Journal of Machinery Manufacture and Reliability最新文献

The effect of aging on antiwear properties of lubricants based on solutions of zinc and molybdenum dithiophosphates in oils such as I-20A, PAO-6, and VHVI-6 (viscosity grade 32 by ISO) is studied. Zinc dithiophosphate is known as an antiwear and antioxidative agent, and molybdenum dithiophosphate is a high-temperature antifriction agent. Antiwear and antiscuffing properties have been estimated by GOST 9490-75 using a four-ball testing machine. During the first test, fresh lubricants are used; then they are aged by high-temperature catalytic oxidation using technique no. 42/607 dated May 10, 1983, by VNII NP, and the second test is carried out. According to comparison of the tribological test results for fresh and aged lubricants containing the DF-11 antioxidative agent, the acid number does not increase in some cases, which is caused by the introduction of antioxidation additives in such compositions.

An analysis of the influence of the direction of reinforcement in a composite material relative to the cyclic load on the heterogeneity of the distribution of local elastic strains measured by the thermal method of nondestructive testing is presented. In this study, the possibility of assessing the local distribution of stresses (strains) in the test object is demonstrated using the thermoelastic effect. The temperature field of the thermogram depends linearly on the stresses and strains at local points of the test object. Thermograms of laminates made of composite material with different arrangements of fibrous filler (fiberglass) with an epoxy matrix under cyclic loading were studied. To analyze the differences in the local distribution of strains, statistical data were used and variation coefficients were calculated. To visualize the strain levels, the clustering method and averaging of the temperature distribution values over the length of the laminates were used. The numerical characteristics of local temperature distributions were obtained, which showed a more uniform distribution when reinforcing the material in the direction of loading of the part.

The challenge of selecting sets of technological bases in the design of manufacturing processes for casing parts using multifunctional CNC machining centers is addressed. Through analysis, a graph representing the relationship of part surfaces was selected to depict the linear dimensions, orientation, and position tolerances, as well as runout. Furthermore, the selection criteria for the set of bases were established to include considerations of “impractical” bases, basing errors, the area and stability of the primary base, standardization of basing surfaces, alignment with typical basing schemes, and auxiliary time for mounting and dismounting the workpiece. Thus, considering these criteria, a methodology for selecting the optimal set of technological bases has been developed for the routing process of machining casing parts on CNC machining centers.

The bearing units of a high-speed ESP installation are considered. The choice of tribocoupling materials is presented based on the criterion of the conditional load-carrying capacity, which determines the comparative wear resistance of tribocoupling materials.

The application of a discrete wavelet transform, in particular Daubechies wavelets, to improve the accuracy and sensitivity of a leak detection system in main pipeline transport of oil and petroleum products is discussed. This study opens up prospects for further development and adaptation of the presented methods for transmitting technological information by communication channels.

Films of the CrMnFeCoNiCu high-temperature alloy have been deposited onto a steel substrate by vacuum sputtering in the magnetron evaporation mode. The local atomic structure and phase composition are studied. The structural state of the CrMnFeCoNiCu alloy is determined by the superposition of contributions of equiatomic simple cubic lattices with lattice parameters of the P1 space group. Reflexes from the S1 and S2 phases contribute to the integral intensity; the contribution is 65.7 and 28.9%, respectively. The spatial distribution of the atoms obtained by theoretical analysis for the S1 and S2 lattices confirms that the chosen composition is a solid solution and that secondary phases are absent.

The problems of ensuring high technical and economic performance of flexible automated lines of mechanical assembly production through the development of a methodology for determining the optimal parameters of the automated storage and retrieval system are considered. The functioning of a flexible automated line is simulated in order to verify the adequacy of the methodology developed. As a result of this research, an algorithm of the methodology for providing the optimal parameters of the automated storage and retrieval system is developed, the use of which makes it possible to increase the accuracy and reduce the labor intensity of the development of the design and technological solutions at the initial stage of design of automated lines of mechanical assembly productions.

A principal strategy for safeguarding oilfield equipment against corrosion involves the application of polymer coatings to their operational surfaces, thereby creating multilayer metal–polymer constructs. This paper presents findings from an examination of how the stress–strain profile of such multilayer structures alters under the influence of aggressive environmental conditions.

The problems of standardization of the shaft surface roughness for armored rubber cuffs are considered. It is revealed that a decrease in the shaft surface roughness leads to increased leakage, and with its increase, the wear of the cuff increases sharply. It is shown that the relative length of the profile bearing affects the cuff wear. In order to increase the durability of the sealing unit, it is recommended to standardize the surface roughness not only within a given range, but also to take into account the location of irregularities and the relative profile bearing length, which can be provided by surface-plastic deformation using rollers or balls.

The article systematizes the factors influencing reliability, identifies the failure rate at the operating stage for research, and proposes a fuzzy model for correcting the failure rate, taking into account the influence of real factors during operation. The results were tested on a Siemens-SGT-800 gas turbine.