip ratio, specific pressure ratio and overlap ratio. It is noted that such gear in comparison with the external bevel gear is characterized by better qualitative rates. These calculated dependencies are the basis for the work of the Internal bevel gears x64 program to generate macros for modeling such gear. The internal toothed wheel can be manufactured on a three-, four-, or five-axis CNC milling machines, as well as on a 3D printer.

In this article, a comprehensive methodology has been developed to study the lubricity of oils with solid micro/nanoadditives, including mathematical models that allow estimating the temperature during shear and variable speed in the layer. The dynamic temperature gradient across the thickness, the variable thickness, the friction moment, and the temperature are calculated.

In screw volumetric machines, cycloidal screw surfaces of complex profile are used as working bodies. This paper is devoted to study of the technological possibilities of preparing the production of such screw surfaces using a special processing strategy with a nonprofiled tool on a 4-axis CNC machine. During this study, a special analytical criterion was proposed to evaluate the possibility of processing screw surfaces with various parameters. A computer experiment was performed to confirm the performance of the proposed criterion, as well as a series of full-scale experiments.

A finite element algorithm in a mixed formulation has been developed to find stresses and displacements occurring in a shell of revolution. The finite discretization element has been taken in the form of a curvilinear quadrangle of the middle shell surface. As the nodal unknowns in the mixed formulation, forces and moments inherent in the middle surface with a bilinear approximation have been used, as have the displacements and their first derivatives in two approximation variants of the sought kinematic quantities in scalar and vector form. By the example of calculations, the efficiency has been shown for the approximation of the sought kinematic quantities as vector fields, and it has been noted that the determination of stresses occurring in shells of revolution made of incompressible materials is quite possible.