AbstractA posteriori estimates of the parameter of reliability obtained on the basis of the mathematical expectation of the parameter and the variance calculated by the results of a limited number of Bernoulli trials taking into account additional information are examined. The novelty of the results consists in the predictions of the accuracy of the estimation of the parameter of reliability depending on the method of a priori information accounting in addition to a limited number of failure-free tests. The scope of the obtained results includes estimates of the indices of reliability of a highly reliable nonrepairable single-action item based on a small number of tests using a priori information.

AbstractA method for comprehensive assessment of the effectiveness of a cutting tool during its introduction into operation is presented. The method allows not using the monetary equivalent when normalizing the parameters; therefore, all the initial parameters are applied in their natural units of measurement. The obtained partial effects show the advantage of a prototype product in comparison with the base one in terms of a separate property. The combined effect gives the idea of the entire complex of the properties of the product under consideration.

AbstractIn this work, new devices and tools for minimally invasive endoscopic surgery are considered, which were developed by Mechanical Engineering Research Institute of the Russian Academy of Sciences, together with the Central Clinical Hospital, Russian Academy of Sciences. Experimental samples of the devices and tools are presented.

AbstractThe dynamics of a rotor with a massive disk is considered for the case of interaction with oscillation limiters represented by viscoelastic supports discretely arranged in the disk rotation plane. Differential equations that describe the transverse radial and angular rotor oscillations in the course of rotation are obtained. The solution is presented in the form of a second-kind integral of the Fredholm equation. The supercritical rotor behavior after the Poincaré–Andronov–Hopf bifurcation caused by internal friction in the shaft material is studied. A generalized definition of the rotor precession index has been introduced, making it possible to calculate the frequency and direction of precession based on the information concerning transverse rotor oscillation.

AbstractThis work is devoted to evaluation of the efficiency of a new technology for repairing gear pumps with the restoration of worn surfaces of resource-defining mates of parts and increasing their wear resistance. Hydraulic pumps repaired by the proposed technology showed an increase in the average overhaul life in conditions of real operation of 1.07 times as compared with the resource in the prerepair operation period.

Abstract—A possible way to improve the operation efficiency of complicated systems is the method of coherent operation of individual system elements. The operation efficiency of a machine tool can be improved by provision of its optimum position between the electric motor drive and a rigidly coupled cutting tool. The optimum mutual position of the electric motor shaft and the cutting tool can be achieved by coincidence of the maximums of the generated and consumed torque. Any deviation of the mutual position of the maximums of generated and consumed torque leads to alternating oscillations of torque in the system of rotating bodies: electric motor shaft–cutting tool. A drawback of the generated torque against required torque leads to an increase in sliding of the electric motor and a local decrease in efficiency for about 180 degrees of rotation of the electric motor shaft.

AbstractFor the first time, it has been shown that the enzymatic hydrolysis of corn and potato starch affected by β-amylase can be intensified using wave resonant effects. It has been established that the concentration of sugary substances formed resulting from the fermentation of corn starch, after two hours of resonant wave treatment is 3.5 times higher than it is in the case of the traditional stirring mode. In addition, the wave treatment technique provides an increase in the yield of sugars in the course of the enzymatic processing of potato starch. The obtained results represent a basis for the development of highly efficient resource-saving wave technologies for the production of sugary substances and porous starches by means of enzymatic hydrolysis.

AbstractThe regularities of development of fatigue cracks under harmonic and operational loading processes in samples of low-alloy cast steel of a freight car bolster are compared.

AbstractThe method of molecular-dynamic modeling was applied for creating models of polyether ketone and two of its nanocomposites with fillers in the form of copper nanoparticles and with fullerene. The results of comparative study of the deformation-strength properties of these materials by means of uniaxial tension at a constant strain rate are presented. It was obtained that, when filling polyether ketone with fullerene, the elasticity value of the composite decreases by approximately two times, and in the case of filling of the same matrix with copper nanoparticles, its value increases by approximately 30%. At the same time, the average energy of intermolecular bonds of the composite with copper nanoparticles is 2.65 times greater than that of the composite with fullerene.

AbstractBased on the results of experimental observations, mathematical models of the impact of the factors under study on repression-wave colmatation are obtained. The values of the factors are established at which mud solutions acquire a higher resistance to sedimentation of the solid phase due to its concurrent dispersion increasing the efficiency of colmatation of absorbing hole sections.

AbstractExperimental studies of the tribotechnical characteristics of motor oils with additives based on serpentinite are presented. The tests carried out made it possible to determine the effect of nanomodifiers on the wear intensity and temperature of the lubricating layer under mixed friction conditions.

AbstractOn the example of planar mechanisms with rotational pairs, a comparison is made of two types of graphs that describe their structure. Graphs G of the first type, corresponding to hinged-lever mechanisms, consist of vertices corresponding to the hinges of the mechanism, and of edges corresponding to its levers. The vertices of graphs \(\mathcal{G}\) of the second type correspond to links of the mechanism, and the edges correspond to kinematic pairs. It turns out that in the absence of combined hinges, the graphs G and \(\mathcal{G}\) are equivalent for describing the structure of mechanisms. In the presence of combined hinges, the graph graph \(\mathcal{G}\) and the graph \(\mathcal{G}{\kern 1pt} '\) obtained by its modification in the theory of mechanisms, in contrast to the graph G, do not provide complete information about the structure of the mechanism.

AbstractStructural metallographic studies of the VZh178P Ni-based superalloy after rotation friction welding performed using the PSTI-400 unique Russian-made setup are presented. The effect of individual welding parameters and their combinations are studied on the microstructure of welded joints of the heat-affected zone and the main material and Vickers microhardness in these areas. After preparing, welding, and cutting, the samples were heat-treated and the results were presented.

AbstractThe features of the acoustic impact on aircraft aggregates made of polymer composite materials are investigated. A technique for setting the wave angle is described; it equalizes the scale factors of both measuring channels of the differential aggregate made of polymer composite materials and compensates for the cross-damping error. Analytical expressions are obtained for the scale factor and the zero offset of the differential aggregate made of polymer composite materials. This scale factor, in contrast to the discrete noise oscillation mode, does not depend on the resonant oscillation amplitude and frequency. The operating mode of the aggregate made of polymer composite materials is shown to have an ability to compensate for the resonator frequency difference, when measuring the angular velocity, by means of the control system.

AbstractThis article discusses the possibility to produce hybrid workpieces from aluminum alloys AMg2, AMg5, and AMg6 using combined upsetting deformation with a surface shear (torsional upsetting). The finite element simulation of shape formation using the QForm 10.1.5 software has been applied. The obtained rheological models of deformed materials and the specially developed friction.sliding_velocity subroutine have allowed us to obtain simulation results agreeing well with the experimental data. Metallographic studies have confirmed the high joining quality of workpieces in the contact area.

AbstractAccording to the estimation of experts, the number of breakdowns and accidents, as well as wear of parts of standard equipment, is 3–5 times (in some cases 8–10 times) greater during operation at low temperatures than under temperate climate conditions. Therefore, enhancing the quality of surfaces of various machines and mechanisms operating in the Arctic is relevant. This article suggests a method of combined processing that allows one to increase hardness, reduce roughness, obtain optimal residual stresses, and create regular surface microrelief to keep the lubricant on the surface. However, these properties must be maintained at temperatures down to –50°C. The effect of low temperatures on the surface layer of details after combined processing is studied. This work is useful for experts engaged in the design of machines for operation in the Arctic.

AbstractThis article discusses the so-called gear train with adapted properties. Such gear trains are used to increase the load capacity of gear coupling by decreasing the maximum contact stresses by means of an increase in teeth contact compliance operating under skewed conditions. An approach has been proposed, including an analytical solution to the problem on its basis, and the equations for determination of the maximum contact stresses of gear teeth with annular grooves have been obtained. The decrease in the contact stresses of teeth with adapted properties upon skewing has been estimated and compared with those of regular teeth.

AbstractMathematical experiments on the study of dynamic thermal processes that occur during the heating of technical devices in the cold are considered. The novelty is in obtaining volume representations of thermal processes occurring in these devices over time: their heating at a lower temperature range limit, using previously accumulated thermal energy in a warm room and increasing it due to additional heating by woven electric heaters when the devices are in a warm room. This article may be of interest to developers of heating systems that use autonomous sources of electricity.

Abstract—A comprehensive study of the EP648 Ni-based superalloy obtained by selective laser melting followed by high-temperature annealing has been carried out. The macro- and microhardness have been studied, and the microstructure has been analyzed, while tests for brittle fracture resistance were carried out. The quantitative and qualitative analyses indicate possible structural deviations affecting the properties of products.

AbstractApproaches to the development, evaluation of efficiency and expediency of control, problem statements, and their mathematical models to make it possible to solve the problem of synthesis of adaptive programs of safety control of the technical state of a complex technical system are presented.