Journal of Machinery Manufacture and Reliability最新文献

Combined screw joints used in mechanical engineering and oilfield volumetric hydraulic drive devices and other areas are discussed. The possibility of creating combined valves by pressing and casting a part from plastic onto metal reinforcement has been considered. It has been established that the profile and screw pitch should be selected from the same calculation of the strength of the screw from metal and thermoplastic. It has been established that the determining role in the calculation is played by the length of the screw, and the minimum wall thickness is selected using screw profiles. It has been established that the shear strength of thermoplastic materials differs significantly from the shear strength of metallic materials.

Surface texturing is a promising sustainable technique to get better the machining performance of cutting tools. Laser surface texturing and micro-EDM are the most commonly used fabrication techniques and the textured tools exhibit better tool performance as compared to conventional tool. However, these processes involve resolidification of material surface which makes the surface softening and reduction in the surface hardness. In the present work, cutting performance of the high-speed steel (HSS) tool is studied by fabricating hybrid (microgrooves with dimples) textures on its rake face using both laser ablation and micro-EDM methods followed by laser shock peening without ablative coating (LSPWAC) process. Hybrid textured with shock peened HSS tools are used in orthogonal dry turning of 316 L stainless steel. It has been observed that hybrid textures with shock peened HSS tool exhibits higher tool life of up to 255 and 85% than the conventional and the hybrid textured (HT) tools respectively. The results shown that surface texturing followed by shock peening is an innovative method to improve the sustainability in machining process than only surface texturing method. Moreover, analysis of chip is studied by finite element analysis.

Based on literary and experimental data, the effects accompanying the passage of pulsed current and associated structural changes in metals and alloys have been considered briefly. The special role of the type and modes of current, as well as the nature of the material, has been shown. The results of studies of the interaction of electric current and plastic deformation by quasi-static tension in pure metals, titanium alloys with martensitic transformation, and steels have been presented. It is assumed that the causes of the detected deformation effects are the ratio of the period and duration of the pulse, cycling of stress and temperature, changes in the deformation mechanism, reversible transformations, changes in grain size, and the appearance of particles of second phases. Variation of the duty cycle makes it possible to regulate the ratio of thermal and electroplastic effects and thereby influence the mechanisms of hardening/softening.

As a result of theoretical studies, it was established that the coefficient of friction of the interacting surfaces of rail vehicles is significantly influenced by the roughness of the contacting surfaces, the actual contact area, the temperature in the contact zone of the wheel-rail system, and the speed of mutual sliding (slip) of the contacting surfaces. It has been established that, in order to ensure the strength criterion and reduce wear, it is necessary to limit the temperature in the contact zone of the wheel–rail system within 300°С by controlling the sliding speed of the wheel relative to the rail. It has been revealed that the effective functioning of the wheel–rail system can be realized through the interaction of the machined working surfaces of the wheel and rail with roughness Rz 20–40 µm. Implementation of the proposed technical solutions using tribological research methods will allow for the possibility of increasing the friction coefficient of wheel–rail systems by up to 27%.

A reduction in the James–Stein shrinkage estimator might significantly increase the accuracy of cluster analysis of k-means for a relatively broad range of data. The efficiency of using the James–Stein shrinkage estimator for automatically grouping industrial products in homogeneous production batches is considered. Tests are conducted for batches of integrated circuits by comparing the shrinkage results with those obtained using the traditional k-means algorithm. The dataset is normalized according to the values of the acceptable drift, acceptable parameters, and standard deviation. As established using the Rand index, clustering is far more accurate in the automatic grouping of industrial products in homogeneous production batches, when average values of inconclusive parameters drop to zero. It is established that the reduction of the James–Stein shrinkage estimator decreases the influence of inconclusive parameters of standard data to acceptable values.

The possibility of using water-based lubricants in bearings is examined. An overview of the different types of water-based lubricants, their composition and properties, and methods of their application in bearings are provided. Particular attention is paid to studies showing the effectiveness of water-based lubricants in reducing friction and wear and increasing the energy efficiency of bearings. The research results confirm the potential of water-based lubricants for use in various industrial sectors where high performance and reduced environmental impact are required. Valuable information for engineers and manufacturers seeking to improve bearing performance and reduce the environmental impact is provided.

Electric spark machining allows coated parts to be coated with any electrically conductive materials, ensuring good adhesion to the base material, thereby restoring worn surfaces. However, limitations on the thickness of the applied coating significantly affect its distribution when restoring parts with wear of more than 0.2 mm. One way to solve this problem when restoring parts with increased wear is electric spark processing using composite electrodes with carbon nanotubes. Thanks to the use of a composite electrode with carbon nanotubes, it was possible to increase the thickness of the coating by 2–4 times, which will expand the range of the restored parts. At the same time, the microhardness of the coatings decreased when carbon nanotubes were added to the electrode, but under certain conditions it was possible to achieve a microhardness value comparable to coatings from BrO10S10 electrodes.

The supercritical deformation of quadrangular multilayer composite panels has been studied, taking into account geometric nonlinearity for deflections commensurate with the thickness of the plate. The solution of the problem on eigenvalues and eigenvectors is carried out in displacements by the Rayleigh–Ritz method. The dependences of the deflection amplitude on the contour forces were found, and basic relations were obtained for assessing the stress–strain state of composite quadrangular panels with arbitrary boundary conditions after loss of stability in compression and shear. Based on the strength criteria of anisotropic materials, the destructive forces after loss of stability are determined.

This study considers the application of standard operation array designs of cementing equipment using various numbers of pumping and mixing facilities for ensuring uninterrupted implementation of the cementing process. A design operational reliability model of various standard piping layouts is developed. Several piping layout types are considered individually. According to the outfit-mouth function chart, a ready-mix mud is pumped by the facility right into the well.