Abstract An efficient approach to determining dangerous relations between design parameters for a submerged pipeline transport system with the most frequently used tandem position of tubes (one after another downstream) intended to ensure accident-free operation of the structure under consideration is presented. To solve this problem, the effect of the particular position of pipelines on the character

Abstract This work presents the results of study of an alloy with the shape memory effect on corrosion resistance under various operating conditions as applied to pipeline connections with couplings made of titanium nickelide.

Abstract In this paper, methodological approaches to improving the accuracy of calculating the complex little-studied technological process of torsion forging based on computer simulation are provided. A method for setting the inverse problem for one of the known types of compression tests for aluminum alloy samples is presented. The results of simulation tests and their comparison with the data obtained

Abstract In this paper, the processes occurring during laser-shock-wave processing of titanium alloys with the shape memory effect by the methods of dimensional analysis and finite element modeling are discussed. The main dimensionless parameters that control the distribution of residual stresses and the depth of the plastic zone arising during laser-shock-wave treatment were established to be the

Abstract Topical aspects of assessing the effect of crankcase gases of an internal combustion engine on the operational properties of engine oil taking into account its service life are considered. For a mathematical description of the change in the condition of engine oil, a complex criterion for assessing oil operational properties and a criterion for assessing the saturation with crankcase gases

Abstract This study is aimed at a understanding of the thermal field peculiarities of various carbon threads. We perform experimental studies of various types of carbon threads under various levels of stresses applied to them. To investigate the thermal fields obtained, we engaged the theory of fractals to estimate the degree of thermal field ordering. We find that the carbon thread in a skin has better

Abstract— The spatial problem about the elastohydrodynamic lubricantion of a profiled roller accounting for the complicated geometry of the inlet boundary of the lubricant film is solved. This formulation simulates conditions of fully flooded or insufficient lubricantion, which may contain friction units such as gears and roller bearings. The set of integrodifferential equations with boundary conditions

Abstract The paper presents a method for assessing the probability of fracture of structural components of technical systems subjected to monotonic and cyclic loading, which permits taking into account the scatter of mechanical properties of materials and the size of macrodefects passed into operation by means of nondestructive testing. The presented method can be used in the implementation of probabilistic

Abstract In this article, we present a refined mathematical model of the stress–strain state of multilayer composite cylindrical shells taking into account the piezoelectric effect. The displacements and the electric potential of the shell are represented as polynomials in the normal coordinates two degrees higher in comparison with the classical Kirchhoff–Love type of theory. A mathematical model

Abstract An electrohydraulic servo actuator is used as an example to show how numerical data on the parameters of the components and assembly units supplied to the assembly section allow control of the assembly process, its qualitative transformation, and refinement of the characteristics of finished products. The described approach to the arrangement of the assembly process may be applied to any product

Abstract An analytical method for determining the compliance of gear teeth, the load distribution factors, and the bending stresses is proposed. To solve the problem about the stress–strain state of the gear tooth, the latter is represented as a wedge with the angle of the roll corresponding to the pressure angle of the involute tooth. The mathematical model of the loaded tooth is given in the form

Abstract— Root cause analysis is carried out to explain the break in a torsion shaft installed in an internal combustion engine (ICE) and inside the overdrive gearbox at the inlet of the transmission torque converter and inside the turning mechanism in a lightweight caterpillar vehicle having a high specific power (more than 30 hp/tf). It is proposed to install a spring-friction torsional vibration

Abstract Flutter of unmanned aircraft at hypersonic speeds is one of the understudied problems facing the designers of hypersonic vehicles. Modern methods for calculating aeroelastic stability either solve simplified versions of real problems (for example, without taking physicochemical phenomena into account) or require high computing power. This paper describes a methodology for calculating the supersonic

An Erratum to this paper has been published: https://doi.org/10.3103/S1052618821030134

Abstract In this paper, we consider the constructive effect of the nozzle armament of metallizers (nozzle-tube, nozzle-diaphragm) on the geometry and physical features of a transport gas flow at a system pressure of 0.4 and 0.5 MPa, which affects the mechanics of movement and dispersion of the sprayed material. We present the initial stage of estimating the effect of technological parameters of the

Abstract The change in the abrasive resistance under testing composites based on an epoxy matrix filled with sludge originating from cutting tool sharpening exhibits the same character for all compositions, which reflects the process of wear self-organization. A composite filled with abrasive particles originating from grinding wheels has the maximum abrasive wear resistance.

Abstract The distribution densities of the laws of distribution of random operating times known in the theory of reliability, for example, exponential, Weibull–Gnedenko, Erlang, normal, Maxwell, and many others are not more than unimodal and not more than two-parameter. This paper discusses formulation of problems of determining the share of each distribution function in a mixture (distribution functions

Abstract In this paper, a method for trackless adjustment and testing of special purpose laser rangefinders and the scheme and design of the installation process developed for these purposes are presented. A new principle of the distance setting and its algorithmic correction using special software to improve the accuracy is implemented in the installation. The technical characteristics of the installation

Abstract During operation, parts of the high temperature section of land-based gas turbine units are subjected to an aggressive gas environment, which affects adversely the durability of components and assemblies. When analyzing operational fractures of the ZhS32-VI alloy blade roots after operation as parts of land-based gas turbines, we found that cracks developed in the places of active sulfide-oxide

Abstract The correlation dependences between the safety factors of the yield stress and the safety factors of the crack resistance characteristics (fracture viscosity, crack resistance diagram, critical J integral, and crack-tip opening displacement) are provided. It is proposed to calculate the probabilistic safety factors at preset failure probabilities by means of the probabilistic safety factors

Abstract This article examines, using the theory of similarity and dimensionality, the surface of a part of bodies of revolution before plasma spraying of wear-resistant coatings, which plays an important role in activating the processes of bonding between the sprayed particles and the surface of the part. Physical processes of the interaction of the surface of the part before plasma spraying of wear-resistant

Abstract To predict the wear resistance of polymer composite materials with a spatial structure of the filler, a criterion for the tribotechnical filling efficiency is proposed. The mathematical expression that determines the value of this criterion contains the ratio of the friction coefficients of the pure polymer and its composite. Experimental studies of the wear resistance of the F4K20 composite

Abstract The assessment of the vibration strength of elastic metal structures for various purposes is carried out on the basis of mathematical modeling. Proper determining the internal friction coefficient of the metal is of key importance, because this value significantly affects the values of the natural frequencies of damped oscillations and is reflected in the conditions of resonances of various

Abstract Nanostructured boehmite additives in lubricating oils for a D-243 diesel engine and drilling rig gearbox during the breaking-in period are studied. It is demonstrated that the addition of boehmite powder and a surface acting agent to the M-10G2k engine oil accelerates and improves the quality of running of the diesel engine by up to two times, contributing to rapid achievement of the rated

Abstract The kinetics of changes in the lubricating, antifriction, and antiwear properties of Aero Shell Grease 33 and Era VNIINP-286M lithium lubricants is considered under the conditions of stopping the supply of lubricant to the frictional contact zone. A relationship between the level of self-organization disturbance in dissipative structures and the specific work against friction is established

Abstract In this paper, we present a solution of the inverse kinematic problem for a one-degree-of-freedom hexapod with a circular guide. The problem was solved applying analytical and numerical calculation methods using MATLAB package. The given algorithm for solving the inverse problem also allows studying the six-degree-of-freedom hexapod. The paper presents assembling computational models (virtual

Abstract The effect of the main thermal sputtering parameters on the cohesive strength of the coating with respect to the substrate surface is considered. At the stages of particle heating, acceleration, transfer, and contact, the relationships between the parameters of the sputtering process and the factors that determine the cohesive strength between the sputtered material and the substrate surface

Abstract The initiation and growth of fatigue cracks in the runner blades of hydraulic units is one of the major causes that limit their service life. Practice shows that the current diagnostic systems for hydraulic units do not permit timely identification of cracks in the operating equipment. The data from the numerical experiment demonstrate that high stiffness and the existence of particular eigenmodes

Abstract This article describes design features of welded or brazed joints of pieces made of materials with shape memory. The influence of welding and brazing on the properties of a shape memory alloy and shape memory work has been demonstrated.

Abstract An approach to the study of wave processes in the human cardiovascular system is presented in order to identify the constituent components in the complex signal of the pulse pressure wave—direct and reflected waves. This makes it possible to calculate the pulse wave propagation time and velocity, which are indicators that play an established role in the diagnosis and prognosis of cardiovascular

Abstract A promising method for obtaining a SiC-based ceramic construction material for products of complex geometry has been developed. It is suggested to carry out mechanical processing of prepared ceramic blanks, made using a temporary organic binder, before high-temperature sintering. This approach can be used in mechanical engineering and marine, aviation, and special equipment design.

Abstract This article proposes a wave technology for producing film composite materials based on native starch with Na-montmorillonite, which are intended for the prolonged release of biologically active compounds. It is shown that the use of wave effects at the stage of preparing a suspension for film composite materials promotes the formation of composites characterized by improved parameters of

Abstract The article presents a new design of a free power turbine for mobile industrial vehicles. It is a three-stage radial turbine placed directly on the generator shaft. This design represents a single unit of generator and free power turbine, which significantly increases the reliability of the unit, because it excludes additional mechanical units of torque transfer from the turbine to the generator

Abstract The problem of residual stresses that arise during the curing of products of polymer composite materials and cause warping (warpage) is considered. A calculation model is proposed that allows for the prediction of residual strains and design of predictive molding tools. The approach developed ensures a high accuracy of manufacturing articles of polymer composite materials. The influence of

Abstract In this article, by means of mathematical modeling, propagation of the response to a heat signal in the “human body–a gap–woven electric heater–heat-insulating layer–environment” heating system is analyzed. On the base of this study, we discover that the woven electric heater can act not only as a heater, but also as a receiver of external thermal signals caused by the impact of the heater

Abstract The modes of small oscillations are studied in a rod having an axis in the shape of a three-turn cylindrical helix using the expansion into oscillating eigenmodes and the method of vortex elements. Oscillationós are excited by pressure pulsations generated as a result of the processes of intense vortex formation when a spatial incompressible flow flows around the rod. The polyharmonic nature

Abstract Mixed parametric oscillations and self-excited oscillations in a system with a nonideal power source with delays in the elastic and frictional forces are considered. The direct linearization method is used for solving nonlinear equations. The stability conditions of stationary oscillations are determined. Calculations were carried out, and it appears that the delay leads to some interesting

Abstract The falseness of the idea about the independence of contact deformation of circular cylinders on their radius is shown. It is demonstrated that the total deformation of the roller and the plate is independent of the radius as observed in experiments with the roller compressed between two plates made of the same materials. It is stated that the known formula calculating the contact deformation

Abstract We study the damping efficiency of torsional vibrations of a body using a dynamic vibration damper containing a system of successive impactor pairs with magnets as colliding elements. Dimensionless essentially nonlinear differential equations of motion of the protected body and magnetic elements are obtained. The influence of the designed parameter selection of the vibration damper on the

Abstract In this paper, the literature data on the results of theoretical and experimental studies aimed at the development of the scientific foundations of evaluation of residual stresses in ferromagnetic materials according to the measurements of their magnetic parameters are analyzed. The data that indicate the reasonability of multiparameter control for the extension of the range of controlled

Abstract In this paper, we describe the concept of setting the base of large-sized parts with a diameter of up to 8300 mm and a mass of up to 120 tons, such as a bandage of a rotating cement kiln during machining using a mobile robotic machine. The issue of controlled cutting to ensure accurate shaping of a large-sized part with a thickness of the removed metal layer up to 6 mm is considered. Processing

Abstract The pattern of the interaction between powder particles and metal vapors is developed. To ensure a guaranteed supply of PAs to the heated region with the use of laser irradiation, a model for theoretically analyzing the motion paths of PA particles carried to the zone of construction with a gas jet in 3D Metal Printing is proposed.

Abstract In this article, on the basis of a refined theory, we study the stress state of a conical shell of the “boundary layer” type. In comparison with the classical theory, the sought displacements of the shell are approximated by polynomials along the coordinate normal to the median surface with a degree two units higher. Based on the equations of the three-dimensional elasticity theory and the

Abstract The antifriction properties have been determined experimentally for a carbon–carbon composite in the course of sliding friction against 40Kh13 steel in an environment of carbon dioxide. Changes in the friction coefficient upon heating to 800°C have been investigated in the velocity ranges from 0.05 to 0.25 m/s at a contact pressure ranging within 0.5–1 MPa. The novelty of the investigation

Abstract This work presents the results of studying of characteristics of wear resistance of gas-dynamic coatings obtained using electroerosive carbides, prepared by the method of electroerosive dispersing from wastes of VK8 hard alloys in distilled water and illuminating kerosene. Worn plates of the cutting tool from sintered hard alloys of the brand VK8 were used as dispersed material as well as

Abstract In this paper, we establish the scientific basis for the generation of intense hydroacoustic waves in a liquid as a result of the detonation of a stoichiometric mixture of hydrogen and oxygen. The idea of the possibility of carrying out this process with the help of a deep-water electrolyzer, which was confirmed experimentally, is expressed. The processes of combustion and detonation of a

Abstract This paper describes the results of the development of functional material represented by a dispersion-strengthened composition material based on aluminum and prepared by internal oxidation. Various types of tribological tests were employed; more specifically, friction tests of the specimens to determine the friction coefficient of the DSCM-brake shoe and tests of the specimens to determine

Abstract In this article, a model of the interaction between the jaw of a vibratory jaw crusher with the rock under processing in the form of a lump material is considered. To describe the motion of the rock and its sequential fracture into finer fragments, the crushing chamber is divided into zones of equal height. In each current zone, the material to be processed breaks into smaller fractions after

Abstract The potentialities concerning the combination of a cold-air minimum quantity lubrication technique (CAMQL) with a system for grinding-wheel cleaning by an air jet (WCJ) while grinding a heat-resistant nickel alloy are studied. The results of experimental studies show that, using the CAMQL + WCJ technique, the cutting force components are significantly reduced, the temperature of the contact

Abstract— The results of analysis of the dynamic properties of a vibrating technological machine with an electrodynamic actuator of oscillations during its operation under a nonlinear technological load are presented. The amplitude–frequency performances of the machine have been obtained, in both the idle and operating modes when the actuator is powered by current and voltage sources. The conditions

Abstract In the operation of modern gas and steam turbines, the amount of deposits on the aggregate surfaces inevitably increases (mainly in the form of amorphous silicon), which leads to metal corrosion and erosion damage. The relevance of solving the problem of removing technological pollution in the process of repairing gas and steam turbines in order to restore the design capacity of the equipment

Abstract This study presents a new variation of slider-crank mechanism designed by coupling a planar and a screw groups of zero mobility. In this mechanism the rotation of the driving link converts to the motion of the end-effector along a screw path. A detailed assembling computational model of the synthesized mechanism is presented, according to which kinematic and kinetostatic (force) analyses are

Abstract The results of study of the working process, the local heat transfer in the combustion chamber, and the thermal state of the piston of a hydrogen engine with an external mixture formation are analyzed. Studies of the local heat transfer coefficients were carried out using a 3D-CRFD-mathematical model developed and verified on the basis of the experimental results, first used to study a hydrogen

Abstract In this article, the concept of dynamically fractal structures (dynamic fractals) is introduced. The concept supposes that the dynamic, i.e., elastic–inertial, parameters of the constituent cells change on an equal scale. It is shown that a lengthwise descending dynamic fractal has the property of amplifying the input signal along the structure. On the contrary, a lengthwise increasing dynamic

Abstract A mathematical model of nonstationary rotation modes of the rotor of a centrifugal pump is built with allowance for the displacement of the rotor mass center relative to the rotation axis that causes vibrations in cooling systems of spacecraft. The process of acceleration and ascent of the rotor with subsequently reaching the mode of quasi-stationary oscillations is considered.

Abstract— This study is devoted to the features of friction of fluoroplastic-containing composite coatings under low-velocity loading.

Abstract In this paper, we substantiate of the possibility of reducing the weight and size characteristics of electric drives operating under high loads. To solve the problem, a geared motor design was developed. Unlike the existing analogues, the proposed design solutions are based on the use of wave transmission with intermediate rolling bodies, which allows obtaining high values of the gear ratio

Abstract The influence of a corrosive medium on the characteristics of endurance strength of samples of chrome–nickel steel 38KhNMA was considered. It was shown that, under the conditions of the impact of a corrosive medium, the issue that the endurance strength must be estimated by the results of statistical tests of laboratory samples while bringing the results of their processing in determination

Abstract This paper presents a mechanism with parallel structure that is classified to the class of l‑coordinate mechanisms. The section of the singularity zone (of the zone of singular positions) is determined for this mechanism. The section is constructed at a constant orientation of the output linkage.

Abstract The aim of this research is theoretical analysis and mathematical modeling of AC measuring transducers based on magnetodielectric cores for automation systems of oil refineries. An analytical study of the magnetization curve is carried out, an equivalent circuit is constructed, and a mathematical transducer model on its basis is obtained. A numerical study of the proposed transducer is carried